[rsa]

Hi,


I am trying to learn a bit about the compressibleMultiphaseInterFoam solver to use it later on and build my own case. At the moment I copied the OF6 tut-case (damBreak) with a new geometry with an inlet at the bottom to inject air into a mixture of water and oil with air at the top. I managed to run the case without any problem but there were couple of issues:

1- The results looked very much like the results of incompressible solver multiphaseInterFoam!
2- I looked at the run-time output of the solver and saw the following:
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
This tells me that the solver does not calculate the density which means the density should have been constant; hence, the results looking like the incompressible case now make sense (which is veery confusing since this is suppose to be incompressible)!
3- Then to test further, I commented out the solver for rho in the fvSolution as follows:
".*(rho|rhoFinal)"
{
//solver diagonal;
solver banana;

}
what I expected was for the solver to crash and complain BUT to my supersize, it continued withou any issue!!!
The only thing I could conclude from this is the fact that the solver acts as incompressible and does not calculate the density which according to the info in the CFD Direct webpage the density should be calculated as rho=p/(RT).


I would appreciate if someone can let me know what I am doing wrong or maybe forgetting to do.


In case anyone wants to know the BCs I am using:
U: Inlet flowRateInletVelocity 0.001 / outlet pressureInletOutletVelocity
p: initialized to 1e5 / all the boundaries calculated
p_rgh: initialized to 1e5 / inlet fixedFluxPressure 1e6 / outlet totalPressure 1e5
T: initialized to 293 / inlet fixedValue 293 / outlet inletOutlet (inletValue 293) / walls fixedValue 293 [I intentionally set the system in a isothermal state for simplicity]


Thanks!