free surface modelisation
 

Dear all,

I am trying to model an open channel flow (free surface flow) in a pipe.
The requirement is to obtain the 3D turbulent structure, including turbulence-driven secondary currents.
I have tried innumerable strategies (combined inlet and seperate inlets....) with no luck in obtaining the expected results.
In CCM+, I have defined a field function to fix the water level at the inlet (and used the same for initialization) but the free surface disapears....

Prob definition:
Physics Models:
-Multiphase VOF
-Segregated Solver
-Turbulent -> K-e realiz
-Unsteady flow (Time step = 0.05s)
BC's:
-Combined Inlet: Velocity inlet [Magnitude = 0.5m/s)]
-Outlet: Pressure Outlet
-Turbulence specifications for Inlets and Outlets:
TI = 10%

Please have a look at the problem set up and sugest any change in strategy .

Thank you

I think separate inlets is the best option, or maybe it will work using the flat wave model for combined inlet.
How does the interface disappear?

Have you applied any control to the water level at the outlet?

The water level at the outlet should be a result of the behaviour within the domain. Anyway, the pressure at the outlet should be set according to the expected water level.
Just a stupid question: Did you switch on gravity? Is the mesh fine enough?

yes i switch on gravity,
i put my air with a velocity of 0.5m/s, the same for water.
I attached a picture of the water level at the end of the simulation. I can't attache my report on the original format, my file exceeds the forum's limit . So i put the screenshots

Thanks again,