[ishan_ae]

Hello.


I am simulating subsonic compressible flow through a duct.


I plan to initialize the rhoSimpleFoam solution with that of simpleFoam.


I have a couple of questions for this approach which have confused me and slowed down my progress for quite some time:

1. Would this be he correct way to do things?
   • Solving for turbulence, the usual u,v,w,P and then for T seems correct to me.
2. Since the pressure field solved using simpleFoam is not pressure but kinematic pressure, how can I use this as an input to initialize the rhoSimpleFoam solution?
   • I ask this because for simpleFoam we will solve for kinematic pressure and not pressure. The units are different from that of pressure.
   • Do I need to multiply my simpleFoam kinematic pressure solution with the reference density before I input it to rhoSimpleFoam solver? This sounds complicated to me and I don't know how to do it.
3. Mass flow rate or mass flow rate divided by density for flowRateOutletVelocity ?
   • My setup BC contain totalPressure at inlet and flowRateOutletVelocity. For simpleFoam solving, the flowRateOutletVelocity requires an input for volumetric flow rate and not mass flow rate. I have mass flow rate available with me.
   • At the outlet, I have estimated the density using isentropic flow relations. Would it be wise to divide the mass flow rate with this density, and then specify this as volumetric flow rate to the BC for simpleFoam solution or, should I supply mass flow rate as it is? The latter seems incorrect to me but I am not able to convince myself why so.

Some information on this would be helpful.