Good morning every body, I'm a beginner in Ansys and I have some problems in simulating the water reserved upstream and down stream a gate of a regulator (irrigation structure) to study their hydrodynamic effect on the structural elements. The first attached file contains a 1 meter strip of the model which consists of a concrete wall subjected to water on 2 sides with different water levels. I thought that I must add another fluid domain to represent the air above the water at each side to make sure that all the boundary conditions are defined "I'm not sure if this is worthy or not!".The second one is the same strip without the air domain, in this file I tried to simplify the model, but it didn't work too. Now I think I have a problem in defining boundary conditions in fluent, so I'm looking for your help!