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diverge in low courant number

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Old   April 10, 2013, 19:59
Default diverge in low courant number
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Ehsan
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i have set a filling process of a tube.i have set totalPressure and totalTemperature in inlet and tube is closed at other end and flow is compressible.
A shoch should occur that occures but has low resolution and other issue is that this sowewhat simple problem diverges at low courants like .1 with printstack error.but in higher cfl's like .6 doesn't occure an error but continuity residuals goes far away zero in minus direction when the shocks hits to wall and residuals after that return back to zero again.
What may be the cause of this strange behaviour?
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Old   April 11, 2013, 08:41
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my BC's are
p:
Code:
left
    {
        type totalPressure;
            p0 uniform 932190;
            gamma 1.4;
            rho rho;
            //psi none;
            U U;
            phi phi;
            value uniform 303975;
    }
T:
Code:
left
    {
        type totalTemperature;
        T0 uniform 1248;
        gamma 1.4;
       
    }
U:
Code:
left
    {
       type pressureDirectedInletOutletVelocity;
       inletDirection uniform (1 0 0);
       value uniform (300 0 0);
    }
controlDict:
Code:
application     rhoPimpleFoam;

startFrom       latestTime;

startTime       0;

stopAt          endTime;

endTime         0.020708089;

deltaT          5.6e-9;

writeControl    adjustableRunTime;

writeInterval   .000001;

purgeWrite      0;

writeFormat     binary;

writePrecision  10;

writeCompression on;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;

adjustTimeStep  yes;

maxCo           0.6;

maxDeltaT       .0001;

libs ( "libOpenFOAM.so" "libgroovyBC.so" ) ;
and schemes:
Code:
ddtSchemes
{
    default         backward;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         cellLimited leastSquares 1.0;
}

divSchemes
{
    default         none;
    div(phi,U)      Gauss upwind;
    div(phid,p)     Gauss upwind;
    div(phi,K)      Gauss upwind;
    div(phi,h)      Gauss upwind;
    div(phi,k)      Gauss upwind;
    div(phi,epsilon) Gauss upwind;
    div(phi,R)      Gauss upwind;
    div(phi,omega)  Gauss upwind;
    div((rho*R))    Gauss linear;
    div(R)          Gauss linear;
    div(U)          Gauss linear;
    div((muEff*dev2(T(grad(U))))) Gauss linear;
    div(tauMC)  Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;//limited .5
    /*laplacian(muEff,U) Gauss linear corrected;
    laplacian(mut,U) Gauss linear corrected;
    laplacian(DkEff,k) Gauss linear corrected;
    laplacian(DepsilonEff,epsilon) Gauss linear corrected;
    laplacian(DREff,R) Gauss linear corrected;
    laplacian(DomegaEff,omega) Gauss linear corrected;
    laplacian((rho*(1|A(U))),p) Gauss linear corrected;
    laplacian(alphaEff,h) Gauss linear corrected;
    laplacian(k,T)   Gauss linear corrected;  
    laplacian(alpha,e) Gauss linear corrected;
    laplacian(alphaEff,e)  Gauss linear corrected;*/
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default       corrected;//limited .5
}

fluxRequired
{
    default         no;
    p               ;
}
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