[Joe Cor]

I would like to make a new version of chtMultiRegionFoam that is fully compressible -- that is, caculates density as a function of temperature and pressure. Is there anyone who has done this or who could explain how it could be done?

[Tobi]

Hi Joe,

chtMulti is already for compressible fluids.

    tmp<fvVectorMatrix> UEqn
    (
        fvm::ddt(rho, U)
      + fvm::div(phi, U)
      + turb.divDevRhoReff(U)
       ==
        fvOptions(rho, U)
    );

As you see, the density is already included and based on the thermodynamic model you are using, the density is evaluated. For an ideal gas, the density would be calculated based on T and p. The flux fields are also build with the density:

                linearInterpolate(rhoFluid[i]*UFluid[i])
                    & fluidRegions[i].Sf()

The only thing is that the pressure equation is not build for high-speed flow. Here you may have to change the pressure coupling and flux corrections. But there I do not know how to do it.

[Joe Cor]

Thanks for the help.