Is it possible to define a moving reference frame with a time dependent velocity ? By the way, can I use sliding mesh with a time dependent velocity ?

Thanks,

Olivier

One can always define a moving reference frame with a time-dependent velocity. Such a frame is referred to as a non-inertial frame, and the acceleration of the frame has to be considered in developing the equations of motion referenced to the moving frame. As long as you account for the appropriate non-inertial effects you can use any frame of reference you want.