Mean and turbulence structures of Couette-Poiseuille flows at different mean shear rates in a square duct

摘要

Turbulent Couette-Poiseuille flows inside a square duct at bulk Reynolds number 9700 are investigated using the large eddy simulation technique. Suppression of turbulence intensities and a tendency towards rod-like axisymmetric turbulence state at the wall bisector near the moving wall are identified. The turbulence generated secondary flow is modified by the presence of the top moving wall, where the symmetric vortex pattern vanishes. The angle between the two top vortices is found to correlate with the ratio of moving wall velocity to duct bulk velocity.