[be89]

Hello,

I'm trying to set up BCs for the case shown in the image 'sideView'.

The case is 2D: water comes from a duct helped by a suction of air (-0.3 bar) and initially fills a tank (outlet initially closed, treated as a wall) till the water reaches a level above the outlet pipe.

Then, the outlet opens and water goes out (while still coming from the inlet).

How should I set BCs for p_rgh and U?


Thank you

[Tobi]

So I think the BC for your inlet and outlet (air) are obvious. The boundary condition for the outlet (water / right bottom) which is depending on other stuff could be set (and have to be set) dynamically. Therefore you have two options. groovyBC (you can use states there - never tried but Bernhard had a talk about his new powerful feature) or you do it with codedMixedBoundary condition. It depend what you want and so on. In order to make it work the system should be:

State Closed

• U is fixed
• p_rgh is a zeroGradient (or flux adjusted like fixedFluxPressure)

State Opened

• U is zeroGradient
• p_rgh is flux based

My opinion. I am not an expert so it might be different to. Any other suggestion is welcomed. Wanna lern too. Even if there are other options to do it.