Compressible Flow

I had created a convoluted air flow path through a duct and got good results but when I try to introduce compressibility the operation fails after a while stating;

volume [www.10745.5] RANS Flow: Failed
Unexpected process exit.
[5] Maximum number of iterations exceeded
[5] From function thermo::T(scalar f, scalar T0, scalar (thermo::*F)(const scalar) const, scalar (thermo::*dFdT)(const scalar) const, scalar (thermo::*limit)(const scalar) const) const
[5] in file /home/rjs/projects/of/2.2/OpenFOAM-2.2.x/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.
FOAM parallel run aborting

I left all options as is but I am sure I need to adjust something to make compressible gas work.



Is your Mach number above 0.3?

Compressibility is only worth considering if your flow velocity exceeds a Mach number of 0.3. The incompressible flow solver is much more efficient and robust for flows below this threshold. If your case is likely to be compressible then review the settings for the tutorial "Transonic Flow Over the NACA 0012 Airfoil". Note that you need to precisely specify the reference temperature and pressure to match the conditions you are simulating.