How I can determine the free surface level?

[khadija Rahal]

Hello

My geometry is a prototype of a hydroelectric plant. It consists of a tank, penstock, a gate and a test section; my aim is to simulate turbulent flows on this prototype. My geometry consists of two zones, a zone filled with water (red color) and a zone filled with air (blue color). The water will start to flow when I pull the gate to the top. At first, I want to know what boundary conditions I should give to this geometry and what boundary conditions I should give to the gate. Do I have to use a dynamic mesh to give a motion to this gate and which UFD example should I use?

Secondly, can I consider this geometry as an open channel? If yes, how I can determine the free surface level and the bottom level at outlet?

Sorry for my English.

Can you help me please? Thanks

 

[Baluncore]

There needs to be a gate valve at the turbine input to control the flow through the turbine. That gate and turbine restricts the flow and so allows the penstock to remain full of water during operation.

The gate at the top of the penstock will not need to be closed except when servicing the bottom gate or the penstock.

After the gate at the top of the penstock there needs to be an open vertical pipe, reaching higher than the top of the tank. That will allow air to enter the penstock without restriction when the upper gate is closed. It will prevent the embarrassing partial vacuum collapse of the penstock structure if the upper gate is closed before the lower gate.

 

[CivilSigma]

No, you cannot consider this as an open channel flow because the water is flowing in a pipe.