On The Mechanism Of Attenuation Of Turbulenci by Spanwise Wall Oscillation
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In this work, the mechanism of reduction of wall shear stress caused by spanwise oscillation of a wall is discussed by means of a DNS of a channel flow. For the case of wall oscillation where about 35% reduction in shear stress is attained, the detailed attenuation process of turbulence is discussed. It is demonstrated that the fall of production rate of quasi-streamwise vorticity due to stretching effect is substantial for the phenomenon. The periodical fluctuation of the attitude angle, i.e., the inclination angle to the wall and the slant angle of a vortex to the mean flow, enhances the production. This mechanism is a straightforward extension of the one commonly found in the usual near wall turbulence.
KeywordsWall Shear Stress Direct Numerical Simulation Vortex Line Streamwise Vortex Stationary Wall
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- Brooke, J.W. & Hanratty, T.J. 1993: Origin of turbulence-producing eddies in a channel flow. Phys. Fluids, A5-4 1011–1022.Google Scholar
- Miyake, Y., Ushiro, R. & Morikawa, T. 1995: On regeneration of quasi-streamwise eddies. Proc. 10th Symp. Turb. Shear Flows, Penn.State, Aug.14–16, 1995, pp.15.7–15.12Google Scholar