HI, I am trying to model a water film that flows downwards on a wall surface and then hits a horizontal obstacle to change direction. For the boundary conditions: The water fim has a inlet velocity of -0.13 m/s in y-direction and 0 in x-dir, and 0 in pressure. At the outlet, it has a velocity of d.1/d.2 * 0.13 m/s i x-dir and 0 i Y-dir and 0 pressure. D.1 and d.2 are the width of the film at inlet an outlet respectively. For the boundary between the waterfilm and the wall, there is no slip and no velocity in x and y-drections. For the boundary between the water film and the ambient air: exposed to the external air pressure (p=0) (open ”Gortex-like” membrane that holds the water in place but has no friction.) The water film can take no shear stresses. To be known : pressure distribution in corner area, where the water film change direction. I have a very simple model now but I do not feel that it is the correct one. ma main question is about how to define the boundary condition between the water film and the ambient air, as described obove. Any suggestions ? (For a more proper description, please take a look at the ppt attached.)
Thanks in advance! Best regards Ali