Manipulating flow speed at wall

Salman

The fluid velocity at wall use to be 0 for continuum case. But if we want to simulate rarefied gas then we need to specify slip velocity at the wall. One option available is to activate Shear Stress option in wall boundary condition. This way we can get non-zero velocity at wall, but the problem is that this slip velocity is calculated on the basis of the value of Shear Stress provided.

Is there any way to give non-zero velocity at wall using some velocity macro?

Did anybody try this earlier?