[vivien]

Hi , All,
I am using icoFoam to solve a transient case with adaptive timestep. but seems it is always diverging....

The output for checkMesh is :
Create time
Create polyMesh for time = constant

Time = constant

Mesh stats
points: 58223
faces: 569730
internal faces: 524818
cells: 273637
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Number of cells of each type:
hexahedra: 0
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 273637
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology
walls 44449 22270 ok (non-closed singly connected)
inlet 207 126 ok (non-closed singly connected)
outlet 256 153 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (-0.061288 0.00849 1.64988) (-0.01046 0.039277 1.677247)
Mesh (non-empty) directions (1 1 1)
Mesh (non-empty, non-wedge) dimensions 3
Boundary openness (8.5899149e-17 6.6577541e-17 -1.6051091e-17) OK.
Max cell openness = 3.5901936e-16 OK.
Max aspect ratio = 29.093413 OK.
Minumum face area = 7.0710678e-13. Maximum face area = 1.176651e-06. Face area magnitudes OK.
Min volume = 6.6666667e-19. Max volume = 3.9984783e-10. Total volume = 2.1648984e-06. Cell volumes OK.
Mesh non-orthogonality Max: 89.527898 average: 23.326682
*Number of severely non-orthogonal faces: 16.
Non-orthogonality check OK.
<<Writing 16 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 1.9665743 OK.

Mesh OK.

I guess the mesh looks ok? Please correct me if I am wrong.

fvSolution:
solvers
{
p GAMG
{
tolerance 1e-07;
relTol 0.02;
nCellsInCoarsestLevel 100;
mergeLevels 1;
agglomerator faceAreaPair;
cacheAgglomeration true;
smoother GaussSeidel;

};
U PBiCG
{
preconditioner DILU;
tolerance 1e-08;
relTol 0;
};
T BICCG 1e-06 0;
}

PISO
{
momentumPredictor yes;
nCorrectors 1;
nNonOrthogonalCorrectors 1;
pRefCell 0;
pRefValue 0;
}

fvScheme:
ddtSchemes
{
default Euler;
}

gradSchemes
{
default Gauss linear;
grad(p) Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss upwind;
div(phi,T) Gauss Gamma01 1;
}

laplacianSchemes
{
default none;
laplacian(nu,U) Gauss linear limited 0.7;
laplacian((1|A(U)),p) Gauss linear limited 1.0;
laplacian(DT,T) Gauss linear limited 1.0;

}

interpolationSchemes
{
default linear;
interpolate(HbyA) linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p;
T;
}



I played around with non- orthogonal correctors and tolorence for U and P, but still could not get it converged, here are the output, it is diverging very fast!
Reading transportProperties

Reading diffusivity D

Reading field T

Reading field p

Reading field U

Reading/calculating face flux field phi

Courant Number mean: 0 max: 0.0023831282

Starting time loop

Time = 8.3333333e-05

Courant Number mean: 0 max: 0.09929701
deltaT = 8.3333333e-05
DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 5.2574634e-12, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 5.2574634e-12, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 1, Final residual = 5.2574634e-12, No Iterations 3
GAMG: Solving for p, Initial residual = 1, Final residual = 0.00068299363, No Iterations 18
GAMG: Solving for p, Initial residual = 0.35193406, Final residual = 0.00029174767, No Iterations 5
GAMG: Solving for p, Initial residual = 0.05190747, Final residual = 3.4266554e-05, No Iterations 6
time step continuity errors : sum local = 2.2330719e-06, global = 1.2637473e-07, cumulative = 1.2637473e-07
GAMG: Solving for p, Initial residual = 0.016763419, Final residual = 9.269677e-06, No Iterations 8
GAMG: Solving for p, Initial residual = 0.019466652, Final residual = 9.6301569e-06, No Iterations 6
GAMG: Solving for p, Initial residual = 0.0043682596, Final residual = 3.1389903e-06, No Iterations 6
time step continuity errors : sum local = 1.9595199e-07, global = -5.4824251e-09, cumulative = 1.208923e-07
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 16.69 s ClockTime = 17 s

Time = 0.00016666667

Courant Number mean: 0.026431215 max: 5.6950248
deltaT = 1.4619883e-06
DILUPBiCG: Solving for Ux, Initial residual = 0.010169927, Final residual = 5.7842898e-09, No Iterations 4
DILUPBiCG: Solving for Uy, Initial residual = 0.0087326694, Final residual = 4.9532294e-09, No Iterations 4
DILUPBiCG: Solving for Uz, Initial residual = 0.0087461466, Final residual = 3.2302903e-09, No Iterations 4
GAMG: Solving for p, Initial residual = 0.7834439, Final residual = 0.00043958727, No Iterations 7
GAMG: Solving for p, Initial residual = 0.14170316, Final residual = 0.0001235482, No Iterations 5
GAMG: Solving for p, Initial residual = 0.029676926, Final residual = 1.7078767e-05, No Iterations 6
time step continuity errors : sum local = 2.2841843e-09, global = -9.8812202e-11, cumulative = 1.2079349e-07
GAMG: Solving for p, Initial residual = 0.0078300128, Final residual = 7.3449237e-06, No Iterations 6
GAMG: Solving for p, Initial residual = 0.0026426381, Final residual = 1.3572207e-06, No Iterations 8
GAMG: Solving for p, Initial residual = 0.0012102624, Final residual = 6.65349e-07, No Iterations 10
time step continuity errors : sum local = 8.9647023e-11, global = -2.0607007e-13, cumulative = 1.2079329e-07
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 17.84 s ClockTime = 18 s

Time = 0.00016812865

Courant Number mean: 0.00046569806 max: 31.843067
deltaT = 4.5912055e-09
DILUPBiCG: Solving for Ux, Initial residual = 8.3678721e-05, Final residual = 4.9606037e-10, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 9.7267621e-05, Final residual = 5.7888005e-10, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 8.3333045e-05, Final residual = 4.9599533e-10, No Iterations 2
GAMG: Solving for p, Initial residual = 0.98419762, Final residual = 0.00076248752, No Iterations 7
GAMG: Solving for p, Initial residual = 0.097108732, Final residual = 5.3515756e-05, No Iterations 9
GAMG: Solving for p, Initial residual = 0.045454378, Final residual = 4.2709737e-05, No Iterations 9
time step continuity errors : sum local = 6.9612888e-12, global = 2.0225585e-13, cumulative = 1.2079349e-07
GAMG: SolvReading transportProperties

Reading diffusivity D

Reading field T

Reading field p

Reading field U

Reading/calculating face flux field phi

Courant Number mean: 0 max: 0.023831282

Starting time loop

Time = 0.0005

Courant Number mean: 0 max: 0.59578206
deltaT = 0.0005
DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 7.0409203e-08, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 7.0409203e-08, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 1, Final residual = 7.0409203e-08, No Iterations 3
GAMG: Solving for p, Initial residual = 1, Final residual = 0.016798127, No Iterations 12
GAMG: Solving for p, Initial residual = 0.3558975, Final residual = 0.0034731838, No Iterations 2
time step continuity errors : sum local = 0.00099705134, global = 1.1714191e-05, cumulative = 1.1714191e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 15.95 s ClockTime = 16 s

Time = 0.001

Courant Number mean: 0.13996968 max: 4.4384077
deltaT = 8.3333333e-05
DILUPBiCG: Solving for Ux, Initial residual = 0.11464729, Final residual = 2.9174135e-08, No Iterations 24
DILUPBiCG: Solving for Uy, Initial residual = 0.091467644, Final residual = 4.479088e-08, No Iterations 23
DILUPBiCG: Solving for Uz, Initial residual = 0.095988861, Final residual = 6.6348827e-08, No Iterations 25
GAMG: Solving for p, Initial residual = 0.23196136, Final residual = 0.0040878415, No Iterations 4
GAMG: Solving for p, Initial residual = 0.39860927, Final residual = 0.004201777, No Iterations 2
time step continuity errors : sum local = 4.8978515e-05, global = -1.73328e-07, cumulative = 1.1540863e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 16.91 s ClockTime = 18 s

Time = 0.0010833333

Courant Number mean: 0.024190349 max: 21.717715
deltaT = 2.8735632e-06
DILUPBiCG: Solving for Ux, Initial residual = 0.0020506321, Final residual = 4.0884971e-08, No Iterations 6
DILUPBiCG: Solving for Uy, Initial residual = 0.0021898831, Final residual = 5.493324e-08, No Iterations 6
DILUPBiCG: Solving for Uz, Initial residual = 0.0020212488, Final residual = 4.5183454e-08, No Iterations 6
GAMG: Solving for p, Initial residual = 0.7138083, Final residual = 0.013988194, No Iterations 2
GAMG: Solving for p, Initial residual = 0.093801834, Final residual = 0.0012985737, No Iterations 3
time step continuity errors : sum local = 8.6341056e-08, global = -3.845083e-10, cumulative = 1.1540479e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 17.36 s ClockTime = 18 s

Time = 0.0010862069

Courant Number mean: 0.00083432947 max: 0.80627652
deltaT = 2.6719097e-06
DILUPBiCG: Solving for Ux, Initial residual = 0.0061496859, Final residual = 5.8374136e-08, No Iterations 6
DILUPBiCG: Solving for Uy, Initial residual = 0.0068784438, Final residual = 5.6670522e-08, No Iterations 6
DILUPBiCG: Solving for Uz, Initial residual = 0.0056791343, Final residual = 2.8457772e-08, No Iterations 7
GAMG: Solving for p, Initial residual = 0.16379347, Final residual = 0.0031669144, No Iterations 3
GAMG: Solving for p, Initial residual = 0.074312719, Final residual = 0.0013461219, No Iterations 2
time step continuity errors : sum local = 6.3156776e-08, global = 3.4768173e-10, cumulative = 1.1540826e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 17.81 s ClockTime = 19 s

Time = 0.0010888788

Courant Number mean: 0.00077633177 max: 4.7841002
deltaT = 4.1871378e-07
DILUPBiCG: Solving for Ux, Initial residual = 0.00067448997, Final residual = 8.9768133e-08, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 0.00077615173, Final residual = 7.4646456e-08, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 0.00062361969, Final residual = 5.915091e-08, No Iterations 4
GAMG: Solving for p, Initial residual = 0.6664099, Final residual = 0.0073268667, No Iterations 2
GAMG: Solving for p, Initial residual = 0.055775634, Final residual = 0.00062984175, No Iterations 4
time step continuity errors : sum local = 3.652865e-09, global = 2.0506841e-11, cumulative = 1.1540847e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 18.22 s ClockTime = 19 s

Time = 0.0010892975

Courant Number mean: 0.00012165598 max: 3.6699516
deltaT = 8.5568212e-08
DILUPBiCG: Solving for Ux, Initial residual = 0.00060625452, Final residual = 1.5691355e-08, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 0.00072688963, Final residual = 2.7718382e-08, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 0.00060667087, Final residual = 3.3252606e-08, No Iterations 2
GAMG: Solving for p, Initial residual = 0.60258306, Final residual = 0.0065788389, No Iterations 2
GAMG: Solving for p, Initial residual = 0.05267683, Final residual = 0.00063607511, No Iterations 5
time step continuity errors : sum local = 6.4386944e-10, global = 8.6304411e-13, cumulative = 1.1540848e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 18.63 s ClockTime = 19 s

Time = 0.0010893831

Courant Number mean: 2.4886952e-05 max: 4.1800856
deltaT = 1.5352737e-08
DILUPBiCG: Solving for Ux, Initial residual = 0.00044817914, Final residual = 1.6045048e-08, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 0.00053069331, Final residual = 1.6055396e-09, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 0.00043876617, Final residual = 9.1725112e-09, No Iterations 2
GAMG: Solving for p, Initial residual = 0.6517394, Final residual = 0.0070548597, No Iterations 2
GAMG: Solving for p, Initial residual = 0.063911781, Final residual = 0.0010589395, No Iterations 3
time step continuity errors : sum local = 1.711019e-10, global = 7.8656474e-12, cumulative = 1.1540856e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 18.99 s ClockTime = 20 s

Time = 0.0010894057

Courant Number mean: 2.2276194e-06 max: 13.265258
deltaT = 4.1201198e-10
DILUPBiCG: Solving for Ux, Initial residual = 5.6247141e-05, Final residual = 1.8267248e-10, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 3.2465342e-05, Final residual = 1.2096298e-10, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 2.409737e-05, Final residual = 1.0103442e-10, No Iterations 2
GAMG: Solving for p, Initial residual = 0.9618828, Final residual = 0.012544987, No Iterations 6
GAMG: Solving for p, Initial residual = 0.70825452, Final residual = 0.0091945215, No Iterations 3
time step continuity errors : sum local = 2.2360493e-10, global = 6.0390426e-13, cumulative = 1.1540859e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 19.82 s ClockTime = 21 s

Time = 0.0010894061

Courant Number mean: 2.4888645e-07 max: 5.3916982
deltaT = 5.7311993e-11
DILUPBiCG: Solving for Ux, Initial residual = 1.3437985e-05, Final residual = 7.5017277e-10, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 9.4281684e-06, Final residual = 6.1040989e-10, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 8.5585832e-06, Final residual = 6.3097901e-10, No Iterations 2
GAMG: Solving for p, Initial residual = 0.97955493, Final residual = 0.014601136, No Iterations 7
GAMG: Solving for p, Initial residual = 0.8630304, Final residual = 0.012469882, No Iterations 3
time step continuity errors : sum local = 5.5407694e-10, global = 7.9968896e-13, cumulative = 1.154086e-05
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 20.22 s ClockTime = 21 s

Time = 0.0010894062

Courant Number mean: 3.4013782e-07 max: 14.134256
deltaT = 3.0411217e-12
DILUPBiCG: Solving for Ux, Initial residual = 6.8869705e-06, Final residual = 5.3268368e-10, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 5.3151571e-06, Final residual = 4.5579494e-10, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 5.5695744e-06, Final residual = 2.1050411e-10, No Iterations 2
GAMG: Solving for p, Initial residual = 0.99059305, Final residual = 0.013330652, No Iterations 7
GAMG: Solving for p, Initial residual = 0.86461623, Final residual = 0.011334408, No Iterations 3
ing for p, Initial residual = 0.11258581, Final residual = 7.4286381e-05, No Iterations 10
GAMG: Solving for p, Initial residual = 0.34096992, Final residual = 0.00028746462, No Iterations 8
GAMG: Solving for p, Initial residual = 0.67780892, Final residual = 0.00060290894, No Iterations 8
time step continuity errors : sum local = 2.9536112e-10, global = -2.451718e-14, cumulative = 1.2079346e-07
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 19.08 s ClockTime = 20 s

Time = 0.00016813325

Courant Number mean: 3.3169797e-06 max: 249.0088
deltaT = 1.8437925e-12
DILUPBiCG: Solving for Ux, Initial residual = 2.6530561e-07, Final residual = 2.7907437e-10, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 2.525955e-07, Final residual = 2.7304897e-10, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 2.4243676e-07, Final residual = 2.7221558e-10, No Iterations 1
GAMG: Solving for p, Initial residual = 0.99989661, Final residual = 0.00069574805, No Iterations 12
GAMG: Solving for p, Initial residual = 0.80378517, Final residual = 0.00064631386, No Iterations 7
GAMG: Solving for p, Initial residual = 0.92064105, Final residual = 0.00077935544, No Iterations 7
time step continuity errors : sum local = 8.2120895e-12, global = 6.8618641e-16, cumulative = 1.2079346e-07
GAMG: Solving for p, Initial residual = 0.98893512, Final residual = 0.00069624566, No Iterations 8
GAMG: Solving for p, Initial residual = 0.99777421, Final residual = 0.00087381258, No Iterations 7
GAMG: Solving for p, Initial residual = 0.99737806, Final residual = 0.00084373749, No Iterations 7
time step continuity errors : sum local = 5.6338815e-10, global = -3.7542991e-14, cumulative = 1.2079343e-07
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for T, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 20.27 s ClockTime = 21 s

Time = 0.00016813325

Courant Number mean: 3.2611049e-06 max: 453.13692
[13] #0 Foam::error:rintStack(Foam::Ostream&) in "/vol/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[13] #1 Foam::sigFpe::sigFpeHandler(int) in "/vol/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[13] #2 __restore_rt at sigaction.c:0
[9] #0 Foam::error:rintStack(Foam::Ostream&) in "/vol/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[9] #1 Foam::sigFpe::sigFpeHandler(int) in "/vol/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[9] #2 __restore_rt at sigaction.c:0
[9] #3 Foam::Time::adjustDeltaT() in "/vol/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[5] #0 Foam::error:rintStack(Foam::Ostream&) in "/vol/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"

Can somebody give me help? Thank you very much!!!!

Vivien

[santos]

It could help if you provide some background on your case, eg Reynolds, mesh, etc. Why are you using only 1 corrector in the PISO algorithm?

Regards,
Jose Santos

[vivien]

Hi, Santos,

Thanks a lot for your quick reply!

The geometry is a blood vessel including a big aneurysm. reynolds number is estimated in the laminar range. I attched two screenshots of the geomrtry, could you please have look? Or can I send my case to you? This is not my first simulation with icoFoam but I have never met such a problem before....do you think it is because the 'Number of severely non-orthogonal faces' ?

Thank you very much!

Vivien

[vivien]

Hi, again,

I tried with different correctors(1-5), but it does not help so far...

Vivien

[santos]

Hi,

OK send it to me and I'll give it a try.

email: jose <dot> santos <at> dq.fct.unl.pt

Regards,
Jose Santos

[vivien]

Hi, Santos,

I have sent the case to you.

Thanks for your help!!

Vivien