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The School of Engineering, Applied Science, and Health presents its MMAE 593 seminar series featuring guest speaker Rahul Deshpande, assistant professor of aerospace engineering at RMIT University, Melbourne, who will present “Wall-Pressure Measurements at High Reynolds Numbers: Resolving the Lowest Wavenumbers and the Highest Frequencies.” This event is open to the public and will take place on Wednesday, November 18, from 12:45–1:45 p.m. in the Rettaliata Engineering Center auditorium (RE 104).

Abstract

Turbulent wall-pressure fluctuations play a critical role in flow-induced noise and structural loading in applications ranging from aircraft and submarines to wind turbines. Predicting these effects requires accurate measurements and models of the wall-pressure field across a broad range of scales and Reynolds numbers (Re_\tau). However, resolving its lowest wave numbers, associated with large-scale inertia-dominated motions, and its highest frequencies, associated with the small viscous scales, presents major experimental challenges, particularly at high Reynolds numbers. This talk presents two bespoke measurement campaigns in smooth-wall, zero-pressure-gradient turbulent boundary layers spanning 10^3 < Re_\tau < 10^4, designed to overcome these experimental challenges. The first uses a single microphone in the large Melbourne wind tunnel to unravel the Reynolds-number evolution of fully resolved wall-pressure frequency spectra and higher-order statistics. The second uses a microphone array in the TU Delft wind tunnel to resolve the wall-pressure frequency–wavenumber spectrum at the lowest energetic wave numbers. Together, these complementary datasets reveal correlations between velocity and wall-pressure fluctuations across a broad range of scales and spanning a decade in Reynolds number.

Biography

Rahul Deshpande is a lecturer (tenure-track assistant professor equivalent) in aerospace engineering at RMIT University, Melbourne, and is currently based at Princeton University as a Fulbright Scholar from Australia. Supported by an RMIT Vice-Chancellor’s Fellowship awarded in 2026, his ongoing research examines turbulent flows in the near-surface atmosphere and the built environment. Rahul holds bachelor’s and master’s degrees from the Indian Institutes of Technology (IITs) and earned his Ph.D. from the University of Melbourne, specializing in wall-bounded turbulent flow experiments. This work culminated in a university-funded Melbourne Postdoctoral Fellowship (2023–2026) supporting his recent publications on wall-pressure measurements, non-canonical wall flows, and active and passive drag-reduction strategies. These advancements were driven by leading collaborative projects and supervising students across the University of Melbourne, TU Delft, KTH Stockholm, and the University of Bologna.