BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Department of Aerospace Engineering - ECPv6.6.3//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-ORIGINAL-URL:https://aero.iisc.ac.in
X-WR-CALDESC:Events for Department of Aerospace Engineering
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:Asia/Kolkata
BEGIN:STANDARD
TZOFFSETFROM:+0530
TZOFFSETTO:+0530
TZNAME:IST
DTSTART:20250101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250203T153000
DTEND;TZID=Asia/Kolkata:20250203T170000
DTSTAMP:20260418T112656
CREATED:20250130T070018Z
LAST-MODIFIED:20250130T070404Z
UID:10000051-1738596600-1738602000@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Ultrasonic Guided Wave-based Inspection of Additively Manufactured Components
DESCRIPTION:Layered structural components\, such as laminated composites and those made via Additive Manufacturing (AM)\, are widely used in aerospace and automotive industries due to their various advantages. The layer-wise approach allows for intricate and multifunctional designs\, but their performance depends on factors such as joining technique\, material properties\, manufacturing conditions\, and service environments. These layered components are susceptible to defects like delamination\, debonding\, porosity\, residual stress\, cracks\, and surface roughness\, affecting mechanical performance. In AM\, process parameters like laser power\, scan speed\, layer thickness\, hatch spacing\, scan strategies\, solidification strategies\, and build chamber conditions impact the quality of the produced parts. Optimizing these parameters and using in-process monitoring systems can minimize these defects. This thesis focuses on developing an ultrasonics-based monitoring system for AM processes.\nThis work involves the modeling and analysis of wave propagation in multi-layered structures. For this purpose\, three different approaches based on the modeling of interlayer interface bonding have been formulated. The developed models allow for the analysis of different levels of interface bonding\, including perfect bonding and complete debonding. The AM components are idealized as one-dimensional higher-order planar frame structures. The equations of motion are derived from Hamilton’s principle\, and the Fourier transform-based Spectral Finite Element Method (FSFEM) is used to perform the spectral analysis and the spectral elements formulation. The FSFEM formulation results in the dispersion curves and responses in frequency domain\, which is transformed into the time domain by performing the inverse Fast Fourier Transform. A concept of effective thickness is introduced to match the cut-off frequencies in the dispersion curves obtained from the developed approaches with those of exact Lamb waves\, which are used in determining the shear correction factors necessary for higher-order frame formulations.\nThe developed models undergo two levels of validation involving the validation of the dispersion curves\, and time-domain responses. Reference dispersion curves are computed from open-source software for dispersion curve computation\, while the reference time-domain responses are obtained from experiments and the Finite Element simulations.\nFurther\, this thesis focuses on examining the interaction of ultrasonic-guided waves (UGW) with two types of defects – porosity and delamination/debonding. The impact of porosity is analyzed through porosity-dependent constitutive models. Various levels of delamination/debonding are numerically simulated by varying the interface bonding strength in the defect region. Additionally\, the Semi-analytical Finite Element Method is employed to perform spectral analysis of defective structural waveguides with complex geometry\, where the impact of various defect parameters\, such as size\, depth\, and orientation\, have been investigated. Further\, the developed FSFEM models are employed to solve inverse problems for material property characterization\, porosity estimation\, and interface bonding strength characterization. Ultimately\, these models provide a framework for analyzing the dynamic behavior of multi-layered structures\, offering insights into the interaction of UGW with defects. \nAll are welcome. \n  \nSpeaker :   Anoop Kumar Dube \n  \nResearch Supervisor : Prof. S. Gopalakrishnan FNAE FASc\, FIMechE\, CEng
URL:https://aero.iisc.ac.in/event/ph-d-engg-ultrasonic-guided-wave-based-inspection-of-additively-manufactured-components/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/01/Anoop-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250210T140000
DTEND;TZID=Asia/Kolkata:20250210T170000
DTSTAMP:20260418T112656
CREATED:20250206T052542Z
LAST-MODIFIED:20250206T052542Z
UID:10000052-1739196000-1739206800@aero.iisc.ac.in
SUMMARY:MTech (Res): Woven composite modeling
DESCRIPTION:In this work\, a novel sub-mesoscale model of woven fabrics is developed using nonlinear finite element methods. The main aim of the work is to develop a framework for modeling woven fabrics. The yarns are modeled as beam elements that move freely in space and undergo large deformations and rotations. A geometrically-exact beam theory (GEBT) used to model composite beams of arbitrary cross sections is considered to model the yarns. The variational asymptotic method (VAM)\, in tandem with the beam model\, offers the advantage of modeling beams of arbitrary cross sections. A surface-to-surface contact model is developed\, considering that the contact occurs at a point on the surface. The robustness of the contact model is tested by designing a patch test. The overall mesoscale model of woven fabric is validated using experimental results of biaxial tests performed on a plain glass weave woven fabric. The biaxial simulation is performed by varying the number of yarns in the mesoscale model to study the behavior of the model and demonstrate a representative volume element (RVE).\nThe yarns are made up of fibers twisted together. An isotropic model is an approximation that works well on the mesoscale\, but a more general model is needed to include fiber-level information. The yarns can be made of 10\,000 to 60\,000 fibers twisted together. Modeling individual fibers and the interaction between them can be computationally expensive. The variational asymptotic method-based homogenization (VAH) is used to get the homogenized properties of yarn. A representative volume element of woven fabric\, with yarns made of coated fibers\, is simulated by using homogenized properties obtained through VAH.\nThe framework can be extended by introducing friction between yarns in the contact. Further\, the uncertainty in the input parameters can be quantified by propagating the uncertainty through the system using uncertainty quantification (UQ) techniques.\n\n\nSpeaker: R Adhithya\n\nResearch Supervisor:  Dineshkumar Harursampath
URL:https://aero.iisc.ac.in/event/mtech-res-woven-composite-modeling/
LOCATION:STC Conference Hall\, Ground Floor\, Department of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/02/Adhithya.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250218T160000
DTEND;TZID=Asia/Kolkata:20250218T170000
DTSTAMP:20260418T112656
CREATED:20250212T065012Z
LAST-MODIFIED:20250212T065012Z
UID:10000053-1739894400-1739898000@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Passive control and intermittent dynamics of the precessing vortex core oscillation in swirl flows
DESCRIPTION:Swirl is used in modern gas turbine combustor nozzles to achieve   reliable flame stabilization and efficient fuel-air mixing. The swirl   component in the nozzle jet flow induces an axial vortex. At high swirl   intensities\, vortex breakdown occurs\, creating a recirculation zone in   the flow known as the vortex breakdown bubble (VBB). VBB appearance is   typically accompanied by the emergence of a global self-excited   instability where the VBB precesses around the flow axis and causes the   axial vortex to form a co-precessing helical structure. This  instability  is referred to as the precessing vortex core (PVC). Several  prior  studies have shown that the PVC oscillation can significantly  impact  emissions and thermoacoustic stability characteristics of the  combustor.  This thesis studies the characteristics and passive control  of the PVC.  The non-reacting flow field in an axial entry swirl nozzle  combustor at  the Massachusetts Institute of Technology (MIT)\, USA\, is  investigated.  Planar three component time resolved velocity field  measurements in the  combustor for combinations of two swirl numbers\, S  = 0.67 and 1.17 and  centrebody diameters of Dc = 9.5 mm\, 4.73 mm and 0  mm (i.e. no centrebody) are analysed. All cases are at a fixed bulk  Reynolds number of 20\,000. A new modal decomposition method based on  wavelet  filtering and proper orthogonal decomposition (WPOD) is  developed in  this thesis to analyze the global non-stationary dynamics  of these  flows. WPOD analysis for configurations without a centrebody  for both  swirl conditions revealed a coherent PVC oscillation in the  flow. Large  eddy simulation (LES) is performed for configurations  without the  centrebody and with the Dc = 9.5 mm centrebody for both  swirl numbers.  For all four cases\, LES accurately captures flow  statistics and PVC  characteristics observed in the corresponding  experimental measurements.  Linear stability analysis (LSA) on the time  averaged flow for each value  of S in the configuration without a  centrebody yields a nearly neutrally  stable global mode whose  oscillation frequency and spatial flow  oscillation amplitude  distribution characteristics match those induced  by the PVC in each  case. The wavemaker region associated with the PVC  mode is shown to be  situated at the upstream end of the VBB on the flow  centreline.  Therefore\, the introduction of a centrebody disrupts the  wavemaker and  suppresses the PVC as the experiments verify. In both LES  and  experimental studies for the cases with the Dc = 9.5 mm centrebody\,  low  amplitude PVC like oscillations\, which are also intermittent in the   S=0.67 case\, are observed. Resolvent analysis (RA) for helical forcing   on the time averaged flow field from LES for these cases is performed.  RA reveals a low rank\, optimal helical mode pair at frequencies where   PVC like oscillations are observed. The output mode amplitude   distribution characteristics match those of the PVC like oscillations  at  both values of S. For the S=0.67 case\, the input mode structure  suggests  that intermittent separation between the centrebody wake and  the VBB\,  due to turbulence results in the startup of PVC oscillations\,  which  subsequent merger then suppresses. For the S=1.17 case\, the input  mode  structure shows that stochastic forcing of the flow by turbulence\,  generated by vortex shedding off the upstream swirler\, results in sustained PVC like oscillations due to a low-rank strongly amplified   flow response at the PVC frequency revealed by resolvent analysis. \n  \nSpeaker: Saarthak Gupta \nResearch supervisor: Prof. Santosh Hemchandra
URL:https://aero.iisc.ac.in/event/ph-d-engg-passive-control-and-intermittent-dynamics-of-the-precessing-vortex-core-oscillation-in-swirl-flows/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/02/Saarthak-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250224T160000
DTEND;TZID=Asia/Kolkata:20250224T170000
DTSTAMP:20260418T112656
CREATED:20250221T055800Z
LAST-MODIFIED:20250221T055800Z
UID:10000054-1740412800-1740416400@aero.iisc.ac.in
SUMMARY:MTech(Res): Adjoint-Based Aerodynamic Shape and Mesh Optimization with High-order Discontinuous Galerkin Methods
DESCRIPTION:The aerodynamic shape of an aircraft plays a critical role in its performance. Aerodynamic Shape Optimization (ASO) modifies the shape to achieve desired performance metrics\, such as reduced drag or increased lift. ASO integrates numerical optimization techniques with Computational Fluid Dynamics (CFD). Gradient-based optimization techniques are widely employed for ASO. The adjoint solution enables the accurate and efficient computation of the gradients of the performance metrics with respect to the shape parameters. Performance metrics are derived from CFD solutions\, which inherently contain inaccuracies. These inaccuracies can affect the reliability of the optimization process. High-order methods\, like Discontinuous Galerkin (DG)\, offer improved accuracy for a computational cost comparable to Finite Volume methods in compressible flows\, making them well-suited for ASO. Adaptive mesh refinement can further improve the accuracy of simulations. The adjoint solution used for computing gradients also finds application in mesh adaptation. Combining adjoint-based mesh adaptation with gradient-based ASO provides better control over the inaccuracies during optimization. \nTowards this\, the present work performs ASO using high-order DG methods and devises strategies for incorporating adaptive mesh refinement. The shape is defined using smooth splines\, and the Free Form Deformation (FFD) method controls shape changes. With changes in the geometry\, the mesh needs to move to be consistent with the modified shape. A mesh deformation strategy ensures that the mesh evolves smoothly with geometry. A gradient-based method employing the Sequential Quadratic Programming (SQP) algorithm is used for optimization. The adjoint solution computes the gradients and passes them to the optimization algorithm. Optimization for a set of drag minimization problems\, including benchmark Aerodynamic Design Optimization Discussion Group (ADODG) test case 1 and inverse design problems\, is performed on non-adapted meshes. \nFurthermore\, a strategy is formulated to incorporate adjoint-based mesh adaptation within the optimization process. Based on the value of adjoint-based error estimates\, the strategy decides on instances of the optimization process that require control of the errors and\, thus\, mesh adaptation. Such a strategy leads to automated control of errors in the performance metrics\, thus improving the reliability and efficiency of the optimization process. \n  \nSpeaker : Pandya Kush Tusharbhai \nResearch Supervisor : Aravind Balan
URL:https://aero.iisc.ac.in/event/mtechres-adjoint-based-aerodynamic-shape-and-mesh-optimization-with-high-order-discontinuous-galerkin-methods-2/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/02/Slide3.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250305T140000
DTEND;TZID=Asia/Kolkata:20250305T170000
DTSTAMP:20260418T112656
CREATED:20250305T053106Z
LAST-MODIFIED:20250305T053338Z
UID:10000058-1741183200-1741194000@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Numerical Studies on the effect of core metal type and thickness on the mechanical behaviour of fiber metal laminates
DESCRIPTION:Fiber Metal Laminates are materials that combine metal properties with Fiber Reinforced Plastics (FRP) to improve mechanical performance. This research investigates the impact of core metal type and thickness on the tensile and impact behavior of FMLs. Initially two types of FML were modeled: GFML based on GFRP and HFML based on CFRP and GFRP. Numerical simulations were performed to predict FMLs’ behavior under low-velocity impact loading. Results showed that hybridization of CFRP with GFRP increased maximum force but reduced maximum displacement and energy absorption. Studies have shown that GFRP and CFRP layer positioning and thickness along the laminate the can enhance contact force and energy absorption\, but enhances the delamination at material interfaces. The importance of optimal stacking sequences is evident as hybridization also causes enhanced delamination. The study also\, examined the effect of the core metal layer thickness on low-velocity impact behavior of FMLs. It found that adding a thicker aluminum layer to the middle of the laminate improves energy absorption and reduces permanent displacement due to higher plastic dissipation. Laminates with thicker aluminum cores also show superior impact resistance\, making them suitable for impact-prone applications. Initial studies found that the metal layer in the fiber metal laminates plays a dominant role in achieving the desired properties. Hence\, the present study focuses on the role of core metal type and its thickness on the tensile\, low velocity\, and high velocity impact behavior of fiber metal laminates. Aluminum 2024 T3 – GFRP-based FML with a titanium 6Al 4V core layer and Titanium 6Al 4V – GFRP-based FML with an aluminum 2024 T3 core layer are considered to study the effect of the core metal layer and its thickness on the tensile and impact behavior of fiber metal laminates. Tensile simulations were performed for different core metal layers with varying thicknesses ranging from 0.8 mm to 2 mm at the core position of the laminate. The results show that aluminum-based FML with a titanium core improves elastic modulus\, yield strength\, ultimate tensile strength\, and failure strain compared to titanium-based FML with an aluminum core. In addition\, the deep neural network has been used to predict the stress-strain curve of FMLs\, focusing mainly on the thickness of the core metal. The DNN results closely match the FEA results. In continuation\, numerical simulations were carried out to study the effect of the type of core metal and its thickness on the low-velocity impact behavior of fiber metal laminates. The results showed that an increase in the thickness of the titanium core in aluminum-based FMLs reduces the energy absorption capacity and the plastic dissipation energy while increasing the maximum force and displacement ratio. The study shows that titanium as the core layer is recommended when the thickness of the titanium layer is less than the total thickness of the aluminum layer. In addition\, numerical simulations were also carried out to evaluate the influence of the core metal type and its thickness on the high-velocity impact behavior of FMLs. The results indicated that the ballistic velocity increases with increasing thickness of the titanium layer. Laminates with thicker titanium layers showed higher impact resistance and energy absorption. This thesis establishes an approach to tailoring FMLs by describing the relationship of fiber hybridization\, core metal type\, and its thickness to achieve desired FML properties. The findings demonstrate the development of innovative hybrid materials with superior impact resistance\, tensile strength\, and energy absorption\, confirming their suitability for demanding engineering applications. \n  \nSpeaker: Sadananda Megeri   \n  \nResearch Supervisor: Narayana Naik G
URL:https://aero.iisc.ac.in/event/ph-dengg-numerical-studies-on-the-effect-of-core-metal-type-and-thickness-on-the-mechanical-behaviour-of-fiber-metal-laminates/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/SADANANDA.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250305T153000
DTEND;TZID=Asia/Kolkata:20250305T170000
DTSTAMP:20260418T112656
CREATED:20250303T052352Z
LAST-MODIFIED:20250303T052352Z
UID:10000056-1741188600-1741194000@aero.iisc.ac.in
SUMMARY:Multi-fuel combustion for sustainable aviation
DESCRIPTION:With the climate change becoming as one of the main challenges for human existence\, every sector has to contribute in reducing its climate footprint. Being an international and hard to abate sectors\, aviation is struggling to find a viable replacement for kerosene. This talk focuses on a novel multi-fuel combustion strategy that is aimed at making aviation fuel agnostic. This is one of the latest endeavours that we are pursuing at TU Delft along with our industrial partners\, Airbus and Safran. \n  \nSpeaker:  Prof. Arvind G Rao \nBiography : \nDr. Arvind Gangoli Rao\, is a Chair Professor of Sustainable Aircraft Propulsion at the Faculty of Aerospace Engineering\, TU Delft. Dr. Gangoli Rao obtained his masters and PhD in aerospace engineering from the Indian Institute of Technology\, Bombay and later worked at Technion\, Israel as a post-doctoral researcher. Dr. Gangoli Rao is a specialist in aircraft propulsion and has worked on a variety of problems related to gas turbines and novel propulsion systems for aircraft\, especially ones dealing with the usage of alternative energy sources. He has authored around 100 publications. Dr. Gangoli Rao has been involved in several EU projects and Dutch funded projects on sustainable aviation along with the industrial partners. He is the Dutch representative International Society of Air Breathing Engines (ISABE). He is also a member of the ACARE (Advisory Committee for Research and innovation in Europe) working group on Energy and Environment.
URL:https://aero.iisc.ac.in/event/multi-fuel-combustion-for-sustainable-aviation/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Arvind.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250307T110000
DTEND;TZID=Asia/Kolkata:20250307T130000
DTSTAMP:20260418T112656
CREATED:20250304T093656Z
LAST-MODIFIED:20250304T093656Z
UID:10000057-1741345200-1741352400@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Studies on Fluid Structure Interactions in Hypersonic Flow
DESCRIPTION:The global thrust towards the development of hypersonic cruise systems for various applications is leading towards slender configurations with lifting and control surfaces which are thin and complaint and face a hypersonic flow. Hypersonic flows are characterized by large flow kinetic energy and momentum\, which manifests into strong shocks\, high temperatures\, and associated effects that can cause coupling between the flow\, structure\, and thermal effects. Therefore\, understanding Fluid-Structure Interactions (FSI) in hypersonic flow gains significance\, and its predictive modelling is necessary to avoid adverse effects in flight. The majority of literature in supersonic and hypersonic FSI  consider low-fidelity modelling using piston theory\, two-dimensional FSI  computations\, and a limited number of experiments on mainly fully clamped flat panels subjected to aerodynamic loads\, including shock-boundary layer interactions at supersonic Mach numbers. Studies on cantilevered panels\, which are template shapes of control surfaces\, at hypersonic Mach numbers are few\, and there is a significant need to obtain experimental data to aid physical understanding\, validate computational tools and methodology and model the hypersonic FSI  phenomena.\n This motivated the study of three different template flat plate experimental models in the hypersonic shock tunnel HST-2 in the Ludwieg  Mode of Operation\, which has 35 ms of test time. The freestream Mach number of M=6.6 is incident upon a) a cantilevered panel placed along the direction of the flow\, b) a cantilevered panel with an impinging shock\, and c) a trapezoidal wing-like shape fixed at the root and placed transverse to the flow. High-speed schlieren imaging and static pressure measurements at specific locations yield information on the flow characteristics. Image tracking methods are used to extract structural deformation\, and accelerometers measure the oscillatory structural response in the presence of hypersonic flow. Complementary two-dimensional numerical simulations in a fully coupled format are conducted for a limited number of cases. Parametric studies are conducted by varying the panel thickness\, angle of attack\, and mass ratio for plain panels and the impinging shock characteristics for the panel with shock impingement. Natural\, free vibration experiments using an impact hammer excitation are first carried out to evaluate the natural structural modal frequencies.\n Great care is taken in designing all experimental models so that the FSI  response can be captured during the short test time. Oscillatory response is captured successfully using the different diagnostic tools.   For a plain cantilevered panel placed at the Angle of Attack of 20 degrees\,  the FSI response is dominantly near the first structural bending mode at a frequency of 89.65 Hz\, which is higher in comparison to the natural frequency of 75.82 Hz. Multiple diagnostic tools and Dynamic Mode  Decomposition analysis confirm these observations. The angle of attack and mass ratio affect the amplitude of oscillations. Varying thickness changes the structural stiffness\, and accordingly\, the oscillations occur at higher frequencies. Higher downstream pressures on the top surface of the panel due to forebody shock first cause the panel to bend away from the flow\, which leads to the formation of expansion fans\,  releasing the pressure and causing the elastic restoring force to bring it back. Complementary two-dimensional FSI simulations showed good agreement with the experiments\, though the magnitude of amplitude was higher due to the 2D nature of the simulation. Shock Boundary Layer  Interaction is significantly affected by the panel’s compliance. There is a 29.6% reduction of the SBLI separation bubble size on a complaint cantilevered panel. The twin effects of a relaxation in pressure gradient and the existence of wall-normal velocities due to a vibrating panel can be attributed to the observed effect. The trapezoidal wing shape exhibited significantly higher magnitudes in the second structural mode.\nThe studies have laid the foundations for deeper investigations using field imaging techniques like 3D-Digital Image Correlation in the future. The experimental database can be used to develop predictive modelling approaches and data-driven modelling.\n\nSpeaker: Ms. Kartika Ahuja \n\nResearch Supervisor: Prof. Srisha Rao M V
URL:https://aero.iisc.ac.in/event/ph-d-engg-studies-on-fluid-structure-interactions-in-hypersonic-flow/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Kartika.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250312T150000
DTEND;TZID=Asia/Kolkata:20250312T170000
DTSTAMP:20260418T112656
CREATED:20250307T064034Z
LAST-MODIFIED:20250307T064034Z
UID:10000059-1741791600-1741798800@aero.iisc.ac.in
SUMMARY:Ph.D.(Engg) : Multi-Agent Pursuit-Evasion and Coverage Strategies
DESCRIPTION:Autonomous agents are increasingly being used to solve many tasks\, deemed complex by humans\, with ease and effectiveness. Two such applications are in defense scenarios and in coverage. This thesis\, therefore\, is devoted towards study of motion planning strategies for autonomous agents in the context of pursuit-evasion problems as well as different coverage problems. The thesis comprises two parts. In the first part\, pursuit-evasion is considered between an evader and one or more pursuers\, all the agents being non-holonomic having turn radius constraints. A partial information setting is considered wherein the agents (evader and pursuer) know about each others’ speed and position but not about their turning capability. The objective in these problems\, where the pursuer is of higher speed but less agile\, is to obtain an evasive strategy. A two-phase evasive strategy is proposed as an effective solution against the pursuers. It is a proximity based strategy. In the first phase\, when the pursuer is beyond a critical distance from the evader\, the latter assumes the worst that the pursuer is holonomic and solves for the best response strategy. This phase is called the Worst Case Scenario Planning (WCSP). When the evader is within the critical range from the pursuer\, the former attempts sharp maneuvers to sidestep the pursuer and extend time of capture. This phase is called the Proximity Based Maneuver (PBM). Dynamic programming is used to solve for the WCSP strategy. In case of multiple pursuers\, the concept of dominance regions is used to obtain the WCSP strategy. Additionally\, the pursuit-evasion problem is extended to a reach-avoid problem where the evader has the dual objective of avoiding the pursuer and reaching a target. This thesis considers the problem of reaching a moving but non-maneuvering target by a turn radius constrained evader in the shortest time. The evader is modeled as a Dubins vehicle and the reaching strategy is deduced by studying the time-to-go properties for different strategies and chronologically checking simple conditions at crossover points. The proposed two-phase evasive strategy is used for avoiding the pursuer. The reaching strategy and the avoiding strategy are linearly combined to obtain the net reach-avoid strategy. Extensive simulation results are provided to corroborate the effectiveness of both the evasive and the reach-avoid strategies. In the second part of the thesis static and dynamic coverage problems are discussed. Inspiration from flocking principles with substantial modifications is used to design a static coverage strategy. This ensures that the covering agents are spread uniformly around the structure while avoiding collision among themselves and with obstacles in the environment. Coverage is addressed for convex and non-convex shapes in 2D and 3D. For dynamic coverage\, concept of Lissajous curves is used to achieve coverage. Dynamic coverage is split into two chapters: coverage of planar regions and coverage of 3D structures. For planar regions\, the boundary of the region is approximated using Fourier series and radial Lissajous curves are generated within the boundary as reference coverage paths. The optimal field-of-view size is analytically determined along with the upper-bound on the time taken for complete coverage. Various extensions of the strategy such as preferential coverage and simultaneous coverage are also discussed. For 3D structures\, an enclosing volume is considered and Lissajous curves are generated on the surface of the enclosing volume. Conditions for complete coverage as well as collision free coverage in case of multiple agents are determined analytically. Artificial potential fields are used to obtain coverage by conforming to shape of the structure. A variety of enclosing volumes are discussed along with diverse applications such as patch coverage\, waypoint coverage\, and coverage of moving structures. Performance metrics are proposed for both static and dynamic coverage problems that helps in ascertaining the quality of coverage. \n  \nSpeaker : Suryadeep Nath    \nResearch Supervisor: Debasish Ghose
URL:https://aero.iisc.ac.in/event/ph-d-engg-multi-agent-pursuit-evasion-and-coverage-strategies/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/SURYADEEP-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250313T150000
DTEND;TZID=Asia/Kolkata:20250313T170000
DTSTAMP:20260418T112656
CREATED:20250311T110524Z
LAST-MODIFIED:20250311T110524Z
UID:10000061-1741878000-1741885200@aero.iisc.ac.in
SUMMARY:Ph.D.(Engg) : Effect of Laser Shock Peening on Residual Stress and Mechanical behaviour of Aluminium alloy AA2219 Friction Stir Weld
DESCRIPTION:Aluminium alloy AA2219 is a precipitation hardenable wrought alloy with copper as a major alloying element. Large-volume propellant tanks of space launch vehicles are manufactured by joining AA2219 aluminium alloy through Friction Stir Welding (FSW) and it is designed optimally to improve the payload capability.  An increase in the strength of the FSW joint results in payload improvement of space launch vehicles. Residual stress is one of the crucial parameters for the design of pressure vessels\, and it is also necessary to mitigate or reduce the same to improve structural margins. The main challenge is understanding the cause of residual stress\, its evaluation\, and mitigation due to the FSW process. Laser shock peening (LSP) is one of the most promising surface modification techniques to improve the performance of weld joints. In the LSP process\, a high-energy laser beam impacts the surface of the specimen and generates ionized plasma by evaporating a thin ablative layer on the specimen. When a high-energy laser pulse passes through the transparent layer and hits the sample\, the thin ablative layer is vaporized and continues to absorb the laser energy resulting in the generation of ionized plasma. Rapidly expanding plasma is entrapped between the specimen and the transparent layer\, generating high surface pressure and propagating into the sample as a shock wave. When the peak pressure exceeds the material’s yield strength\, plastic deformation occurs in the specimen.\n\nThe present work aims to investigate the impact of LSP on residual stress\, microhardness\, global tensile behaviour\, tensile behaviour of various zones (local tensile behaviour)\, stress corrosion cracking behaviour and surface roughness of AA2219 T87 FSW. Surface and through-thickness residual stress were investigated in this work. In as-welded conditions\, tensile residual stress exists in the weld region with a peak value of +123.5 MPa in the Thermo-Mechanically Affected Zone (TMAZ). LSP has significantly affected all the regions of the weld and reduced tensile residual stress to compressive. Longitudinal residual stress is non-uniform through thickness as well as across the weld. Peak tensile residual stress is +160 MPa at the centre of the weld in mid-thickness\, and the LSP process led to a 55% reduction.\n\nAA2219 T87 FSW exhibits a yield strength of 197 MPa and an ultimate tensile strength of 348 MPa at ambient temperature. The LSP process increased the yield strength of the FSW joint by 7 – 14%. A similar increase is seen in cryogenic temperatures also. The increase in the yield strength is due to the strain-hardening effect induced by LSP. The response of different zones of FSW to tensile lading and LSP was investigated using the digital image correlation technique. LSP led to an increase in YS in Weld Nugget and TMAZ. However\, HAZ does not exhibit a significant increase in YS. The LSP process led to an increase in microhardness of 7 – 20%. Single-layer peening has affected < 0.5 mm depth\, whereas three and six layers of peening have influenced a depth of 1.0 mm and more than 2 mm\, respectively. Metallographic study of LSP specimen confirms an increase in dislocation density\, which is the cause for the increase in YS and microhardness.  The LSP process has increased surface roughness in all regions of FSW\, and the increase is substantial in the weld nugget and TMAZ regions. The LSP process has not affected stress corrosion cracking resistance\, irrespective of the number of layers of peening.\n\nIn summary\, a systematic investigation of the effect of LSP on AA2219 T87 FSW joint is carried out using various experimental and characterization techniques and the benefits of LSP are clearly brought out. LSP of AA2219 FSW reduces tensile residual stress and increases YS. This study has also quantified the improvement in YS of various zones of AA2219 FSW due to the LSP. An increase in microhardness was also noticed due to LSP. In addition\, resistance to stress corrosion cracking is not compromised due to LSP. This research outcome will be useful in improving the structural safety margin or reducing the inert mass of aerospace structures and pressure vessels.\n\n\nSpeaker : Dhanasekaran M P\n\n\nResearch Supervisor: Prof. D. Roy Mahapatra
URL:https://aero.iisc.ac.in/event/ph-d-engg-effect-of-laser-shock-peening-on-residual-stress-and-mechanical-behaviour-of-aluminium-alloy-aa2219-friction-stir-weld/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Dhanasekaran.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250317T090000
DTEND;TZID=Asia/Kolkata:20250317T173000
DTSTAMP:20260418T112656
CREATED:20250225T055413Z
LAST-MODIFIED:20250225T055413Z
UID:10000055-1742202000-1742232600@aero.iisc.ac.in
SUMMARY:Workshop on Sustainability
DESCRIPTION:The Society for Shock Wave Research (India )\, Department of Aerospace Engineering is organizing a “One Day Workshop on Sustainability in Aerospace”  on Monday\, March 17\, 2025. The primary objective of this workshop is to delve into recent advancements and future challenges in sustainable aerospace technology.\nThe aerospace sector is experiencing significant growth in both aviation and space access. As environmental and sustainability concerns take center stage\, the need for continued growth and expansion in the aerospace sector becomes more pressing. This workshop aims to bring together students\, academics\, industry professionals\, and global experts to engage in discussions focused on innovative solutions for sustainability in propulsion systems\, aircraft designs\, fuels\, and space systems. Technical experts from TU-Delft\, University of Central Florida\, IISc and startups from the Netherlands and India will be delivering expert talks highlighting the frontline research activity towards sustainability in aerospace systems. Ample opportunities for discussions among community members will enable the spawning of new research directions.\nWorkshop Brochure is attached.\n\nInterested participants\, kindly register for the workshop.\n\nPlease contact srisharao@iisc.ac.in / sumittambe@iisc.ac.in for any clarifications.
URL:https://aero.iisc.ac.in/event/workshop-on-sustainability/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
CATEGORIES:Workshops / Conferences
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/02/WorkshopSustainability.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250317T110000
DTEND;TZID=Asia/Kolkata:20250317T130000
DTSTAMP:20260418T112656
CREATED:20250311T111336Z
LAST-MODIFIED:20250311T111336Z
UID:10000062-1742209200-1742216400@aero.iisc.ac.in
SUMMARY:The longest known insect migration: Fusing Biology with Aerospace Engineering for innovative solutions
DESCRIPTION:The intriguing annual migration of the dragonfly species\, Pantala flavescens\, was reported a century ago.\nThe multi-generational\, transoceanic migration circuit spanning 14000-18000 kms\, from India to Africa is an\n astonishing feat for an insect few cms in size. Wind\, precipitation\, fuel\, breeding\, and the life cycle affect\n the migration\, yet understanding of their collective role in the migration remains elusive. We identify the\n transoceanic migration route by imposing a time constraint emerging from energetics on Dijkstra’s\npath-planning algorithm. Energetics calculations reveal Pantala flavescens can endure 90 hours of steady\n flight at 4.5m/s. We incorporate active wind compensation in Dijkstra’s algorithm to compute the migration\n route from years 2002 to 2007. The prevailing winds play a pivotal role; a direct crossing of the Indian Ocean\n from Africa to India is feasible with the Somali Jet\, whereas the return requires stopovers in Maldives and Seychelles.\n The migration timing\, identified using monthly-successful trajectories\, life cycle\, and precipitation data\,\ncorroborates reported observations. While working on this problem my mind ventured into many different\n applications of engineering\, which are all connected to the transoceanic migration of dragonflies.\nThe applications range from designing airfoils/wings\, sports aerodynamics and wind turbines to developing\n novel spectral accuracy algorithms for numerical simulations. Hence the ideas vary from simple mimicking\n of dragonflies to more complex abstractions arising from the need to understand their flying behaviour.\n\nSpeaker: Dr Sandeep Saha\n\nBiography :\n\nDr Sandeep Saha is an Associate Professor in the Department of Aerospace Engineering\, IIT Kharagpur.\nHe obtained his bachelors and masters degrees in Mechanical Engineering from IIT Kharagpur.\nHe completed his PhD in Mechanical Engineering from Imperial College London. He thereafter worked as  a\nMarie-Curie Experienced Researcher\, CNRS (Laboratoire FAST)\, Orsay\, France. Thereafter he worked as\n an Aerodynamics Engineer\, ALSTOM Power (now GE)\, Rugby\, UK; then as Research Scientist (Fluids)\,\nSchlumberger Gould Research\, Cambridge\, UK; and then as Academic Staff member\, Mechanical Engineering\,\nUniversity of Duisburg-Essen\, Germany (in collaboration with SIEMENS AG). He has worked on a range of\n problems in fluid mechanics and in recent years has focused on Low Reynolds number Aerodynamics\n ranging a broad spectrum of problems like insect flight\, extraterrestrial flight\, respiratory flows and\nwaste heat recovery and sports aerodynamics.
URL:https://aero.iisc.ac.in/event/the-longest-known-insect-migration-fusing-biology-with-aerospace-engineering-for-innovative-solutions/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Sandeep.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250318T110000
DTEND;TZID=Asia/Kolkata:20250318T130000
DTSTAMP:20260418T112656
CREATED:20250311T060827Z
LAST-MODIFIED:20250311T060827Z
UID:10000060-1742295600-1742302800@aero.iisc.ac.in
SUMMARY:Ph.D.(Engg): Investigations on Hypersonic Laminar to Turbulent Boundary Layer Transition in a Shock Tunnel.
DESCRIPTION:The laminar to turbulent boundary layer transition onset has perplexed fluid dynamics community irrespective of the flow regime under which the phenomenon is probed. The complexity of the problem is compounded in high-speed compressible flows where in the transition onset location is a strong function of many subtle factors like freestream quality\, surface roughness\, wall temperature etc. The transitional and turbulent boundary layers bring their typical characteristics\, like an increase in skin friction\, heat transfer\, fluid dynamic parameters fluctuations\, mixing characteristics\, potential to negotiate adverse pressure gradient\, along with them. These typical characteristics of transitional and turbulent boundary layers can be both detrimental and advantageous to a given facet of an aerodynamic vehicle design. Hence the boundary layer transition onset location is one of the key design inputs in the development of aerodynamic vehicles operating in subsonic\, supersonic and hypersonic freestream environment. A plethora of work has been conducted to investigate the transition onset phenomena in supersonic and hypersonic flow regime since the beginning of space age and the inception of the idea of an air breathing hypersonic cruise vehicle. The outcomes of these investigations and studies on high-speed boundary layer transition onset although led to the development of several techniques and correlations to estimate the transition onset location\, applicable usually to a particular test model and freestream condition\, very few studies targeted the characterization of transitional boundary layer in hypersonic flow regime. The earlier and contemporary work on roughness induced transition onset focused on the effect of the said roughness element on transition onset location but the features associated with the instabilities thus generated by these roughness elements have seldom been reported in the open literature. Hence characterization of transitional boundary layer and the instabilities associated with the same was one of the primary objectives of the present work.\nThe present work on hypersonic boundary layer transition was conducted in a shock tunnel HST4 by employing generic test models like flat plate\, cone and elliptic cone. The work began with the design\, development and deployment of a new contoured nozzle\, with a nominal Mach number of 6.0\, for HST4. Before embarking on the boundary layer transition studies\, dedicated efforts were made to characterize the freestream noise environment of the test section of HST4 by employing experimental and numerical methods. A two-dimensional finite difference Navier-Stokes solver was developed in order to numerically compute the transfer functions required to retrieve freestream pressure fluctuations from the experimental measurements. The RMS of pressure fluctuations in the test section of HST4 was found to be 4.32% for the freestream Reynolds number of 4.5 million/m with major contribution of low frequency fluctuations (<50 kHz) towards the aforementioned RMS magnitude. The transitional boundary layer on smooth surface of a flat plate and an axisymmetric cone were characterized by experimentally measuring the intermittency associated with such boundary layers. The intermittent nature of the transitional boundary layer results from the convection of the turbulent spots along the boundary layer. The leading edge and trailing edge velocities associated with these turbulent spots as well as their generation rates were experimentally measured and computed. The second mode instabilities\, a typical characteristic of high Mach number boundary layers\, were also measured in terms of pressure fluctuations and the bandwidth of these instabilities was found to be in the range of 240-480 kHz. The wavelengths associated with these instabilities were found to be 2.5 times the local boundary layer thickness. Transition onset due to the presence of an isolated roughness element\, either a protrusion or a three-dimensional shoe box cavity\, was also investigated as part of the present campaign. Both isolated protrusion and cavity led to an early onset of transition when compared to the smooth test models with no isolated roughness element. In the case of transition onset due to an isolated cubic protrusion\, the Shuttle Orbiter correlations were found to be inadequate in estimating the transition onset and correlations based on the present dataset were formulated. A single frequency oscillation with a narrow bandwidth centered around 23 kHz corresponding to hair pin vortices in the wake of roughness element was found in the present work. It was also found that while the protrusion suppressed the second mode instabilities\, the cavity aided in the development of high frequency instabilities akin to second mode. Finally initial findings of the transition onset due to cross flow instabilities in an elliptic cone were also discussed in the present work. \n  \nSpeaker : Ankit Bajpai \n  \nResearch Supervisor : Prof. Gopalan Jagadeesh
URL:https://aero.iisc.ac.in/event/ph-d-engg-investigations-on-hypersonic-laminar-to-turbulent-boundary-layer-transition-in-a-shock-tunnel/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Ankit-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250319T150000
DTEND;TZID=Asia/Kolkata:20250319T170000
DTSTAMP:20260418T112656
CREATED:20250313T105656Z
LAST-MODIFIED:20250326T050053Z
UID:10000063-1742396400-1742403600@aero.iisc.ac.in
SUMMARY:MTech(Res) : Elastic Wave Dispersion Analysis and Mode Shape Investigation of Higher-order Beam Theory for Thick Beams
DESCRIPTION:The dynamic behavior of structural components over broad frequency ranges\, particularly thick beams under different constraints\, is important in many engineering applications where reduced dimensional modeling is required for design. Applications are aerospace structures\, mechanical systems and civil infrastructure. The rigid cross-section assumption in Euler-Bernoulli and even third-order beam theories cannot accurately capture the effects of stress-free or finite surface conditions and higher-order stress distribution under dynamic situations. While some higher-order beam theories satisfy shear stress boundary conditions\, they do not fully account for normal stress. The higher-order beam theory employed in this study addresses these limitations. It satisfies both shear and normal traction conditions simultaneously. Another problem in guided wave behavior within thick beams is accurately modeling consistent surface or interior dynamics. For this\, the transverse displacement is approximated using a trigonometric variation across the thickness\, characterized by a fundamental wave vector consistent with the necessary stress variation throughout the thickness\, which is particularly relevant for thick structures.\n\nThere remains a lack of comprehensive comparison between different reduced-order models\, particularly in terms of their accuracy in predicting wave dispersion characteristics and dynamic deformation mode shapes in the short and long wavelength limits to evaluate the acceptability of specific models in specific applications. Also\, the choice of beam theory directly influences these properties. This study compares four different theories: Euler-Bernoulli\, Timoshenko\, Third-order shear\, and proposed higher-order theory with surface constraints. The dispersion characteristics of each beam theory are obtained by solving the characteristic equations using the polynomial eigenvalue method\, and dispersion curves are plotted to compare wave propagation behavior predicted by different theories. This comparison highlights the limitations of the lower-order theories\, especially in their ability to accurately capture the behavior of thick beams\, and demonstrates how higher-order theory provides improved predictions of wave behavior.\n\nTwo numerical validation techniques are employed to validate and investigate higher-order wave modes present in higher-order beam theory: one is based on the two-dimensional Fast Fourier Transform (2D FFT)\, and the other uses particle displacement vector plots. In the first approach\, a time-varying excitation is applied to the beam with a specific tonal frequency\, and time-domain response data is collected. The 2D FFT is then performed to extract the dominant wave modes. This method generates the flexural and axial modes at 300kHz frequency as an example\, which is better predicted using the higher-order beam theory. In the second approach\, wave motion is visualized as particle trajectories by plotting displacement components along axial and transverse directions. This method enables the generation of pure wave modes by solving the displacement field directly\, eliminating dependencies on boundary conditions and external excitation. This method validates all mode shapes present in the Higher-order beam theory.\n\nIn summary\, this thesis presents a comparative study of various beam theories to highlight the importance of higher-order beam theories where relevant physics needs to be captured. The dynamic effects are relevant in applications in vibrating machinery\, dynamic contact effects\, bearings\, and advanced contact force-based testing like resonance and force microscopy.\n\n\nSpeaker : Kratika Raje\n\nResearch Supervisor: Prof. D. Roy Mahapatra
URL:https://aero.iisc.ac.in/event/mtechres-elastic-wave-dispersion-analysis-and-mode-shape-investigation-of-higher-order-beam-theory-for-thick-beams/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Kratika-1-1.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250327T100000
DTEND;TZID=Asia/Kolkata:20250327T113000
DTSTAMP:20260418T112656
CREATED:20250321T092005Z
LAST-MODIFIED:20250326T050121Z
UID:10000064-1743069600-1743075000@aero.iisc.ac.in
SUMMARY:Challenges and Strategies for Machining Aerospace High-Temperature Materials
DESCRIPTION:Abstract:\nThe presentation opens with a comparison of high-temperature materials with everyday metals. This will be followed by a discussion of challenges and an understanding of the machinability of high-temperature materials. Next\, various strategies for machining high-temperature materials\, along with practical real-life case studies\, will be presented. We will be introducing the concept of Feed Milling and its advantages. Pocket Milling is among challenging operations\, and we will discuss existing and alternate methods of pocket milling. Finally\, we will discuss the Barrel mill concept for faster profile machining and a few other solutions. \nSpeaker: H R Narasimhan \n  \nBiography:\nH R Narasimhan is currently a Business Development Manager at ISCAR Metalworks\, a multinational metal-cutting tools company affiliated with one of the world’s largest metalworking conglomerates\, the IMC Group (International Metalworking Companies). He has over 25 years of experience in the US Aerospace Industry in Los Angeles\, Oregon\, Seattle\, and Salt Lake City areas\, with several years of experience as National Product Manager for milling and specializing in machining high-temperature materials and composites
URL:https://aero.iisc.ac.in/event/challenges-and-strategies-for-machining-aerospace-high-temperature-materials/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Narasimhan.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250327T150000
DTEND;TZID=Asia/Kolkata:20250327T163000
DTSTAMP:20260418T112656
CREATED:20250327T063920Z
LAST-MODIFIED:20250327T063920Z
UID:10000065-1743087600-1743093000@aero.iisc.ac.in
SUMMARY:Laser Beam Control Through Atmospheric Turbulence
DESCRIPTION:Laser beam is highly affected by prevailing atmospheric conditions and limit the system performance for various applications. The talk mainly covers the cause of optical turbulence\, its effects on laser beam and further discuss the technologies for controlling the beam for enhancing the effectiveness. Two main techniques namely the Tip-tilt correction for maintaining the beam at same position and adaptive optics technology for controlling the phase distortions and thus enhancing the signal strength on the receiver plane will be discussed. The experimental results for long range propagation will also be presented and discussed. \n  \nSpeaker: Dr. Amit Pratap\, Sc F\, CHESS (DRDO)
URL:https://aero.iisc.ac.in/event/laser-beam-control-through-atmospheric-turbulence/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/Amit.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250404T110000
DTEND;TZID=Asia/Kolkata:20250404T130000
DTSTAMP:20260418T112656
CREATED:20250403T043429Z
LAST-MODIFIED:20250407T044613Z
UID:10000067-1743764400-1743771600@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Control of Alternating Flow Phenomena in Transonic Shock Wave Boundary Layer Interactions Over Payload Region of a Generic Launch Vehicle Model
DESCRIPTION:The transonic Mach number regime is a critical phase in the atmospheric ascent of launch vehicles\, where aerodynamic loads peak due to the combined effects of high freestream dynamic pressure and angle of attack. Besides high steady loads\, launch vehicles experience very high levels of pressure fluctuations caused by interactions between the unsteady λ-shock system and the boundary layer – a phenomenon known as Shock Wave Boundary Layer Interaction (SWBLI). These interactions can induce buffet excitation over the payload region\, leading to structural failure as well as control issues. NASA recommends limiting the nose cone semi-angle to 15° to mitigate shock oscillations\, labelling such designs as “Buffet-Proof.” However\, practical constraints such as payload mass & volume\, rocket diameter\, launch-pad limitations\, etc. necessitate the use of larger nose cone angles which are buffet-prone. While SWBLI has been well understood for two-dimensional flows\, data for three-dimensional launch vehicle type configurations is sparse in the literature\, with regard to even the basic understanding of the phenomena. Hence\, there is a need to develop physics-based models to handle SWBLI in practical cases.\nWind tunnel experiments were conducted to evaluate the aerodynamic impact of increasing nose cone angles to 20° and 25° in the transonic Mach number range. These investigations revealed critical flow characteristics such as abrupt jumps in pitching moments at small angles of attack (±4°)\, very high levels of pressure fluctuations\, λ-shock system oscillations\, and the occurrence of destabilizing counter-rotating vortices\, intermittent supersonic and subsonic flows (termed alternating flow phenomena) at specific Mach numbers of 0.90 and 0.94. The present research explores two approaches towards controlling SWBLI. The first involves a passive device\, a front-mounted Aerodisc\, systematically evaluated for the effect of geometric parameters at critical Mach numbers of 0.9 and 0.94 in the range of angles of attack of ±4°. The optimized Aerodisc configuration achieved the maximum noise reduction of 22 dB (Overall Sound Pressure Level\, OASPL). The second approach involves an active flow control technique using a pneumatic counterflow jet. The jet parameters were varied during the tests. Jets with exit diameters of 3 mm and 4 mm operating at a pressure ratio of 3.2 achieved the greatest suppression by nearly 20 dB. Both the passive and active techniques demonstrated that by energizing the boundary layer\, the oscillating shock waves were stabilized\, the counter-rotating vortices removed\, and the upstream travelling Kutta waves associated with the alternating flow phenomena completely suppressed.\nThis research clearly brings out the basic physics of SWBLI and its control for 3-dimensional launch vehicle type configurations at transonic Mach numbers\, highlighting that energizing the boundary layer is the key to control the transonic flow over launch vehicles with large blunt nose-cones. \n  \nSpeaker: Dheerendra Bahadur Singh \n  \nResearch Supervisor: Prof. G. Jagadeesh
URL:https://aero.iisc.ac.in/event/ph-d-engg-control-of-alternating-flow-phenomena-in-transonic-shock-wave-boundary-layer-interactions-over-payload-region-of-a-generic-launch-vehicle-model-2/
LOCATION:CEH Conference Hall- Room No.239\, Second Floor\, Department of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/04/Dheerendra-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250416T150000
DTEND;TZID=Asia/Kolkata:20250416T170000
DTSTAMP:20260418T112656
CREATED:20250407T063952Z
LAST-MODIFIED:20250407T101249Z
UID:10000068-1744815600-1744822800@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Behaviour Modelling of Non-Cooperative Space Objects and Strategies for Decision Support in Space Situational Awareness
DESCRIPTION:In this modern era\, Space is vital for a Nation’s prosperity and without space\, many critical functions would simply stop working. The increasing number of satellite launches in recent times\, is congesting the space environment. Space is also becoming an increasingly contested environment from the perspective of non-civilian applications of satellites. The civilian and non-civilian space applications mandatorily require a complete awareness of the space environment before taking any operational decisions. Space Situational Awareness [SSA] is the comprehensive knowledge of Resident Space Objects [RSOs] which may include satellites\, rocket bodies\, debris\, and the ability to track and understand their behaviour. Space objects can be majorly categorized into two broad types\, cooperative space objects and non-cooperative space objects. A noncooperative space object is defined as a non-friendly object in space and can be perceived as a threat if it performs anomalous maneuvers in space. Modelling pattern-of-life of non-cooperative space objects is an essential requirement of SSA. Maneuvers of non-cooperative satellites is an important event of interest in their life pattern. In this thesis\, we investigate the behaviour of various classes of satellites through data driven modelling. We also study the threat perception from non-cooperative space objects to space assets of our interest. There are four key areas\, in which the thesis has significantly contributed. The first area deals with investigating\, exploring and modelling pattern-of-life of non-cooperative space objects. We have crafted data-driven solution methodologies from time series analysis\, machine learning\, deep learning to suit specific requirements. The second area pertains to the maneuvers of non-cooperative space objects. Identifying them\, helps in analyzing their behaviour. Since there may be numerous non-cooperative space objects and not all maneuvers of non-cooperative space objects may be threatening in nature\, it is essential to segregate routine maneuvers needed by a satellite to maintain its orbit from anomalous and abnormal maneuvers which may be perceived as threat. In this thesis\, we designed an approach to segregate benign and regular pattern-of-life maneuvers of non-cooperative space objects from their orbital data . The routine pattern-of-life maneuvers of satellites are events of interest\, but are infrequent and hence the non-maneuver class was observed to be far more numerous than the maneuver class label in the dataset. Through this thesis work\, we have applied Synthetic Minority Oversampling Techniques (SMOTE) and its variants to handle the imbalance in dataset available for classification. Different missions of cooperative civilian satellites in Low Earth Orbit (LEO) space regime were evaluated to prove the efficacy of the approach. The third area of contribution is in developing methodologies to estimate the threat perception for Geostationary Orbit (GEO) space regime. Modelling pattern-of-life of non-cooperative GEO satellites helps to identify anomalous behaviour and is essential for SSA. Additionally\, given a satellite of interest\, an assessment of the area of influence of neighbourhood satellite operations is critical for assessment of threat. Nearest neighbour search is a fundamental problem in computational geometry and we studied two major concepts of computational geometry \, the Voronoi diagram and the Delaunay triangulation in detail and crafted algorithms to assess threat in the GEO space regime. The last area of contribution is with scheduling the limited and costly ground based sensors to monitor the large number of space objects. There exists a problem of gaps in the available orbital data of noncooperative satellites. Moreover\, the satellite maneuver (event of interest) occurrence information of some samples may be lost\, due to noise in the ground sensor observations or due to observation window limits or losing tracks. Conventional machine learning regression methods are not suited to be able to include both the event and time aspects as the outcome. The conventional models are also are not equipped to handle censored examples (incomplete data due to non-observability). Therefore\, in this thesis\, we devised a solution methodology by applying Time-to-Event data analysis (survival analysis) techniques to assess whether a satellite maneuvered\, that is whether the event of interest occurred or not\, and also estimate when the next maneuver would occur. We have explored a variety of approaches including Cox proportional hazards model\, Weibull distribution model\, Kaplan-Meier model\, Nelson-Aalen model\, Random survival forest\, Survival Support Vector Machines\, Gradient boosted survival analysis and Deep learning based survival analysis. Detailed experimental results based on real life satellite orbital datasets are presented to bring out the effectiveness of the solution methodology. To summarize\, the thesis contributes by developing a space situational awareness system to achieve behavioural modelling\, classification and characterization of space objects of interest\, maneuver classification\, anomaly detection and threat assessment through data driven methodologies. \n  \nSpeaker: Shiv Shankar S  \n  \nResearch Supervisor: Debasish Ghose
URL:https://aero.iisc.ac.in/event/ph-d-engg-behaviour-modelling-of-non-cooperative-space-objects-and-strategies-for-decision-support-in-space-situational-awareness/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/04/SHIV-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250416T153000
DTEND;TZID=Asia/Kolkata:20250416T170000
DTSTAMP:20260418T112656
CREATED:20250416T051419Z
LAST-MODIFIED:20250416T051419Z
UID:10000070-1744817400-1744822800@aero.iisc.ac.in
SUMMARY:Miniaturised technologies for potential applications in space research
DESCRIPTION:Miniaturised technologies\, due to their portability\, rapid responses\, low powers and ability of multi-component integration\, have received an ever-growing interest in areas like healthcare\, air quality\, and space research. This talk will provide an overview of my research in 3 domains of miniaturised technologies: a) microfluidics\, b) MEMS sensors and c) nanoaerosol instruments. I will also highlight areas of space research where this work is potentially relevant. \nI will begin my talk with my work in microfluidic particle enrichment and gene therapy devices. Enrichment devices\, when integrated with a downstream sensor for target particle detection\, can significantly improve the sensor sensitivity. I will cover my work in developing enrichment devices and mitigation of some undesirable effects that can limit their reliability. I will also introduce my work in commercial-scale microfluidic mixers for gene therapy. The work in this theme is highly relevant to healthcare in manned space missions and CubeSats to understand in-space behaviour of bio-species. \nI will next cover my work in thin film MEMS mass sensors\, which offer several advantages over conventional sensors like QCMs thanks to their portability\, high sensitivities and excellent compatibility with semiconductor technology. This talk will cover my work towards enhancing their capabilities in areas of biosensing and simultaneous detection of multiple parameters. This work has a promising applicability in controlling ambient conditions inside spacecrafts\, and healthcare in manned space missions. \nI will conclude with my work in 2 miniaturised nano-aerosol technologies\, namely a) an instrument that can produce a constant number concentration of charged nanoaerosols\, a need unmet in aerosol instrumentation until now\, and b) a sensor that can both count and map the global distribution of airborne ultrafine particles\, a requirement crucial for the upcoming WHO air quality guidelines. The work in this theme has enormous significance in simulating cosmic dust conditions and satellite-based remote sensing of particulate matter distribution near the earth’s surface. \n  \nSpeaker: Dr. Akshay Shridhar Kale \nBiography: \nDr. Akshay Shridhar Kale is a senior postdoctoral affiliate at Trinity College and a teaching assistant at the Department of Engineering at the University of Cambridge\, UK. He is also an Honorary Adjunct Professor at the Department of Mechanical Engineering at COEP Technological University in Pune. His research interests lie in the development of miniaturised technologies and possesses a track record in the areas of microfluidic devices\, MEMS / acoustic devices and nanoaerosol instrumentation. He is also highly active in industry-oriented research and has completed several industrial consultancy projects in his areas of interest. His recent work on integration of miniaturisation principles with nanoaerosol instruments has won him grant funding awards that have partially supported the early stages of commercialisation of a portable nanoaerosol counter in collaboration with a spin-out company from his research group. At COEP\, he is actively involved in developing microfluidics research programs and a proposed centre of excellence in micro- and nano- manufacturing. Along with research and development\, he regularly teaches thermal and fluid science courses at Trinity College\, and has co-guided several undergraduate and Masters students through his research projects across Cambridge and COEP. Dr. Kale earned his B.Tech. in Mechanical Engineering at COEP\, followed by an MS and a PhD in thermal and fluid systems from Clemson University\, USA
URL:https://aero.iisc.ac.in/event/miniaturised-technologies-for-potential-applications-in-space-research/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/04/Akshay-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250423T100000
DTEND;TZID=Asia/Kolkata:20250423T130000
DTSTAMP:20260418T112656
CREATED:20250422T055303Z
LAST-MODIFIED:20250422T055303Z
UID:10000071-1745402400-1745413200@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Navigation of Autonomous Vehicles using Event Cameras and Modified RRT Methods
DESCRIPTION:Autonomous vehicles\, such as unmanned aerial vehicles (UAVs) and autonomous mobile robots (AMRs)\, are at the forefront of technological innovation and are widely used across various applications. As these vehicles become more agile and operate primarily in unstructured environments\, the components of the navigation pipeline must function in real time while optimizing limited onboard computing and memory resources. The challenges faced by a fast-moving vehicle in indoor environments differ significantly from those encountered by outdoor systems. This thesis focuses on autonomous vehicles operating in indoor\, GPS-denied\, and unstructured environments. The algorithms presented address these specific challenges and contribute to the growing body of research on real-time navigation solutions for such scenarios. In this thesis\, we have investigated and addressed various aspects of the autonomous vehicle navigation pipeline. A key focus throughout the work is ensuring real-time performance on edge computing systems. Inspired by the emergence of bio-inspired event cameras\, which offer potential solutions to the limitations of current state-of-the-art algorithms\, the first part of the thesis explores the use of these sensors for perception tasks such as localization and obstacle avoidance. Event cameras provide several advantages\, including motion blur-free data output\, a high dynamic range\, and enhanced low-light sensitivity. These features make them particularly suitable for improving Visual-Inertial Odometry (VIO) systems over traditional frame-based cameras. However\, the sparse and asynchronous nature of event data poses challenges for conventional computer vision algorithms. Existing approaches often convert event streams into image-like representations\, limiting the full potential of event cameras. To overcome these challenges\, asynchronous (data-driven) methods are essential for event-camera-based VIO solutions. The work here introduces an end-to-end data-driven event camera-based Visual-Inertial Odometry (AeVIO) algorithm that updates the system state based on camera velocity. The algorithm performs event feature detection and tracking asynchronously from the event stream and integrates these measurements with IMU data using a structureless Extended Kalman Filter (EKF) to refine state estimates. Given that the data rate of event cameras depends on the scene texture and the relative motion between the object and the camera\, we also explore their application for high-speed obstacle avoidance. Time-to-contact (TTC) is a critical measure estimating the time before collision if the current motion remains unchanged. While event cameras excel at capturing small\, rapid changes\, they lack the detailed scene information that depth cameras provide. We present a novel approach to fuse the low temporal resolution data from a depth camera with the high-speed output of an event camera to compute TTC with obstacles. The proposed algorithm is integrated into the AirSim simulator and evaluated across various dynamic obstacle scenarios\, demonstrating its effectiveness in collision avoidance. The second part of this thesis focuses on the path planning component of the autonomous navigation pipeline. Effective navigation for AMRs and UAVs requires advanced path planning that accounts for kinematic constraints and enables smooth trajectory execution in complex\, cluttered environments. We investigate a probabilistic framework based on the Rapidly Exploring Random Tree (RRT) algorithm\, which incorporates vehicle kinematics to identify the most likely direction for the next node generation. This approach utilizes Gaussian Mixture Models (GMMs) to improve node generation efficiency while addressing optimization challenges in both 2D and 3D spaces. This acts as dynamic bias in the algorithm. Additionally\, we introduce a next-node selection heuristic that directs the search tree expansion toward the goal while avoiding obstacles. To enhance convergence\, we explore methods to discretize both the action and search spaces. Initially\, the method is applied to AMRs and is subsequently extended to the more complex task of 3D path planning for UAVs. In summary\, this thesis contributes to the navigation pipeline by developing simple\, computationally efficient algorithms that leverage event sensors and probabilistic methods. These algorithms are designed to operate in real-time on modern UAVs and AMRs while preserving their agility\, enabling operation in indoor GPS-denied environments\, and accommodating limited onboard computing resources. \n  \nSpeaker: Ankit Gupta \nResearch Supervisor: Debasish Ghose
URL:https://aero.iisc.ac.in/event/ph-d-engg-navigation-of-autonomous-vehicles-using-event-cameras-and-modified-rrt-methods/
LOCATION:Online
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/04/Ankit-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250429T170000
DTEND;TZID=Asia/Kolkata:20250429T183000
DTSTAMP:20260418T112656
CREATED:20250424T044437Z
LAST-MODIFIED:20250424T044437Z
UID:10000072-1745946000-1745951400@aero.iisc.ac.in
SUMMARY:Eulerian-Lagrangian Modeling of Flash-boiling Injection Processes in Internal Combustion Engines
DESCRIPTION:Reducing greenhouse gas emissions from the transportation sector\, especially carbon dioxide\, is one of the main global challenges to achieve a more sustainable future. Developing internal combustion engines with advanced injection and combustion concepts that improve efficiency and decrease pollutant emissions are essential steps towards reducing their environmental impact. Over the past decades\, flash-boiling injection has become a promising alternative to generate a much finer spray compared to high-pressure injection. The rapid phase-change phenomenon during flash-boiling injection occurs due to the superheating of the liquid fuel upon entering the combustion chamber\, resulting in tiny droplets due to the abrupt disintegration of the liquid jet\, which in turn enhances the mixture homogeneity between air and fuel by increasing the vaporization rate\, widening the spray plume due to the increased radial expansion via bubble growth\, and reducing the droplet velocities\, thus leading to shorter penetrations. A detailed understanding of the underlying mechanisms of the flash-boiling process\, such as nucleation of vapor bubbles\, bubble growth\, and finally jet burst\, at a microscopic droplet level is necessary to accurately quantify its effect on the macroscopic spray structure. In this talk\, I will first discuss the modeling of single-droplet flash-boiling behavior using a Lagrangian particle tracking (LPT) technique. Following this\, a novel reduced-order Lagrangian model will be introduced to accurately capture the vapor bubble growth in superheated microdroplets\, accounting for interaction among multiple bubbles. Next\, a simplified nondimensional semi-analytical solution for bubble growth\, based on dimensional analysis of the modified Rayleigh-Plesset equation\, will be presented. This solution offers accurate predictions of bubble growth considering bubble interactions using larger time step sizes\, making it effective for simulating large-scale superheated sprays with numerous droplets under varied conditions. Finally\, a three-dimensional two-way coupled large-eddy simulation of superheated spray case will be discussed\, incorporating the newly developed bubble growth model within the LPT framework. \nSpeaker : Dr. Avijit Saha \nBiography: \nDr.-Ing. Avijit Saha is a postdoctoral researcher at the Center for Aeromechanics Research\, Department of Aerospace Engineering and Engineering Mechanics\, The University of Texas at Austin\, USA. His current research primarily focuses on terahertz time-domain spectroscopy (THz-TDS) for the characterization of plasma properties\, including electron density and collision frequency. In addition to his experimental work\, he is developing a novel Bayesian framework for quantifying uncertainties in measurement data\, with the goal of enhancing the reliability and interpretability of spectroscopic diagnostics. He obtained his Ph.D. in Mechanical Engineering from RWTH Aachen University in September 2023\, making him the youngest individual to receive the doctorate degree from ITV. His dissertation focused on the physics based reduced-order modeling of flash-boiling injection processes in internal combustion engines. Prior to this\, he completed his B.Tech. (Hons.) and M.Tech. in Aerospace Engineering from IIT Kharagpur. He was the first recipient of the distinguished ASME IGTI Student Scholarship in the Aerospace department. His research interests span experimental fluid dynamics\, optical diagnostics\, multiphase flow modeling (DNS\, LES\, reduced-order models)\, combustion instabilities\, high-performance computing\, and their applications in aerospace propulsion systems. He has authored numerous publications in leading international journals and conferences\, earning recognition through several prestigious awards. Among his accolades are the Jang Young Sil Post-doctoral Research Fellowship from Korea Advanced Institute of Science & Technology (KAIST) in 2024\, Post-doctoral fellowship from MIT in 2025\, and his role as Principal Investigator for a high-impact compute-time research project under National High-Performance Computing Center for Computational Engineering Science (NHR4CES)\, Germany. Dr. Saha also serves as a reviewer for several notable journals like Nuclear Technology\, Physics of Fluids\, Proceedings of Combustion Institute\, Atomization and Sprays\, and SAE International Journals.
URL:https://aero.iisc.ac.in/event/eulerian-lagrangian-modeling-of-flash-boiling-injection-processes-in-internal-combustion-engines/
LOCATION:Online
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/04/Avijit-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250430T110000
DTEND;TZID=Asia/Kolkata:20250430T123000
DTSTAMP:20260418T112656
CREATED:20250429T092155Z
LAST-MODIFIED:20250429T092155Z
UID:10000073-1746010800-1746016200@aero.iisc.ac.in
SUMMARY:Electrographic Seizure Detection and Forecasting for People with Epilepsy
DESCRIPTION:About fifty million people worldwide suffer from epilepsy\, a neurological disorder marked by sudden\, recurrent episodes of abnormal electrical activity in the brain\, potentially causing sensory disturbances\, convulsions and/or loss of consciousness. Seizure diaries that record the start and end times of each seizure\, along with associated information are important in the management of the disease. However\, video electroencephalogram (EEG) systems available in epilepsy monitoring units and at home ambulatory monitoring units are bulky and unwieldy for continuously monitoring patients during activities of their everyday life. In this talk\, I will describe ongoing efforts to address this issue by utilizing single channel\, wireless and wearable EEG sensors\, and a machine learning approach to continuously monitor persons with epilepsy to detect and characterize electrographic seizures. In addition to explaining the basic approach to automated seizure analysis\, I will discuss: (1) an approach to generalizing the method so that systems trained on one set of patients can be used to monitor other patients; (2) an approach to enhancing the training of the machine learning system when sufficient amount of data is not available; (3) a probabilistic method for determining the type of seizure; (4) our approaches to converting intermediate\, segment-level decisions to seizure event-level decisions; and (5) a personalized algorithm for seizure forecasting to warn patients of impending seizures. I will illustrate the viability of our algorithms using data collected in a multi-center study. \n  \nSpeaker : V John Mathews \nBiography :  \nV John Mathews is a professor in the School of Electrical Engineering and Computer Science at the Oregon State University and Prof. Satish Dhawan (IoE) Visiting Chair Professor at the Indian Institute of Science\, Bangalore. He received his Ph.D. and M.S. degrees in electrical and computer engineering from the University of Iowa\, Iowa City\, Iowa in 1984 and 1981\, respectively\, and the B.E. (Hons.) degree in electronics and communication engineering from the Regional Engineering College (now National Institute of Technology)\, Tiruchirappalli\, India in 1980. \nHis research interests are in nonlinear and adaptive signal processing and application of signal processing and machine learning techniques in neural engineering\, biomedicine\, and structural health management. Mathews is a Fellow of the IEEE. He has served in many leadership positions of the IEEE Signal Processing Society.
URL:https://aero.iisc.ac.in/event/electrographic-seizure-detection-and-forecasting-for-people-with-epilepsy/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/04/Poster-distinguished-lecture-1_page-0001.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250520T103000
DTEND;TZID=Asia/Kolkata:20250520T120000
DTSTAMP:20260418T112656
CREATED:20250515T052853Z
LAST-MODIFIED:20250515T052853Z
UID:10000074-1747737000-1747742400@aero.iisc.ac.in
SUMMARY:Nonlinear saturation of Mack modes in a hypersonic boundary layer
DESCRIPTION:Some decades ago J. T. Stuart formulated a theory for nonlinear saturation of hydrodynamically unstable modes. He proposed that an unstable mode\, upon gaining sufficient energy\, distorts the mean flow. This mean flow distortion reduces the shear\, thus reducing the inviscid energy production mechanism which eventually results in a saturation of instability. In a hypersonic boundary layer\, Mack modes\, which have an acoustic as well as a vortical structure\, saturate with a different mechanism. In this talk I will present the Mack mode instability saturation mechanism using parallel flow DNS and models. I will also give a brief overview of the other ongoing research activity in my group at IIT Delhi. \n  \nSpeaker: Dr. Prateek Gupta \n  \nBiography : \nDr. Gupta is an Assistant Professor at the Department of Applied Mechanics\, IIT Delhi. He completed his BTech in Mechanical Engineering from IIT Delhi in 2015 and PhD in Mechanical Engineering at Purdue University in 2019. He performed theoretical and numerical investigations of nonlinearities in thermoacoustic systems for this PhD thesis. He later joined the Mechanical and Process Engineering Department at ETH Zurich as a Postdoctoral Fellow\, where he worked on theoretical and computational modeling of non-equilibrium thermodynamics in crystalline materials. He joined the faculty of his alma mater in 2021. Dr. Gupta’s broad research interests span fundamentals and applications of fluid mechanics\, statistical mechanics\, and thermodynamics. \n 
URL:https://aero.iisc.ac.in/event/nonlinear-saturation-of-mack-modes-in-a-hypersonic-boundary-layer/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/05/AE-Seminar.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250603T113000
DTEND;TZID=Asia/Kolkata:20250603T130000
DTSTAMP:20260418T112656
CREATED:20250527T091724Z
LAST-MODIFIED:20250527T091724Z
UID:10000077-1748950200-1748955600@aero.iisc.ac.in
SUMMARY:Space Domain Awareness in the Artemis Era
DESCRIPTION:Since the Apollo era\, space has become an increasingly valuable domain for national security due to diplomatic\, informational\, and economic reasons. The last few years have seen exponential growth in the launch of space objects and there is an increased interest in having a permanent cislunar presence through the Artemis program. The understanding of motion of a spacecraft in multi-body environment is essential to transit between different regions in the cislunar space and to forecast and track objects in the cislunar space. The perturbed two-body restrictive framework has led to extensive modeling\, analysis\, and analytical solutions to study spacecraft motion in orbits around the Earth. However\, beyond GEO (XGEO) the dynamical environment shifts\, and the structure of fundamental behaviors can be radically different. The primary challenge that limits the transferability of tools and techniques from the GEO to XGEO region is non-Keplerian dynamics\, data sparsity from limited coverage and availability of sensors. The process of orbit determination and forecasting the path for an object based on short time arc observations is not trivial. This talk will introduce novel tools to track spacecraft motion in cislunar space and transfers between different regions in cislunar space. These tools make use of dynamical system theory in combination with advances in optimal control theory to provide a better understanding of transport mechanisms in cislunar space. Local orbit elements will be discussed to characterize the trajectories in the cislunar space.\n\nSpeaker : Dr. Puneet Singla\n\nBiography:\n\nDr. Puneet Singla is a Harry and Arlene Schell Professor of the Aerospace engineering at the Pennsylvania State University (PSU). Dr. Singla’s research focus pertains to uncertainty propagation through nonlinear systems\, data driven modelling and control of autonomous systems. His research related honours include the IEEE AESS’s Judith A. Resnik Award\, NSF CAREER award\, the AFOSR Young Investigator award\, the University at Buffalo’s “Exceptional Scholar” Young Investigator Award and the Texas A&M University’s Young Aerospace Engineering Distinguished Alumni Award in recognition of his scholarly activities. He is a fellow of American Astronautical Society (AAS) and an associate fellow of American Institute of Aeronautics and Astronautics (AIAA).
URL:https://aero.iisc.ac.in/event/space-domain-awareness-in-the-artemis-era/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/05/Puneet-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250607T090000
DTEND;TZID=Asia/Kolkata:20250607T173000
DTSTAMP:20260418T112656
CREATED:20250603T101338Z
LAST-MODIFIED:20250604T063640Z
UID:10000078-1749286800-1749317400@aero.iisc.ac.in
SUMMARY:Onboard Trajectory Optimization for System Autonomy on Saturday
DESCRIPTION:Onboard trajectory optimization lies at the heart of true system autonomy\, including UAVs\, Robots\, spacecrafts\, launch vehicles\, missiles\, and so on. Onboard trajectory optimization in real time (optimal guidance) can be generally viewed as a difficult problem. However\, it holds great promise for true system autonomy. The complex interplay between autonomy and onboard decision support systems introduces new vulnerabilities that are extremely hard to predict with most existing guidance and control tools. In this tutorial workshop\, the basic background behind trajectory optimization and computational guidance will be reviewed first. Next\, some recent advances in stabilized continuation techniques for solving two-point boundary value problems with convergence and compute guarantees will be discussed. These concepts further extend for applications to broad classes of trajectory guidance applications for aerospace flight systems including the accommodation of higher-fidelity models through bootstrapping techniques. These technical foundations will be highlighted through illustrative examples for optimal trajectory guidance inside dynamic and uncertain environments. The topics covered will also include an overview of optimal computational guidance with its relevance for challenging aerospace missions. \nLectures:\n1.Overview of Trajectory Optimization (Optimal Control)\n2.Stabilized Continuation for Onboard Trajectory Optimization\n3.Computational Guidance for Aerospace Missions\n4.Bootstrapping Techniques for Onboard Trajectory Optimization \n  \n 
URL:https://aero.iisc.ac.in/event/onboard-trajectory-optimization-for-system-autonomy-on-saturday/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
CATEGORIES:Workshops / Conferences
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/06/slide_for_display-2.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250609
DTEND;VALUE=DATE:20250610
DTSTAMP:20260418T112656
CREATED:20250605T085302Z
LAST-MODIFIED:20250608T033519Z
UID:10000079-1749427200-1749513599@aero.iisc.ac.in
SUMMARY:Koushalya Krushi: Tantra Gnyanada Satva Tatva Workshop
DESCRIPTION:
URL:https://aero.iisc.ac.in/event/koushalya-krushi-tantra-gnyanada-satva-tatva-workshop/
LOCATION:IISc \, Faculty Hall (Main Building)
CATEGORIES:Workshops / Conferences
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/06/AE-Webiste-agri-tech-workshop.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250619T150000
DTEND;TZID=Asia/Kolkata:20250619T170000
DTSTAMP:20260418T112656
CREATED:20250616T090019Z
LAST-MODIFIED:20250616T090019Z
UID:10000080-1750345200-1750352400@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): Compressive behavior of continuous fiber polymer composites in the presence of process-induced defects
DESCRIPTION:The current work examines how process-induced defects influence the compressive behavior of composite structures. The defects analyzed include wrinkles at the macroscale and fiber misalignment at the microscale. Uni-directional carbon fiber-reinforced polymer composites with intentionally created wrinkles were produced by strategically positioning laminate strips. Through comprehensive experimental characterization\, the research thoroughly investigates the impact of wrinkle characteristics and their locations on compressive strength and failure modes. Furthermore\, the study explores how these wrinkle features affect the final kink bandwidth\, angle\, and inclination. Fractographic analysis of the failed specimens identified several damage modes across different length scales\, such as kinking\, delamination\, buckle delamination\, crushing\, fiber pullout\, matrix cracking or failure\, and fiber failure. These findings highlight the importance of considering the geometry of the wrinkles and the various damage modes at different scales when creating a numerical model to accurately predict the compressive behavior of the composite.\nUtilizing the damage modes identified through experimentation\, a three-dimensional repeating unit cell framework is used to investigate how various competing damage mechanisms—such as fiber failure\, matrix plasticity and cracking\, and fiber/matrix debonding—impact the compressive behavior of the composite material. A series of parametric studies is performed to evaluate the effects of factors like fiber volume fraction\, fiber misalignment\, and interfacial properties (including strength\, fracture energies\, and friction) on compressive performance. The results reveal a strong correlation between compressive strength and kink band characteristics with fiber volume fraction\, fiber misalignment\, interfacial shear strength\, interfacial friction\, and matrix cracking. This highlights the necessity of accurately characterizing the mechanical properties and geometric features of the composite constituents.\nTo account for the impact of realistic microstructures on compressive behavior\, a two-step homogenization process has been proposed to reduce computational demands and improve the efficiency of the numerical model. In the first step\, the model captures the homogenized elastic properties and longitudinal compressive behavior. These properties are then used as inputs for a model that consists of multiple domains discretized with Voronoi polygons\, each assigned a specific initial fiber misalignment angle based on a statistical distribution. The homogenized compressive behavior has been validated against previous studies and shows strong agreement. Additionally\, the proposed method has the potential to develop into a multiscale modeling strategy that predicts compressive behavior by considering variations in realistic microstructural characteristics. \nSpeaker:  Shashidhar K \nResearch Supervisor : Prof. Kartik Venkatraman (on behalf of Prof Suhasini Gururaja)
URL:https://aero.iisc.ac.in/event/ph-d-engg-compressive-behavior-of-continuous-fiber-polymer-composites-in-the-presence-of-process-induced-defects/
LOCATION:AE Auditorium
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/06/Shashidhar-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250630T160000
DTEND;TZID=Asia/Kolkata:20250630T170000
DTSTAMP:20260418T112656
CREATED:20250630T060101Z
LAST-MODIFIED:20250630T060101Z
UID:10000081-1751299200-1751302800@aero.iisc.ac.in
SUMMARY:Nature of Phase Kinetics and Memory in Shape Memory Alloys
DESCRIPTION:Shape Memory phenomenon in some intermetallics like NiTi is well known. However\, during arbitrary thermomechanical loading\, these materials exhibit several other interesting\, yet less-understood phenomena. In this talk\, Thermal Arrest Memory and associated effects during interrupted phase transformations in shape memory alloys are discussed and some fascinating underpinnings in the associated martensitic transformations are highlighted.\nThe research talk will be followed by a presentation by the speaker about potential Research and Teaching initiatives and future directions toward collaborative activities at the department. This will include a brief overview of the R&D experience of the speaker over 3 decades\, and a strategy to pursue Research and Development of allied Aerospace technologies and engage with relevant organizations. A brief overview of proposed elective courses like Advanced Aerospace Materials\, and Life-Cycle Analysis and Design of Aerospace systems and components is provided. These are aimed at enhancing the academic level of the students of the department and making them more contemporary. \nSpeaker : Dr. Vidyashankar Buravalla \nBiography :  \nDr. Vidyashankar Buravalla obtained his Ph.D in Aerospace Engineering from IISc in 1998. He has worked in National\, International\, and Multinational R&D entities over the last 3 decades. His areas of expertise include Smart materials and systems\, composite materials and structures\, continuum mechanics\, thermodynamics\, fracture mechanics\, vibration and damping\, NDE and turbomachinery.  He recently superannuated as a Principal Engineer from GE Global Research Center in Bangalore where he worked for nearly 13 years. Prior to that\, he worked in GM R&D for nearly 10 years\, in ADA for 3 years\, and in Rolls-Royce Technology Center in Sheffield UK for 3 years as a Research Fellow. He has 24 Journal and 13 Conference publications and more than 35 technical internal reports. He has 15 patents awarded and more than 30 patent applications under review/processing. He has received several awards in his R&D career and also served as an Adjunct Faculty at IIT-Kanpur between 2008 and 2012. He is associated with several professional bodies and recently served as Hon. President of the Institute of Smart Structures and Systems (ISSS).
URL:https://aero.iisc.ac.in/event/nature-of-phase-kinetics-and-memory-in-shape-memory-alloys/
LOCATION:Auditorium (AE 005)\, Department of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/06/Vidyashankar.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250716T110000
DTEND;TZID=Asia/Kolkata:20250716T130000
DTSTAMP:20260418T112656
CREATED:20250715T041029Z
LAST-MODIFIED:20250715T041029Z
UID:10000083-1752663600-1752670800@aero.iisc.ac.in
SUMMARY:Investigation of flow instabilities in high-speed impinging jets using dual-time velocity measurements
DESCRIPTION:Motivated by applications in the aerospace propulsion industry as well as other energy systems\, the fundamental study of phase-locked shear-layer instabilities in high-speed impinging jets\, has been of research interest for a long time.  The study of instabilities is usually conducted with time derivatives of velocity field. However\, time-resolved experimental data acquisition using particle image velocimetry (PIV) techniques has its challenges for high-speed flows due to the requirements of high spatial and temporal resolution. In this talk\, I will introduce an alternate approach of utilizing time-unresolved dual-time PIV measurements for investigation of the flow instabilities in supersonic impinging jets and illustrate the valuable information about the flow dynamics that can be extracted using the same. \nSpeaker : Dr. Tushar Sikroria \nBiography: \nTushar Sikroria obtained his B.Tech.-M.Tech. Dual Degree in Aerospace Engineering from IIT Kanpur\, Uttar Pradesh\, India\, in 2013. Then he worked for more than two years in John F. Welch Technology Centre\, General Electric (GE)\, Bangalore\, India. Thereafter\, he carried out research work as a Project Engineer in Propulsion Laboratory\, IIT Kanpur\, in 2016\, and later went to pursue his doctoral study from the University of Melbourne\, Australia. He was awarded PhD in Mechanical Engineering from the University of Melbourne\, in December 2021. He pursued post-doctoral research in the Turbomachinery & Propulsion Department\, von Karman Institute\, Belgium and then joined IIT Kanpur as an Assistant Professor in the Department of Mechanical Engineering in January 2024.
URL:https://aero.iisc.ac.in/event/investigation-of-flow-instabilities-in-high-speed-impinging-jets-using-dual-time-velocity-measurements/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/07/Tushar.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250718T150000
DTEND;TZID=Asia/Kolkata:20250718T170000
DTSTAMP:20260418T112656
CREATED:20250715T045641Z
LAST-MODIFIED:20250715T045641Z
UID:10000084-1752850800-1752858000@aero.iisc.ac.in
SUMMARY:Ph.D. (Engg): ON HIGH-SPEED CURVED COMPRESSION RAMP AIR INTAKES
DESCRIPTION:A scramjet\, i.e.\, a supersonic combustion ramjet\, is an air-breathing engine that enables sustained atmospheric flight in the hypersonic regime. It consists broadly of four key components: the air intake\, isolator\, combustor\, and nozzle. The air intake and the isolator collectively comprise the compression system\, which captures and conditions the freestream flow to suit the operational requirements of the combustor positioned downstream. The general set of attributes sought in a high-speed air intake is: low structural weight; low drag; low aero-thermal loads; started flow with high thermodynamic efficiency and high compression ratio; operational robustness to back-pressure fluctuations arising from the combustor; and stable engine operation over a wide flight envelope. The intake flow characteristics and performance are primarily governed by its geometric shape. High-speed air intakes with a curved compression ramp (CCR) are a class of rectangular intakes wherein the compression ramp comprises a curved surface followed by a planar surface tangential to the trailing end of the curved surface. A CCR intake compresses the flow through a combination of a curved ramp shock wave and a series of compression waves. These intake geometries can provide improvements in compression ratio\, pressure recovery\, and allow for a shorter length intake section in comparison to conventional multi-step intake geometries.\nThe present effort consists of the development of a novel analytical framework to model the CCR intake flow and estimate the intake performance parameters at design and off-design operating conditions\, and wind tunnel experiments with a model CCR air intake at Mach 6 to obtain a detailed understanding of the flow dynamics. The analytical framework builds on the principles of mass conservation and the compressible flow theory to model the inviscid flow structure in the intake without any empiricism. A modified Kantrowitz criterion is proposed to examine the ability of a given fixed-geometry CCR intake to spontaneously self-start at the design Mach number. The framework provides a simple\, fast\, and low-cost tool to develop an effective first-cut design of a self-starting hypersonic CCR air intake for any specified set of operating conditions and performance parameters of interest\, such as the startability\, compression efficiency\, and compression ratio. Inviscid flow numerical experiments of intake starting were carried out to preliminarily verify the starting characteristics predicted by the analytical model.\nThe analytical framework was then employed to identify a suitable geometric design point for the experimental CCR air intake model. A self-starting intake test model was designed following the strong shock design principle\, and built for experimentation in the Roddam Narasimha Hypersonic Wind Tunnel at Mach 6 freestream flow conditions. Time-resolved pressure measurements and high-speed schlieren flow visualization were conducted to understand in detail the flow features internal and external to the intake model\, including the dynamics of shock-shock and shock-boundary layer interactions at the cowl and inside the isolator. Performance assessment at design operating conditions involved evaluating the intake’s ability to spontaneously self-start\, in addition to examining pressure recovery and compression ratio of the started intake. At off-design operating conditions\, the intake dynamics were studied by experimentally varying two parameters: intake back-pressure and angle-of-attack (𝛼). In order to mimic combustor-induced isolator back-pressure variations\, a sliding plate was introduced at the isolator exit; the motion of the sliding plate varies the isolator exit area (blockage) and thereby changes the back-pressure. Experimental results showed that the intake auto-reverts to the started state on realizing suitable pressure values at the isolator exit. Coherent flow oscillations with certain characteristic frequencies were observed in the isolator section during the intermediate state of operation (between started and unstarted states). The angle-of-attack (AoA) studies\, in the 𝛼 range of -70 to 20.70\, show that the relatively gradual distribution of adverse pressure along the compression ramp mitigates the risk of large-scale boundary layer separation\, even at very large AoAs. The model intake was found to satisfy shock-on-lip condition and operate in the started state between 𝛼 = 00 and 𝛼 = 100\, and supersonic flow was sustained in the isolator section up to 𝛼 = 20.70. Overall\, the experimental results were found to validate predictions made by the analytical model. The experiments also allowed for a careful examination of flow during various stages of intake operation\, including intake unstart and restart\, and quantification of operational margins (in terms of pressure) for the model intake. In addition to aiding performance assessment\, these results can also form the basis for the design of a practical early-warning system for preventing engine unstart.\nIn summary\, this work offers a clear experimental demonstration of the advantages offered by CCR air intakes\, and an analytical framework that serves as a good starting point for a design exercise. In practical terms\, this work exhibits the promise held by CCR air intake in providing a wide flight envelope for an air-breathing hypersonic flight vehicle. \nSpeaker : Sushmitha Janakiram \nResearch Supervisor : Duvvuri Subrahmanyam
URL:https://aero.iisc.ac.in/event/ph-d-engg-on-high-speed-curved-compression-ramp-air-intakes/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/07/Sushmitha-.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20250721T090000
DTEND;TZID=Asia/Kolkata:20250725T170000
DTSTAMP:20260418T112656
CREATED:20250401T052629Z
LAST-MODIFIED:20250401T052629Z
UID:10000066-1753088400-1753462800@aero.iisc.ac.in
SUMMARY:CISM-IISc Workshop
DESCRIPTION:CISM-IISc Workshop \non \nEmerging Topics in Architectured & Multiscale Materials\, Soft Robotics\,\nand Data-Driven Model Discovery\nDates: July 21–25\, 2025 \nLocation: Aerospace Engineering Auditorium\, Indian Institute of Science\, Bangalore \nAbout the workshop\n\nThe International Centre for Mechanical Sciences (CISM)\, Italy\, and the Indian Institute of Science (IISc)\, Bangalore\, are delighted to announce their first-ever collaboration with the launch of a Joint Advanced Workshop\, marking the beginning of what is envisioned to be an annual series of events. The inaugural workshop\, titled “Emerging Topics in Architectured & Multiscale Materials\, Soft Robotics\, and Data-Driven Model Discovery\,” will be held at IISc. This pioneering event will convene leading researchers\, graduate students\, and professionals from across the globe to explore the latest advancements in the topic. Featuring expert-led sessions\, interactive discussions\, and networking opportunities\, the workshop is designed to foster innovation\, collaboration\, and knowledge exchange\, laying a robust foundation for future editions. We invite you to join us in this exciting partnership as we collectively shape the future of science and engineering. \nFeatured Discussions: \n\nStatic and Dynamic Properties of Architectured Materials\nMultiscale Modeling Through Magnetic Materials\nSlender Structures and Their Applications in Soft Robotics\nData-Driven Material Modeling\n\nLecturers: \n\nAntonio De Simone (The BioRobotics Institute\, Scuola Superiore Sant’Anna\, Italy and Structural Mechanics\, SISSA)\nLaura De Lorenzis (Department of Mechanical and Process Engineering\, ETH Zürich\, Switzerland)\nDiego Misseroni (Department of Civil\, Environmental\, and Mechanical Engineering\, University of Trento\, Italy)\nAkshay Joshi (Department of Mechanical Engineering\, Indian Institute of Science\, Bangalore\, India)\nRajesh Chaunsali (Department of Aerospace Engineering\, Indian Institute of Science\, Bangalore\, India)\nVivekanand Dabade (Department of Aerospace Engineering\, Indian Institute of Science\, Bangalore\, India)
URL:https://aero.iisc.ac.in/event/cism-iisc-workshop/
LOCATION:AE Auditorium
CATEGORIES:Workshops / Conferences
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2025/03/CISM-IISc.jpeg
END:VEVENT
END:VCALENDAR