Abstract
We have studied the effects of the moving wall and contraction ratio on turbulence statistics and separation bubble appearing in turbulent Couette and Poiseuille flows over a forward-facing step. The turbulence statistics are obtained by PIV measurements, and are used to specify the difference of the Couette and Poiseuille flows. The experiments were carried out at the contraction ratio of CR = 0.250, 0.375, 0.500 and the Reynolds number of Re_<c0> = 10000 based on the upstream centerline velocity U_<c0> and channel height 2h_1. As a result, separation bubble of Couette flow is smaller than that of Poiseuille flow. The separation bubble grows larger with decreasing the contraction ratio in both flow types.
