[rezvanalamian]

Dear all,
I have a question regarding imposing a boundary condition in ANSYS (Transient Structural).
The problem is a slamming of a composite plate in water (FSI problem). The geometry of the problem is shown in below. The initial velocity of the plate is 10 m/s in the negative direction of the vertical axis. Here, I want to impose a boundary condition for the three orange edges shown in below picture. This boundary conditions should be applied in a way that these edges moves with body but not deflected because of the slamming pressure applied by the water. It means that these edges are actually the fixture frames which carry the plates. On these edges of the fixture-frame, the plate is simply supported without in-plane fixation.
My problem is that I do not know that how I can exert this boundary condition in ANSYS (Transient Structural).

https://ibb.co/q12CVth