Single moving reference frame
I have two walls and fluid in between where the upper wall is inclined. The lower wall is moving and the upper wall is stationary. As the lower wall is moving I thought I should use a single moving reference frame. I defined fluid cell zone as moving frame but zero absolute velocity, because I want to see fluid should be dragged because of lower moving wall. And inlet and outlet BC are pressure-driven. My question is as the upper wall is stationary, then should I define simply stationary wall or I should define moving wall with zero velocity.