[me45]

Hi,

I'm quite new on OpenFoam and I am using rhoSimpleFoam to get a steady state flow of a supersonic nozzle.

Problem is that I have huge continuity errors and P residuals are high, here are the first and last output of log:

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


SIMPLE: Convergence criteria found
        "(p|U|e|h)": tolerance 1e-05

Reading thermophysical properties

Selecting thermodynamics package
{
    type            hePsiThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleInternalEnergy;
}

Reading field U

Reading/calculating face flux field phi

pressureControl
    pMax 2.46615e+07
    pMin 245803

Creating turbulence model

Selecting turbulence model type laminar
Selecting laminar stress model Stokes
No MRF models present

No finite volume options present

Starting time loop

Time = 10

smoothSolver:  Solving for Ux, Initial residual = 0.000126502, Final residual = 4.31626e-11, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 0.000567908, Final residual = 5.70707e-14, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 1.0017e-05, Final residual = 2.56742e-12, No Iterations 2
smoothSolver:  Solving for e, Initial residual = 6.16089e-06, Final residual = 1.45283e-12, No Iterations 2
smoothSolver:  Solving for p, Initial residual = 0.994916, Final residual = 0.0496945, No Iterations 352
smoothSolver:  Solving for p, Initial residual = 0.0313108, Final residual = 0.012273, No Iterations 1000
time step continuity errors : sum local = 1558.25, global = 877.153, cumulative = 877.153
pressureControl: p min -80834.6
ExecutionTime = 0.1 s  ClockTime = 0 s

    functionObjects::MachNo MachNo writing field: Ma



Time = 1000

smoothSolver:  Solving for Ux, Initial residual = 0.000147395, Final residual = 6.08258e-12, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 0.000566841, Final residual = 6.28291e-13, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 2.53193e-05, Final residual = 7.40255e-13, No Iterations 2
smoothSolver:  Solving for e, Initial residual = 1.84346e-05, Final residual = 6.97073e-13, No Iterations 2
smoothSolver:  Solving for p, Initial residual = 0.989533, Final residual = 0.334296, No Iterations 1000
smoothSolver:  Solving for p, Initial residual = 0.0415304, Final residual = 0.0396437, No Iterations 1000
time step continuity errors : sum local = 30545.9, global = 30254.8, cumulative = 1.56395e+06
pressureControl: p min -1.71007e+07
ExecutionTime = 6.01 s  ClockTime = 6 s

    functionObjects::MachNo MachNo writing field: Ma
End

As I am new, I have taken most of the parameters of fvSchemes/fvSolution on Openfoam's tutorials or on internet.
I have try with really low relaxation factor, otherwise, the simulation crash early.
Initial conditions comes from a simulation done with a transient solver (rhoCentralFoam).

Where does this problem come from?
Does some solvers are better than other for that kind of problem?

Thank you for your help.

controlDict

application     rhoSimpleFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         1000;

deltaT          10;

writeControl    timeStep;

writeInterval   1;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

graphFormat   raw;                                                                                                                                                                                               
runTimeModifiable true;

adjustTimeStep  yes;

maxCo           0.5;

maxDeltaT       1;

functions
{
    #includeFunc MachNo
    #includeFunc residuals
}

fvSolution

 solvers
{
    p
    {   // solver          GAMG;
        solver          smoothSolver;
        smoother        GaussSeidel;
        nSweeps         2;
        tolerance       1e-8;
        relTol          0.05;                                                                                                                                                                                              nCellsInCoarsestLevel  50;                                                                                                                                                                                     }                                                                                                                                                                                                              
    "(U|e)"
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        nSweeps         2;
        tolerance       1e-7;
        relTol          0.1;
    }
}

SIMPLE
{
    nNonOrthogonalCorrectors 1;
    pMinFactor      0.1;
    pMaxFactor      10;

    residualControl
    {
        "(p|U|e|h)" 1e-5;
    }
}

relaxationFactors
{
    fields
    {
        "(p|rho)"               0.001;
    }

    equations
    {
        "(p|U|e)"               0.001;
        "(p|U|e)Final"          1;
    }
}

// ************************************************************************* //

fvSchemes

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;
}

divSchemes
{
    default             none;
    div(phi,U)          bounded Gauss upwind;
    div(phi,e)          bounded Gauss upwind;
    div(phi,epsilon)    bounded Gauss upwind;
    div(phi,k)          bounded Gauss upwind;
    div(phi,Ekp)        bounded Gauss upwind;
    div(((rho*nuEff)*dev2(T(grad(U)))))      Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;                                                                                                                                                                                        }

snGradSchemes
{
    default         corrected;
}

[ishan_ae]

Hello.

Were you able to find a solution to this problem ?