Influence of a Spanwise Rotation Upon the Coherent-Structure Dynamics in a Turbulent Channel Flow
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We introduce a spectral-dynamic model, which is based on Kraichnan’s spectral eddy-viscosity (Kraichnan, 1976) with an arbitrary spectral exponent m for the kinetic-energy spectrum at the cutoff. This model is validated for LES of a turbulent channel flow at low and high Reynolds numbers. Afterwards we look at the influence of a rotation Ω of spanwise axis at a high rotation rate. We find that the following results, concerning the anticyclonic side of the channel and compared with the non-rotating case : a) the low-and high-speed streaks are reduced ; b) the longitudinal vorticity is increased ; c) the mean velocity profile is linear and equal to 2Ω; d) the organized vortices are more coherent, and preferentially inclined at 25° (instead of 45°) to the wall.
KeywordsDirect Numerical Simulation High Reynolds Number Coherent Motion Turbulent Channel Flow Hairpin Vortex
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