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pimpleFoam screwed up with residual and courant number

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Old   May 1, 2019, 14:29
Default pimpleFoam screwed up with residual and courant number
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Joe lee
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I was trying to use pimpleFoam to obtain the transient solution of my simulation. In fvSolution, I followed: https://openfoamwiki.net/index.php/O...hm_in_OpenFOAM to setup.
And when I had my first timestep, the residuals went crazy. Here is the residuals plot just after the first timestep(50 iterations):


The velocity residuals blew up.

Also, in log.pimpleFoam, I found
1. forceCoeffs blew up;
2. courant blew up;
3. PIMPLE: Not converged within 50 iterations
4. last iteration take 1000 iterations for velocity
Here is part of the log:
Code:
...
PIMPLE: Iteration 49
smoothSolver:  Solving for Ux, Initial residual = 0.2628474, Final residual = 0.006348619, No Iterations 1
smoothSolver:  Solving for Uy, Initial residual = 0.3153633, Final residual = 0.009944488, No Iterations 1
smoothSolver:  Solving for Uz, Initial residual = 0.2931374, Final residual = 0.009416199, No Iterations 1
GAMG:  Solving for p, Initial residual = 1.737072e-05, Final residual = 9.476295e-08, No Iterations 4
time step continuity errors : sum local = 0.0003989904, global = 4.242985e-07, cumulative = 5.625885e-07
PIMPLE: Iteration 50
smoothSolver:  Solving for Ux, Initial residual = 0.6357956, Final residual = 0.0001464525, No Iterations 1000
smoothSolver:  Solving for Uy, Initial residual = 0.7345522, Final residual = 8.67146e-05, No Iterations 1000
smoothSolver:  Solving for Uz, Initial residual = 0.7207067, Final residual = 7.978962e-05, No Iterations 1000
GAMG:  Solving for p, Initial residual = 0.1127675, Final residual = 8.968816e-08, No Iterations 55
time step continuity errors : sum local = 0.004213623, global = -0.001068937, cumulative = -0.001068374
smoothSolver:  Solving for epsilon, Initial residual = 1, Final residual = 0.1651915, No Iterations 1000
smoothSolver:  Solving for k, Initial residual = 1, Final residual = 9.930172e-07, No Iterations 81
PIMPLE: Not converged within 50 iterations
ExecutionTime = 3608.8 s  ClockTime = 3653 s

forceCoeffs forceCoeffs1 write:
    Cm    = -1.194991e+17
    Cd    = -1.60657e+17
    Cl    = 1.946065e+17
    Cl(f) = -2.219587e+16
    Cl(r) = 2.168024e+17

Courant Number mean: 242261.2 max: 6.091332e+10
deltaT = 2.897077e-13
Time = 0.00588235
my questions are:
1. Why would my courant number go so large? I should have limited it in controlDict:
Code:
maxCo		3;
maxDaltaT	1;
2. Is 50 nOuterCorrector too few for this case?

3. Is any of my setup got wrong?(I will post it at the end)

Thank you very much!!

fvSolution:
Code:
solvers
{
    p
    {
        solver          GAMG;
        smoother        DICGaussSeidel;
        tolerance       1e-7;
        relTol          0.01;
    }

    pFinal
    {
	$p;	
	relTol		0;

    }

    "(U|k|epsilon)"
    {
	solver		smoothSolver;
	smoother	symGaussSeidel;
	tolerance	1e-06;
	relTol		0.1;
    }

    "(U|k|epsilon)Final"
    {
	$U;
	tolerance	1e-06;
	relTol		0;
    }
}


PIMPLE
{
	nOuterCorrectors	 50;
	nCorrectors		 1;
	nNonOrthogonalCorrectors 0;

	outerCorrectorResidualControl
	{
		U
		{
			tolerance	1e-5;
			relTol		0;
		}
		p
		{
			tolerance	5e-4;
			relTol		0;
		}
	}
}


relaxationFactors
{
    fields
    {
	p	0.3;
	pFinal	1;
    }

    equations
    {
	"U|k|epsilon"	0.3;	
	"(U|k|epsilon)Final"	1;
    }
}
controlDict:
Code:
application     pimpleFoam;

startFrom       latestTime;

startTime       0;

stopAt          endTime;

endTime         400;

deltaT          0.005;

writeControl    adjustableRunTime;

writeInterval   0.1;

purgeWrite      0;

writeFormat     binary;

writePrecision  7;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable yes;

adjustTimeStep	yes;

maxCo		3;
maxDaltaT	1;

functions
{
    #include "streamLines"
    #include "cuttingPlane"
    #include "forceCoeffs"
}
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