Momentum Transport in Rotating Shear Turbulence

In turbulent shear flows, the interaction of vortices with a solid surface determines the drag exerted by the fluid. In many practical examples, wall curvature or additional body forces influence the flow and consequently change the drag. Therefore, understanding the connection between the turbulent motion and the drag force (or torque) represents an important task for fluid dynamics research. We study this connection in Taylor-Couette flow, the motion of a fluid between two independently rotating concentric cylinders, which serves as a fundamental model system to analyse the effects of wall curvature and system rotation on the turbulence and angular momentum transport resulting in the torque. Differential rotation, mean rotation and curvature of the cylinders can be varied independently by means of the shear Reynolds number Re_S, rotation number R_Ω and radius ratio η. Because of its large parameter space, the Taylor-Couette flow shows a variety of turbulent phenomena that we study in direct numerical simulations using a spectral method. Furthermore, we introduce physical models to explain the observed turbulent behaviour