fluid Domain without Boundary Conditions

flashpointer · November 12, 2020, 09:54

Hi
i cannot figure out how to define the initial pressures in my case in fluent:
in short we have two chambers, one is closed and filled with compressible gas, the other one with incompressible fluid and comes with an inlet. These chambers are separated with a piston. As we starts to fill the incompressible side, the piston should move and compress the gas chamber with increasing system pressure.
i alredy have an FSI setup with the two faces but how can i defined the initial gas chamber Pressure without BC? and also cannot setup any pressure with only an inlet at the inlet-side.

MKuhn · November 16, 2020, 08:09

With the standard initialization method you can initialize with a certain pressure. Or use hybrid initialization method (in this case fluent will initialize with the operating pressure) and use the patch option to overwrite the pressure settings.

November 12, 2020, 09:54	fluid Domain without Boundary Conditions	#1
flashpointer New Member Join Date: Oct 2018 Posts: 11 Rep Power: 7	Hi i cannot figure out how to define the initial pressures in my case in fluent: in short we have two chambers, one is closed and filled with compressible gas, the other one with incompressible fluid and comes with an inlet. These chambers are separated with a piston. As we starts to fill the incompressible side, the piston should move and compress the gas chamber with increasing system pressure. i alredy have an FSI setup with the two faces but how can i defined the initial gas chamber Pressure without BC? and also cannot setup any pressure with only an inlet at the inlet-side.

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November 16, 2020, 08:09		#2
MKuhn Senior Member Moritz Kuhn Join Date: Apr 2010 Location: Germany, Dresden Posts: 207 Rep Power: 17	With the standard initialization method you can initialize with a certain pressure. Or use hybrid initialization method (in this case fluent will initialize with the operating pressure) and use the patch option to overwrite the pressure settings.