Abstract

In shear flows with spanwise system rotation, i.e. when the rotation axis is parallel with the direction of the mean flow vorticity, even small rotation rates can lead to drastic changes of the flow, both with respect to the stability of the laminar flow as well as the structure and behaviour of turbulence. Depending on the direction of rotation with respect to the mean vorticity direction the flow is either stabilized or destabilized. The problem is governed by two parameters, namely the rotation number and the Reynolds number. In plane Couette flow the mean vorticity direction is the same across the full channel width, in contrast to for instance pressure driven plane Poiseuille flow for which the mean vorticity changes sign on the channel centreline. In this talk we focus on some flow visualization experiments of plane Couette flow and describe a number of flow states occurring in the parameter plane spanned by the Reynolds number and the rotation number. Some comparisons with plane Poiseuille flow and curved channel (Dean) flow are also made.