A Numerical Study of Turbulent Stably-Stratified Plane Couette Flow

Direct numerical simulations (DNS) of stably-stratified, turbulent plane Couette flow are currently being performed on the XC-4000. The friction Reynolds number is kept approximately constant, Re-tau similar or equal to 540 and the Richardson number Ri(w) varies between 0 and 0.1. The flow is divided into two regions: the region close to the wall and the core region. The region close to the wall presents strong velocity and density gradients and its structure is similar to unstratified wall-turbulence. In the core region, the gradients of mean velocity and density are approximately constant, and the structure of the flow is similar to homogeneous stratified turbulence with shear. With increasing stratification the formation of layers is clearly observed. The layers are inclined with respect to the wall plane and their thickness decreases with increasing stratification.