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TZID:Asia/Kolkata
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TZOFFSETFROM:+0530
TZOFFSETTO:+0530
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DTSTART:20260101T000000
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DTSTART;TZID=Asia/Kolkata:20261006T143000
DTEND;TZID=Asia/Kolkata:20261006T170000
DTSTAMP:20261011T142818
CREATED:20261005T050831Z
LAST-MODIFIED:20261005T101944Z
UID:10000155-1791297000-1791306000@aero.iisc.ac.in
SUMMARY:M.Tech (Res): Direct Numerical Simulation of Turbulent Aerosol Transport in Human Respiratory Flows
DESCRIPTION:Airborne transmission of respiratory diseases is governed by the coupled dynamics of the exhaled turbulent flow and the transport of pathogen-laden aerosols and droplets. This thesis studies two representative respiratory activities\, speech and cough\, and quantifies the infection probability using Direct Numerical Simulations. The incompressible Boussinesq Navier-Stokes equations are solved using Megha-5 solver\, including the required scalar and dispersed-phase transport equations. Speech flow is studied for a repeated plosive-rich utterance at soft\, normal and loud levels. Aerosol exposure is quantified from the instantaneous and time-integrated flux through a face-sized region representing a silent listener at different streamwise separations. Normal and loud speech develop from individual puffs into a jet-like mean flow\, whereas soft speech remains comparatively underdeveloped. The centreline exposure increases in the approximate ratio 1:5.4:18.4\, governed mainly by the source conditions. At a separation of 1 m\, the infection probabilities are approximately 12%\, 28% and 63% for soft\, normal and loud speech\, respectively. For cough flow\, the existing variable-timescale model is compared with a variable-number-density closure based on the Direct Quadrature Method of Moments. The latter transports droplet number density and total surface area as Eulerian fields and captures strong spatial non-uniformity\, particularly within the toroidal vortex at the puff head. It increases the centreline infection probability by 10-30%\, while a laterally displaced breathing zone produces a non-monotonic variation with distance. The results show that infection risk cannot be described by separation distance alone. The framework provides distance-resolved inputs for room-scale and epidemiological transmission models. \n  \nSpeaker : SUBBA REDDY GARI SHASHANK REDDY \nResearch Supervisor : Sourabh Suhas Diwan
URL:https://aero.iisc.ac.in/event/m-tech-res-direct-numerical-simulation-of-turbulent-aerosol-transport-in-human-respiratory-flows/
LOCATION:AE Conference Room \, AE 003
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2026/10/SUBBA.jpg
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