Relationship between wall shear stresses and streamwise vortices
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The relationship between wall shear stresses and near-wall streamwise vortices is investigated via a direct numerical simulation (DNS) of turbulent flows over a wavy boundary with traveling-wave motion. The results indicate that the wall shear stresses are still closely related to the near-wall streamwise vortices in the presence of a wave. The wave age and wave phase significantly affect the distribution of a two-point correlation coefficient between the wall shear stresses and streamwise vorticity. For the slow wave case of c/Um = 0.14, the correlation is attenuated above the leeward side while the distribution of correlation function is more elongated and also exhibits a larger vertical extent above the crest. With respect to the fast wave case of c/Um = 1.4, the distribution of the correlation function is recovered in a manner similar to that in the flat-wall case. In this case, the maximum correlation coefficient exhibits only slight differences at different wave phases while the vertical distribution of the correlation function depends on the wave phase.
Key wordsdirect numerical simulation (DNS) wall shear stress near-wall streamwise vortex two-point correlation
Chinese Library ClassificationO357.5
2010 Mathematics Subject Classification76F40
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The authors would like to thank Tsinghua National Laboratory for Informa- tion Science and Technology for support in parallel computation.
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