[woodie]

Hello everybody,

I am currently trying to do a transient simulation of a wind turbine rotor blade in a single reference frame (SRF) using SRFPimpleFoam (OF-v2112 and v1912).
Before, i already managed to get a steady-state solution using SRFSimpleFoam.
However, as i start SRFPimpleFoam, the values for the pressure go through the roof immediately (the solver keeps running though, but produces an unphysical solution).
I have all the same Mesh and BC as in the steady case, so i really dont understand why these problems occur at all.

Maybe someone has an idea why this is the case.

I will provide more details about my case below.



General Setup:
- 120°-domain in a SRF (see. Fig.1)
- cyclicAMI on rotational symmetry planes (side_left, side_right)
- initialized with the results obtained with SRFSimpleFoam
- Turbulence Model: SSTLM


The Problem:
- extremely high pressure, already after first iteration
SRFSimpleFoam gives values for pressure between -5e3 and 2e3, after the
first time step of SRFPimpleFoam i get values between +-2e8. -> see Fig.2
- rest of the fields does not seem to be affected
- seems like the cyclicAMI patches could be the problem?


Things i changed compared to steady case:
- controlDict:

application     SRFPimpleFoam;
startFrom       latestTime;
deltaT            1e-8;

- fvSchemes: ddtScheme = Euler
- fvSolution:
I also have tried having more OuterCorrectors and control the loop with residualControl.

PIMPLE
{
    momentumPredictor yes;
    nNonOrthogonalCorrectors 2;
    nOuterCorrectors    3;
    nCorrectors         3;
    consistent          yes;
    pRefCell            0;
    pRefValue           0;
    turbOnFinalIterOnly         false;
    correctPhi          true;
...
}

The log-file for the first iteration:

Create time

Create mesh for time = 0


PIMPLE: max iterations = 3
    field p	: relTol 0, tolerance 0.0001
    field Urel	: relTol 0, tolerance 1e-06
    field "(k|omega|ReThetat|gammaInt)"	: relTol 0, tolerance 1e-06

Reading field p

Reading field Urel

Reading/calculating face flux field phi

AMI: Creating addressing and weights between 59136 source faces and 55552 target faces
AMI: Patch source sum(weights) min:0.999999 max:1 average:1
AMI: Patch target sum(weights) min:0.999986 max:1 average:1
Creating SRF model

Selecting SRFModel rpm
Selecting incompressible transport model Newtonian
Selecting turbulence model type RAS
Selecting RAS turbulence model kOmegaSSTLM
Selecting patchDistMethod meshWave
bounding k, min: 0 max: 946.983 average: 2.30207
    Employing decay control with kInf:kInf [0 2 -2 0 0 0 0] 6.5e-05 and omegaInf:omegaInf [0 0 -1 0 0 0 0] 16.36
kOmegaSSTLMCoeffs
{
    a1              0.28;
    b1              1;
    c1              10;
    F3              no;
    ca1             2;
    ca2             0.06;
    ce1             1;
    ce2             50;
    cThetat         0.03;
    sigmaThetat     2;
    lambdaErr       1e-06;
    maxLambdaIter   60;
    decayControl    yes;
    kInf            6.5e-05;
    omegaInf        16.36;
    alphaK1         0.85;
    alphaK2         1;
    alphaOmega1     0.5;
    alphaOmega2     0.856;
    gamma1          0.555556;
    gamma2          0.44;
    beta1           0.075;
    beta2           0.0828;
    betaStar        0.09;
}

No finite volume options present

Starting time loop

forces forces:
    rho: rhoInf
    Freestream density (rhoInf) set to 1.225
    Not including porosity effects







Courant Number mean: 1.75657e-06 max: 0.20131
Time = 1e-08

PIMPLE: iteration 1
DILUPBiCGStab:  Solving for Urelx, Initial residual = 3.61499e-11, Final residual = 5.13285e-33, No Iterations 4
DILUPBiCGStab:  Solving for Urely, Initial residual = 4.49548e-10, Final residual = 1.59125e-31, No Iterations 4
DILUPBiCGStab:  Solving for Urelz, Initial residual = 5.0328e-11, Final residual = 6.55993e-33, No Iterations 4
GAMG:  Solving for p, Initial residual = 0.999989, Final residual = 0.0082096, No Iterations 12
GAMG:  Solving for p, Initial residual = 0.0204345, Final residual = 0.000194422, No Iterations 61
GAMG:  Solving for p, Initial residual = 0.00678058, Final residual = 6.68389e-05, No Iterations 61
time step continuity errors : sum local = 5.92363e-15, global = 4.22576e-16, cumulative = 4.22576e-16
GAMG:  Solving for p, Initial residual = 0.00239474, Final residual = 2.34477e-05, No Iterations 79
GAMG:  Solving for p, Initial residual = 0.00106585, Final residual = 1.0611e-05, No Iterations 89
GAMG:  Solving for p, Initial residual = 0.000464535, Final residual = 4.64077e-06, No Iterations 155
time step continuity errors : sum local = 4.1481e-16, global = -8.04959e-19, cumulative = 4.21771e-16
GAMG:  Solving for p, Initial residual = 0.000224096, Final residual = 2.31606e-06, No Iterations 300
GAMG:  Solving for p, Initial residual = 0.000105327, Final residual = 1.4517e-06, No Iterations 300
DICPCG:  Solving for p, Initial residual = 5.24223e-05, Final residual = 9.96327e-07, No Iterations 136
time step continuity errors : sum local = 8.91004e-17, global = 3.39321e-18, cumulative = 4.25164e-16
DILUPBiCGStab:  Solving for omega, Initial residual = 1.42567e-15, Final residual = 3.97108e-30, No Iterations 3
DILUPBiCGStab:  Solving for k, Initial residual = 1.12692e-11, Final residual = 1.63946e-27, No Iterations 3
bounding k, min: -1.75187e-10 max: 946.84 average: 2.30206
DILUPBiCGStab:  Solving for ReThetat, Initial residual = 2.3811e-09, Final residual = 5.1669e-28, No Iterations 3
DILUPBiCGStab:  Solving for gammaInt, Initial residual = 3.48693e-10, Final residual = 4.30537e-31, No Iterations 3
PIMPLE: iteration 2
DILUPBiCGStab:  Solving for Urelx, Initial residual = 4.25948e-06, Final residual = 1.35464e-31, No Iterations 4
DILUPBiCGStab:  Solving for Urely, Initial residual = 3.87176e-05, Final residual = 7.55888e-30, No Iterations 4
DILUPBiCGStab:  Solving for Urelz, Initial residual = 4.06583e-06, Final residual = 1.66793e-31, No Iterations 4
GAMG:  Solving for p, Initial residual = 0.224347, Final residual = 0.00203955, No Iterations 7
GAMG:  Solving for p, Initial residual = 0.0155198, Final residual = 0.000149521, No Iterations 75
GAMG:  Solving for p, Initial residual = 0.00587188, Final residual = 5.64349e-05, No Iterations 53
time step continuity errors : sum local = 3.79089e-15, global = -2.83492e-16, cumulative = 1.41672e-16
GAMG:  Solving for p, Initial residual = 0.0024005, Final residual = 2.334e-05, No Iterations 65
GAMG:  Solving for p, Initial residual = 0.0010719, Final residual = 1.04598e-05, No Iterations 67
GAMG:  Solving for p, Initial residual = 0.000496189, Final residual = 4.94625e-06, No Iterations 89
time step continuity errors : sum local = 3.30134e-16, global = -1.57436e-17, cumulative = 1.25929e-16
GAMG:  Solving for p, Initial residual = 0.000235522, Final residual = 2.34465e-06, No Iterations 150
GAMG:  Solving for p, Initial residual = 0.000113833, Final residual = 1.1541e-06, No Iterations 300
DICPCG:  Solving for p, Initial residual = 5.60628e-05, Final residual = 9.92177e-07, No Iterations 118
time step continuity errors : sum local = 6.62022e-17, global = -2.44787e-18, cumulative = 1.23481e-16
DILUPBiCGStab:  Solving for omega, Initial residual = 3.96401e-16, Final residual = 9.82392e-31, No Iterations 3
DILUPBiCGStab:  Solving for k, Initial residual = 9.78711e-12, Final residual = 9.84719e-28, No Iterations 3
bounding k, min: 0 max: 946.689 average: 2.30207
DILUPBiCGStab:  Solving for ReThetat, Initial residual = 5.55254e-10, Final residual = 2.83376e-28, No Iterations 3
DILUPBiCGStab:  Solving for gammaInt, Initial residual = 6.20827e-11, Final residual = 9.70914e-31, No Iterations 3
PIMPLE: converged in 2 iterations
ExecutionTime = 374.59 s  ClockTime = 375 s

forces forces write:
    Sum of forces
        Total    : (1.61885e+07 -2.42372e+07 7.42024e+06)
        Pressure : (1.61885e+07 -2.42372e+07 7.4202e+06)
        Viscous  : (-49.2526 49.8269 37.1996)
    Sum of moments
        Total    : (-2.93299e+07 3.23877e+08 3.04495e+06)
        Pressure : (-2.93289e+07 3.23878e+08 3.04493e+06)
        Viscous  : (-983.493 -1277.54 19.7219)


volFieldValue minmaxdomain_scalar write:

volFieldValue mindomain_scalar write:
    min(region0) of p = -2.11475e+08

volFieldValue maxdomain_scalar write:
    max(region0) of p = 2.36003e+08

Miscellaneous:
- SRFProperties:

SRFModel        rpm;

origin          (0 0 0);
axis            (0 1 0);

rpmCoeffs
{
    rpm        15; 
}

- boundary

7
(
    BLADE
    {
        type            wall;
        inGroups        1(wall);
        nFaces          84769;
        startFace       46191188;
    }
    INLET
    {
        type            patch;
        inGroups        1(patch);
        nFaces          59648;
        startFace       46275957;
    }
    HUB
    {
        type            patch;
        inGroups        1(patch);
        nFaces          59693;
        startFace       46335605;
    }
    OUTLET
    {
        type            patch;
        inGroups        1(patch);
        nFaces          59648;
        startFace       46395298;
    }
    SIDE_LEFT
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          59136;
        startFace       46454946;
        matchTolerance  0.0001;
        transform       rotational;
        neighbourPatch  SIDE_RIGHT;
        rotationAxis    (0 1 0);
        rotationCentre  (0 0 0);
    }
    SIDE_RIGHT
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          55552;
        startFace       46514082;
        matchTolerance  0.0001;
        transform       rotational;
        neighbourPatch  SIDE_LEFT;
        rotationAxis    (0 1 0);
        rotationCentre  (0 0 0);
    }
    TOP
    {
        type            patch;
        inGroups        1(patch);
        nFaces          62904;
        startFace       46569634;
    }
)

- BC:
Urel:
inlet - SRFVelocity,
top - SRFFreestreamVelocity,
outlet - pressureInletOutletVelocity
blade - noSlip

p:
outlet - fixedValue
zeroGradient everywhere else

Thanks in advance, let me know if more information is needed
Christoph

Figures: