Slip-type boundary conditions for turbulent flows over heterogeneous roughness

Turbulent flow over a surface with laterally varying roughness is studied by means of direct numerical simulations (DNS) in a channel. It is known that this configuration gives rise to secondary flows which affect the mean momentum and heat transport. We prescribe spanwise varying wall properties by means of anisotropic slip, which allows to study both ridge- and strip-type roughness without the need for a geometrical representation of the surface structure.