From production to dissipation of Reynolds stress in the turbulent channel flows at high Re

Speaker(s) Myoungkyu Lee University of Alabama at Tuscaloosa
Date 29 March 2022 – 09:00 to 09:30
Venue INI Seminar Room 1
Session Title From production to dissipation of Reynolds stress in the turbulent channel flows at high Re
Chair Beverley McKeon, Moderator: Anagha Madhusudanan
Event [TURW04] Wall-bounded turbulence: beyond current boundaries
Abstract

We investigate the lifecycle of Reynolds stress in the turbulent channel flows at a high Reynolds number. Each term in the Reynolds stress transport equation is spectrally decomposed to uncover the contribution of mean and turbulence at different length scales and wall-normal distances. The streamwise-elongated large-scale structures have important contributions to the production of Reynolds stress in the outer region and transport of Reynolds stress to the near-wall region. In general, inter-scale transfer mechanisms enhance the isotropy in scales and its direction is from large-scale to small-scale except for the near-wall region where inverse energy cascade is observed. The inter-component transfer mechanism exhibits the multi-step behavior when it transfers from streamwise fluctuations to wall-normal and spanwise fluctuations. Finally, dissipation spectra become isotropic, and their scale grows with y^{1/4}.

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