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Turbulence and Aeroacoustics in High-Speed Jets

AMS Seminar Series

Speaker: Sanjiva K. Lele, Stanford University

Presentation

Seminar Slide Deck (PDF-19MB)

Abstract

Engineering applications such as high-speed propulsion or supersonic/hypersonic aerodynamics require accurate predictions of compressible turbulent flows. To improve engineering models for these applications it is helpful to separate variable-density or variable fluid property effects, which dominate the turbulence behavior in supersonic and hypersonic turbulent boundary layers from intrinsic compressibility effects associated with pressure-induced volume change. Highlights from a recent study of compressible shear layers1 are used to stress the close coupling between turbulence and acoustics in such flows, including in high-speed jets. The discussion is then expanded to the problem of predicting the noise radiated by high-speed turbulent jets at pressure-matched and mismatched conditions. Results from recent work using large eddy simulations2,3 are analyzed to characterize the modeling issues faced in predicting turbulent mixing noise, broadband shock-associated noise and jet screech.

[1] Matsuno, K. and Lele, S. K. (2021) J. Fluid Mech. Vol. 907
[2] Bres, G. A. and Lele, S. K. (2019) Phil. Trans. Roy. Soc. A 377:20190081
[3] Wu, G. J., Lele, S. K. and Jeun, J. (2020) CTR Annual Briefs

Biography

Photo of Sanjiva K. Lele
Speaker Sanjiva Lele is a professor in both Aeronautics and Astronautics and Mechanical Engineering Departments at Stanford University. He received his B. Tech. from IIT Kanpur, India and his Ph.D. from Cornell University. His research combines numerical simulations with physical modeling to study fundamental unsteady flow phenomena, transition and turbulence in high-speed flows, and aeroacoustics. Lele is also interested in developing high-resolution computational methods and reduced order modeling. He is a fellow of APS and an Associate Fellow of AIAA. He received the AIAA Aeroacoustics Award in 2016, Distinguished Alumnus Award from IITK in 2016, and best paper awards for joint work with students: from AIAA in 2018, 2015, 2012 and 2011; from ASME in 1999; and SAE in 1998. From 1994-2004 he served as Associate Editor for the Journal of Fluid Mechanics. He is currently Associate Editor for Physical Review Fluids.