Numerical simulation of generalized Couette-Poiseuille flow

We present direct numerical simulation (DNS) and modelling of generalized Couette-Poiseuille (GCP) flow in a channel of height 2h defined by three independent parameters (Re,theta,phi). Here (Re,theta) are polar co-ordinates in the space of independent Reynolds numbers (ReC,ReM) associated respectively with the plate velocity difference and fixed volume flow with ReC=Re cos(theta), ReM=Re sin(theta), and phi is the angle between the applied pressure-gradient vector and wall-velocity-difference vector. We will describe DNS of turbulent GCP flow at fixed Re = 6000 with (theta,phi) both in the range zero to 90 degrees. The competition between the Couette-flow shear and the pressure gradient produces a mean velocity profile with directional twist between the confining walls. Results discussed will include four components of the skin friction coefficient with comparison with modeling, mean velocity profiles and pre-multiplied energy spectra.