Simulating an oscillating wall: uniformFixedValue or movingWallVelocity
 

I am trying to simulate an oscillating wall boundary condition without a moving mesh, so I'm currently using uniformFixedValue BC with a sine and zero offset. However, computing force on the wall is giving a strange result: it never drops below the value it had at t=0, even though the velocity becomes negative. Should I be using a movingWallVelocity BC? Is it even possible to define a moving wall with a sine oscillation?

Note that in my case, it's mostly a normal velocity, like a piston, rather than a shearing flat plate type case.

BC uniformFixedValue for oscilating
 

hello i am looking for BC for uniformFixedValue for an oscillating wall as you specified.

please reply.