Space-time energy spectra for turbulence shear flows

• 主讲人：Guowei He (Institute of Mechanics of CAS)
• 举办方： Beijing-Moscow Mathematics Colloquium
• 时间： 2023-05-19 16:00 - 2023-05-19 17:00
• 地点： online

Recording: https://disk.pku.edu.cn:443/link/69AF81979252F9687C2BA1087CB71CAE
Valid Until: 2027-06-30 23:59

 

Abstract: A space-time (frequency-wavenumber) energy spectrum describes the energy distribution of velocity fluctuations over a broad range of spatial and temporal length scales. It not only characterizes dynamic coupling between spatial and temporal scales in turbulent flows but also plays a key role in turbulence-generated noise. In this lecture, our recent work is introduced on space-time energy spectra and its application to turbulence-generated noise. The Taylor, Kraichnan-Tennekes, and elliptic approximation (EA) models are re-examined in terms of the picture of turbulent passage, which is proposed by Taylor’s frozen-flow hypothesis and the Kraichnan-Tennekes random sweeping hypothesis; The composite resolvent operators are developed for space-time energy spectra; the large-eddy simulation for frequency spectra is used to study the noise radiated by turbulent flows around an axisymmetric body of revolution.

Reference:

1.   He, Jin and Yang, Annu. Rev. Fluid Mech. 49 51-70. 2017

2.   Wu and He, Phys. Rev. Fluids Vol. 6 100504 2021 (APS invited talk)

 

Bio: Dr. Guowei He is a professor and the academic director of the Institute of Mechanics, the Chinese Academy of Sciences. He is an elected Academician of the Chinese Academy of Sciences and a fellow of the American Physical Society. He is the associated editor of the APS journal “Phys Rev. Fluids”. His research interests include turbulence statistical theory and computational modeling, large eddy simulation of turbulence-generated noise and machine learning.