Reply To: Water Hammer Valve closing.

[Federico]

Hello, 

if you are using Dynamic meshing, consider this video to get you started: Ansys Fluent: Using the Six Degrees of Freedom (Six DOF) Solver - YouTube

To model closure of the valve, you will need to enable the Gap Model 6.8. Controlling Flow in Narrow Gaps for Valves and Pumps (ansys.com)