Force coefficient oscillations for small timestep
 

Hi everybody,

I'm working with a 3D moving mesh and I've noticed a behaviour in the force coefficients of which I don't know the reason.

The thing is using a time step of 1e-4 s the force coefficients have an oscillating component even though they follow a correct sinusoidal behaviour.
But when I rise the time step to 1e-3 this oscillations disappear.

Why is this happening?

You can view this two behaviours in the picture, before 0.46 s time step is 1e-4 and after this moment it's 1e-3.