Acoustic tones in the near field of a Mach 0.9, Reynolds number 10^6 round jet are investigated using large-eddy simulations (LES) performed with the explicit filtering LES (EFLES) approach. The jet is issued into the ambient through a cylindrical nozzle. Pressure spectra at observer locations in the upstream direction reveal the presence of tones which […]
The need to decarbonize power generation and aviation has established hydrogen as a promising fuel for next generation gas turbine combustion systems. However, its high chemical reactivity significantly increases the propensity for autoignition and flashback under lean premixed conditions commonly used in hydrocarbon combustion systems. New combustor concepts based on direct fuel injection address these […]
Autonomous navigation is becoming a critical capability for modern deep space exploration, planetary defense, and commercial space ventures. Traditional spacecraft navigation relies heavily on ground-based radio contact to collect two-way radiometric Doppler and range measurements. However, this structural dependency introduces significant communication latency and places a heavy burden on oversubscribed ground antenna networks. For cutting-edge […]
An understanding of the flame transfer function (FTF) is essential for predicting the onset of combustion instabilities in gas turbine combustors, where flow oscillations excited by acoustic forcing drive burning area and heat-release oscillations that can couple unfavourably with combustor acoustic modes. The heatrelease response is expensive to characterize directly through time resolved simulation, motivating […]
Robotic swarms offer immense potential for critical operations such as search and rescue, surveillance, and environmental monitoring, owing to their distributed nature and redundancy. However, the operational reliability of swarms heavily depends on a continuous, closed-loop process: extracting high-fidelity or accurate collective situational awareness from distributed observation, and subsequently utilizing that awareness for cooperative decision […]
This talk presents a comprehensive overview of advanced fluidic and thermal management strategies across biomedical and defense applications. We begin with a systematic evaluation of Particle Image Velocimetry (PIV), specifically addressing the challenges of simultaneous velocity and particle size measurement. By analyzing Gaussian intensity variations across the light sheet and the optical system’s depth of […]
Gaseous and particulate pollutants pose a significant threat to human health and the environment, prompting regulatory action to address major sources of emissions. Soot is a key particulate pollutant. Recently, emission standards for commercial aeroengines have been revised, necessitating the mitigation of soot emissions. Investigating the soot formation process is a key step towards reducing […]
Hypersonic propulsion systems capable of sustained atmospheric flight are critical enablers for future reusable launch vehicles, long-range high-speed transport, and responsive global strike platforms. Among the various air-breathing concepts, scramjet engines offer unmatched efficiency at hypersonic speeds by utilizing atmospheric oxygen and avoiding the mass penalties associated with onboard oxidizers. However, the practical realization of […]
Abstract: The Net Zero Emissions 2050 (NZE 2050) initiative sets an ambitious target to eliminate net CO2 within the next two decades. Achieving this goal demands widespread decarbonization across energy, transportation, residential, and industrial sectors. Carbon-free and carbon-neutral fuels are central to this effort. Hydrogen, an abundant, high-energy-density, carbon-free fuel is expected to play a […]
Multi-agent systems are increasingly deployed in missions involving large-scale tasks with complex objectives that are beyond the capability of a single agent. Such missions demand computationally efficient coordination strategies that ensure safety, reliable operation, and ease of implementation, particularly in dynamic and uncertain environments. This thesis investigates coordination strategies in multi-agent systems, specifically addressing the […]
A comprehensive investigation of the energy and enstrophy cascade in physical space in a turbulent channel flow is presented for four Reynolds numbers. Bandpass filtering techniques are employed to isolate scales and quantify inter-scale interactions through kinetic energy flux, enstrophy generation, and enstrophy flux. Two bandpass filter formulations used in the literature are quantitatively assessed by comparing the output. The mean energy and enstrophy cascades are shown to be predominantly local for all the Reynolds numbers. Away […]
Innovative high-performance structural designs play a critical role in mitigating insecure events such as low-velocity and ballistic impacts. These events involve significant kinetic energies, requiring structures that are lightweight, safe, and capable of absorbing energy effectively. Closed cell metallic foams have been widely adopted in aerospace, marine, civil, mechanical, and automotive industries due to their […]
