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March 15, 2013, 14:49 
calculation stops after few time steps

#1 
Senior Member

Hi Guys,
I am facing strange problem for last one week, I am using MRFSimpleFoam, I am simulating axial fan. I am using GAMBIT for meshing. I am using one passage of the fan, with hybrid mesh. I have successfully simulated one case with good results. when I tried to do grid check, I changed the mesh in to 4.5 million cells. The geometry and boundary condition everything is same except mesh size, There I am facing epsilon bounding problem, and time step continuity increasing, after few time step the calculation not moving further. I tried the following steps to solve my problem, i) for epsilon bounding problem  > divSchemes > div(phi,epsilon) Gauss upwind; but no use, still epsilon is bounding. ii) time step continuity error  > fvSolution  P > reltol >0.005 no change in the simulation, iii) I checked the yPlus, it looks fine: Patch 1 named top2 y+ : min: 58.8464 max: 78.8647 average: 73.7851 Patch 2 named top1 y+ : min: 27.2827 max: 91.6556 average: 48.7005 Patch 3 named top0 y+ : min: 62.2679 max: 78.8773 average: 74.4014 Patch 4 named center1 y+ : min: 51.1635 max: 64.7924 average: 61.8537 Patch 5 named fan y+ : min: 28.5618 max: 99.464 average: 47.9173 Patch 6 named center0 y+ : min: 62.5154 max: 70.3021 average: 65.0959 iv) I tried kepsilon and kOmegaSST none of them is working, v) CheckMesh Create time Create polyMesh for time = 0 Time = 0 Mesh stats points: 1739434 faces: 8687515 internal faces: 8536569 cells: 3491346 boundary patches: 16 point zones: 0 face zones: 1 cell zones: 2 Overall number of cells of each type: hexahedra: 0 prisms: 3258700 wedges: 0 pyramids: 0 tet wedges: 0 tetrahedra: 232646 polyhedra: 0 Checking topology... Boundary definition OK. Cell to face addressing 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 outlet 4468 2324 ok (nonclosed singly connected) top2 35990 36642 ok (nonclosed singly connected) top1 2877 1535 ok (nonclosed singly connected) top0 8540 8742 ok (nonclosed singly connected) center1 14750 15366 ok (nonclosed singly connected) fan 5016 2659 ok (nonclosed singly connected) center0 3360 3525 ok (nonclosed singly connected) inlet 4447 2317 ok (nonclosed singly connected) ILR0 7000 7191 ok (nonclosed singly connected) ILR1 7000 7191 ok (nonclosed singly connected) OLR0 27140 27777 ok (nonclosed singly connected) OLR1 27140 27777 ok (nonclosed singly connected) CLR0 795 455 ok (nonclosed singly connected) CLR1 795 455 ok (nonclosed singly connected) FCLR0 814 462 ok (nonclosed singly connected) FCLR1 814 462 ok (nonclosed singly connected) Checking geometry... Overall domain bounding box (0.217015 0.543554 1.5) (0.771 0.158713 6) Mesh (nonempty, nonwedge) directions (1 1 1) Mesh (nonempty) directions (1 1 1) Boundary openness (2.48875e14 1.40014e13 7.74113e17) OK. Max cell openness = 3.24529e16 OK. Max aspect ratio = 15.6835 OK. Minumum face area = 2.13538e06. Maximum face area = 0.000141986. Face area magnitudes OK. Min volume = 2.92584e09. Max volume = 6.74344e07. Total volume = 1.47216. Cell volumes OK. Mesh nonorthogonality Max: 82.8897 average: 5.76063 *Number of severely nonorthogonal faces: 99. Nonorthogonality check OK. <<Writing 99 nonorthogonal faces to set nonOrthoFaces Face pyramids OK. Max skewness = 2.35351 OK. Coupled point location match (average 0.000113918) OK. Mesh OK. End solver output: it stoped moving at 5 th time step Starting time loop Time = 1 smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.00571946, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.00556588, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 1, Final residual = 0.00736422, No Iterations 6 GAMG: Solving for p, Initial residual = 1, Final residual = 0.0441907, No Iterations 38 GAMG: Solving for p, Initial residual = 0.012071, Final residual = 0.00021857, No Iterations 2 GAMG: Solving for p, Initial residual = 0.00250672, Final residual = 5.80544e05, No Iterations 3 time step continuity errors : sum local = 0.134507, global = 0.0245819, cumulative = 0.0245819 smoothSolver: Solving for epsilon, Initial residual = 0.103833, Final residual = 9.1326e05, No Iterations 4 bounding epsilon, min: 3.54789 max: 80.4213 average: 0.993169 smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.00974666, No Iterations 4 ExecutionTime = 60.77 s ClockTime = 61 s Time = 2 smoothSolver: Solving for Ux, Initial residual = 0.482585, Final residual = 0.00156254, No Iterations 8 smoothSolver: Solving for Uy, Initial residual = 0.513851, Final residual = 0.00198613, No Iterations 8 smoothSolver: Solving for Uz, Initial residual = 0.973847, Final residual = 0.00548264, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00722092, Final residual = 0.000359208, No Iterations 5 GAMG: Solving for p, Initial residual = 0.0103071, Final residual = 0.00025249, No Iterations 2 GAMG: Solving for p, Initial residual = 0.00168303, Final residual = 8.27458e05, No Iterations 3 time step continuity errors : sum local = 0.0521777, global = 0.00277576, cumulative = 0.0218062 smoothSolver: Solving for epsilon, Initial residual = 0.162637, Final residual = 0.000535318, No Iterations 4 bounding epsilon, min: 85.4964 max: 53189.4 average: 4.97721 smoothSolver: Solving for k, Initial residual = 0.673913, Final residual = 0.00405384, No Iterations 4 ExecutionTime = 91.03 s ClockTime = 92 s Time = 3 smoothSolver: Solving for Ux, Initial residual = 0.186656, Final residual = 0.000928521, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.230005, Final residual = 0.000341969, No Iterations 2 smoothSolver: Solving for Uz, Initial residual = 0.30883, Final residual = 0.000804547, No Iterations 6 GAMG: Solving for p, Initial residual = 0.0158289, Final residual = 0.000679748, No Iterations 24 GAMG: Solving for p, Initial residual = 0.994707, Final residual = 0.0375188, No Iterations 3 GAMG: Solving for p, Initial residual = 0.244631, Final residual = 0.0080995, No Iterations 3 time step continuity errors : sum local = 1.23811e+06, global = 55.2375, cumulative = 55.2593 smoothSolver: Solving for epsilon, Initial residual = 0.999999, Final residual = 0.00488149, No Iterations 4 smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.00568028, No Iterations 4 ExecutionTime = 131.68 s ClockTime = 133 s Time = 4 smoothSolver: Solving for Ux, Initial residual = 0.635494, Final residual = 0.00550478, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.545846, Final residual = 0.001546, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.506895, Final residual = 0.00203654, No Iterations 4 GAMG: Solving for p, Initial residual = 0.999569, Final residual = 0.0489144, No Iterations 703 GAMG: Solving for p, Initial residual = 9.25062e08, Final residual = 9.919e09, No Iterations 513 GAMG: Solving for p, Initial residual = 5.71199e05, Final residual = 2.46643e08, No Iterations 1 time step continuity errors : sum local = 7.14548e+11, global = 4.74329e+10, cumulative = 4.74329e+10 smoothSolver: Solving for epsilon, Initial residual = 0.999748, Final residual = 7.93481e05, No Iterations 4 smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.00500452, No Iterations 2 ExecutionTime = 742.01 s ClockTime = 745 s Time = 5 smoothSolver: Solving for Ux, Initial residual = 0.967222, Final residual = 0.00860478, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.961546, Final residual = 0.00797491, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.961858, Final residual = 0.00706433, No Iterations 4 I have no clue about the problem, Please help me to solve this problem, Thank you very much for your time and help, Thanks, Sivakumar 

March 15, 2013, 15:24 

#2 
Senior Member
Join Date: Nov 2009
Location: Michigan
Posts: 135
Rep Power: 9 
Its stopping while solving for p, and you have high continuity errors which usually go together.
Were you having same nonorthogonality before? Are the two meshes of comparable quality? Try underrelaxing more. What are your relaxation factors? Can you also post the schemes you are using? 

March 15, 2013, 16:56 

#3 
Senior Member

Hi Champhekar,
Thank you very much for your reply, For your first question : yes, Due to high skewness the check mesh has been failed, but the case is running as well I got good results. Create time Create polyMesh for time = 0 Time = 0 Mesh stats points: 3229772 faces: 9489336 internal faces: 9291864 cells: 3130200 boundary patches: 16 point zones: 0 face zones: 1 cell zones: 1 Overall number of cells of each type: hexahedra: 3130200 prisms: 0 wedges: 0 pyramids: 0 tet wedges: 0 tetrahedra: 0 polyhedra: 0 Checking topology... Boundary definition OK. Cell to face addressing 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 top2 29000 29559 ok (nonclosed singly connected) top1 2536 2647 ok (nonclosed singly connected) top0 10200 10419 ok (nonclosed singly connected) outlet 4350 4484 ok (nonclosed singly connected) inlet 5100 5244 ok (nonclosed singly connected) center1 29000 29559 ok (nonclosed singly connected) fan 6586 6847 ok (nonclosed singly connected) center0 10200 10419 ok (nonclosed singly connected) ILR0 11250 11476 ok (nonclosed singly connected) ILR1 11250 11476 ok (nonclosed singly connected) OLR0 37500 38076 ok (nonclosed singly connected) OLR1 37500 38076 ok (nonclosed singly connected) CLR0 750 836 ok (nonclosed singly connected) CLR1 750 836 ok (nonclosed singly connected) FCLR0 750 836 ok (nonclosed singly connected) FCLR1 750 836 ok (nonclosed singly connected) Checking geometry... Overall domain bounding box (0.0758611 0.00381591 1.5) (0.771091 0.642452 6) Mesh (nonempty, nonwedge) directions (1 1 1) Mesh (nonempty) directions (1 1 1) Boundary openness (1.07228e14 1.69542e15 7.94528e17) OK. Max cell openness = 3.54673e16 OK. Max aspect ratio = 14.6389 OK. Minumum face area = 1.53323e06. Maximum face area = 0.000256597. Face area magnitudes OK. Min volume = 9.44895e09. Max volume = 1.58035e06. Total volume = 1.47172. Cell volumes OK. Mesh nonorthogonality Max: 79.8654 average: 10.9221 *Number of severely nonorthogonal faces: 7098. Nonorthogonality check OK. <<Writing 7098 nonorthogonal faces to set nonOrthoFaces Face pyramids OK. ***Max skewness = 5.53165, 62 highly skew faces detected which may impair the quality of the results <<Writing 62 skew faces to set skewFaces Coupled point location match (average 1.89162e09) OK. Failed 1 mesh checks. End For your second question: yes, I think the new mesh is better than old one. my relaxing factors are: epsilon > 0.5 k> 0.5 U >0.7 p > 0.2 fvSchemes is: ddtSchemes { default steadyState; } gradSchemes { default Gauss linear; grad(p) Gauss linear; grad(omega) Gauss linear; grad(epsilon) Gauss linear; grad(U) Gauss linear; grad(k) Gauss linear; } divSchemes { default none; div(phi,U) Gauss linear; div(phi,k) Gauss upwind; div(phi,omega) Gauss upwind; div(phi,epsilon) Gauss upwind; div((nuEff*dev(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear corrected; } interpolationSchemes { default linear; interpolate(U) linear; } snGradSchemes { default corrected; } fluxRequired { default no; p ; } fvSolution: solvers { p { solver GAMG; tolerance 1e08; relTol 0.005; smoother GaussSeidel; nPreSweeps 0; nPostSweeps 2; cacheAgglomeration true; nCellsInCoarsestLevel 20; agglomerator faceAreaPair; mergeLevels 1; } U { solver smoothSolver; smoother GaussSeidel; nSweeps 2; tolerance 1e07; relTol 0.01; minIter 1; maxIter 1000; } k { solver smoothSolver; smoother GaussSeidel; nSweeps 2; tolerance 1e07; relTol 0.01; minIter 1; maxIter 1000; } omega { solver smoothSolver; smoother GaussSeidel; tolerance 1e7; relTol 0.01; nSweeps 1; minIter 1; maxIter 1000; } epsilon { solver smoothSolver; smoother GaussSeidel; nSweeps 2; tolerance 1e07; relTol 0.01; minIter 1; maxIter 1000; } } SIMPLE { momentumPredictor yes; nNonOrthogonalCorrectors 2; // even I tried with 5 as well pRefCell 0; pRefValue 0; convergence 1e08; residualControl { p 1e5; U 1e5; nuTilda 1e5; } } potentialFlow { nNonOrthogonalCorrectors 10; } relaxationFactors { p 0.2; U 0.7; k 0.5; epsilon 0.5; omega 0.7; } Thanks again, Sivakumar 

March 15, 2013, 17:16 

#4 
Senior Member
Join Date: Nov 2009
Location: Michigan
Posts: 135
Rep Power: 9 
Try running with lower urfs: p=0.2,u=0.4,k=0.2,epsilon=0.2 and see if the results stabilize. If this doesn't work then if possible upload your case people will take a look at it


March 15, 2013, 17:21 

#5 
Senior Member

Hi,
Sure I will try it tomorrow morning, as well I will upload the case if I didnt get success. Thanks, Sivakumar 

March 16, 2013, 06:54 

#6 
Senior Member

Hi,
I followed your suggestion, the simulation is going on. Still the epsilon is bounding periodically, Time = 118 smoothSolver: Solving for Ux, Initial residual = 0.00240776, Final residual = 4.80671e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00215672, Final residual = 3.97876e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00114005, Final residual = 2.60887e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0311113, Final residual = 2.6898e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00458921, Final residual = 4.32191e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.0011232, Final residual = 1.00024e06, No Iterations 8 time step continuity errors : sum local = 2.55467e06, global = 1.96173e07, cumulative = 0.00316148 smoothSolver: Solving for epsilon, Initial residual = 0.000881991, Final residual = 1.36034e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000414547, Final residual = 7.2776e07, No Iterations 2 ExecutionTime = 4453.44 s ClockTime = 4473 s Time = 119 smoothSolver: Solving for Ux, Initial residual = 0.00239848, Final residual = 4.78232e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00214397, Final residual = 3.95226e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00113472, Final residual = 2.59713e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0309294, Final residual = 2.49886e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00456688, Final residual = 1.74982e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00111512, Final residual = 1.08107e06, No Iterations 8 time step continuity errors : sum local = 2.77298e06, global = 1.59081e07, cumulative = 0.00316132 smoothSolver: Solving for epsilon, Initial residual = 0.00089803, Final residual = 1.3877e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000413739, Final residual = 7.26966e07, No Iterations 2 ExecutionTime = 4474.66 s ClockTime = 4494 s Time = 120 smoothSolver: Solving for Ux, Initial residual = 0.00238916, Final residual = 4.75864e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00213133, Final residual = 3.92564e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00112984, Final residual = 2.58662e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0307649, Final residual = 2.42373e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00454774, Final residual = 2.59207e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00111047, Final residual = 6.3746e07, No Iterations 9 time step continuity errors : sum local = 1.64113e06, global = 1.69212e07, cumulative = 0.00316149 smoothSolver: Solving for epsilon, Initial residual = 0.000914301, Final residual = 1.41542e06, No Iterations 2 bounding epsilon, min: 0.0724017 max: 1.72002e+06 average: 309.099 smoothSolver: Solving for k, Initial residual = 0.00041297, Final residual = 7.26414e07, No Iterations 2 ExecutionTime = 4496.58 s ClockTime = 4516 s forces output: forces(pressure, viscous)((5.42683 12.6105 46.1923) (0.114387 0.810923 0.257543)) moment(pressure, viscous)((2.31694 23.9709 8.72821) (0.0377485 0.118132 0.491173)) Time = 121 smoothSolver: Solving for Ux, Initial residual = 0.00237927, Final residual = 4.73554e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00211885, Final residual = 3.90033e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00112504, Final residual = 2.57666e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0306244, Final residual = 2.39123e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00452987, Final residual = 4.45751e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.00110691, Final residual = 9.96202e07, No Iterations 8 time step continuity errors : sum local = 2.57406e06, global = 7.09363e08, cumulative = 0.00316142 smoothSolver: Solving for epsilon, Initial residual = 0.000931199, Final residual = 1.44355e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000412199, Final residual = 7.2598e07, No Iterations 2 ExecutionTime = 4518.05 s ClockTime = 4538 s Time = 122 smoothSolver: Solving for Ux, Initial residual = 0.00236962, Final residual = 4.7119e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00210644, Final residual = 3.87452e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00112029, Final residual = 2.56647e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0304902, Final residual = 2.48185e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00451779, Final residual = 4.2044e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.00110201, Final residual = 1.09358e06, No Iterations 8 time step continuity errors : sum local = 2.83434e06, global = 3.41901e07, cumulative = 0.00316107 smoothSolver: Solving for epsilon, Initial residual = 0.000948287, Final residual = 1.47169e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000411494, Final residual = 7.25535e07, No Iterations 2 ExecutionTime = 4538.71 s ClockTime = 4558 s Time = 123 smoothSolver: Solving for Ux, Initial residual = 0.00236437, Final residual = 4.68802e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00209582, Final residual = 3.84905e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00111566, Final residual = 2.55566e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0303963, Final residual = 2.92078e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00452022, Final residual = 2.77572e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.00109964, Final residual = 5.38716e07, No Iterations 9 time step continuity errors : sum local = 1.40016e06, global = 1.38135e07, cumulative = 0.00316094 smoothSolver: Solving for epsilon, Initial residual = 0.000965462, Final residual = 1.49959e06, No Iterations 2 bounding epsilon, min: 20.9065 max: 1.95269e+06 average: 309.411 smoothSolver: Solving for k, Initial residual = 0.000410838, Final residual = 7.25081e07, No Iterations 2 ExecutionTime = 4559.97 s ClockTime = 4580 s Time = 124 smoothSolver: Solving for Ux, Initial residual = 0.00235251, Final residual = 4.66555e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00208287, Final residual = 3.82509e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00111042, Final residual = 2.54389e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0302671, Final residual = 1.14071e05, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00451747, Final residual = 2.7175e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00109837, Final residual = 8.3546e07, No Iterations 8 time step continuity errors : sum local = 2.17806e06, global = 2.73555e07, cumulative = 0.00316066 smoothSolver: Solving for epsilon, Initial residual = 0.000982573, Final residual = 1.52709e06, No Iterations 2 bounding epsilon, min: 0.056677 max: 2.03122e+06 average: 309.634 smoothSolver: Solving for k, Initial residual = 0.000410131, Final residual = 7.24574e07, No Iterations 2 ExecutionTime = 4582.15 s ClockTime = 4602 s Time = 125 smoothSolver: Solving for Ux, Initial residual = 0.00234385, Final residual = 4.64191e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00207182, Final residual = 3.80037e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00110526, Final residual = 2.53165e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0301641, Final residual = 1.2017e05, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00451392, Final residual = 2.52417e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00110063, Final residual = 1.01985e06, No Iterations 8 time step continuity errors : sum local = 2.66683e06, global = 4.25343e07, cumulative = 0.00316109 smoothSolver: Solving for epsilon, Initial residual = 0.000999888, Final residual = 1.55423e06, No Iterations 2 bounding epsilon, min: 12.2889 max: 2.11e+06 average: 309.92 smoothSolver: Solving for k, Initial residual = 0.000409478, Final residual = 7.2409e07, No Iterations 2 ExecutionTime = 4604.31 s ClockTime = 4624 s Time = 126 smoothSolver: Solving for Ux, Initial residual = 0.00237254, Final residual = 4.64063e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00209442, Final residual = 3.7683e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00110732, Final residual = 2.52517e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0300672, Final residual = 1.18966e05, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00454405, Final residual = 3.01768e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00113615, Final residual = 1.0217e06, No Iterations 8 time step continuity errors : sum local = 2.68079e06, global = 4.77359e07, cumulative = 0.00316061 smoothSolver: Solving for epsilon, Initial residual = 0.00101735, Final residual = 1.58086e06, No Iterations 2 bounding epsilon, min: 0.304008 max: 2.18899e+06 average: 310.272 smoothSolver: Solving for k, Initial residual = 0.000409422, Final residual = 7.24154e07, No Iterations 2 ExecutionTime = 4626.69 s ClockTime = 4647 s Time = 127 smoothSolver: Solving for Ux, Initial residual = 0.00232783, Final residual = 4.59634e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00205179, Final residual = 3.75462e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00109526, Final residual = 2.50748e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0301061, Final residual = 1.12072e05, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00453209, Final residual = 2.90322e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00112219, Final residual = 6.92667e07, No Iterations 8 time step continuity errors : sum local = 1.82403e06, global = 2.7025e07, cumulative = 0.00316034 smoothSolver: Solving for epsilon, Initial residual = 0.00103626, Final residual = 1.60873e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000408179, Final residual = 7.23165e07, No Iterations 2 ExecutionTime = 4648.99 s ClockTime = 4669 s Time = 128 smoothSolver: Solving for Ux, Initial residual = 0.00233405, Final residual = 4.57661e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.0020616, Final residual = 3.73717e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00109168, Final residual = 2.49664e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0302755, Final residual = 2.97982e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00459348, Final residual = 3.73943e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.00114733, Final residual = 8.23085e07, No Iterations 8 time step continuity errors : sum local = 2.17593e06, global = 3.18905e07, cumulative = 0.00316066 smoothSolver: Solving for epsilon, Initial residual = 0.00105797, Final residual = 1.64059e06, No Iterations 2 bounding epsilon, min: 569.998 max: 2.3476e+06 average: 311.181 smoothSolver: Solving for k, Initial residual = 0.000407702, Final residual = 7.22822e07, No Iterations 2 ExecutionTime = 4669.93 s ClockTime = 4690 s Time = 129 smoothSolver: Solving for Ux, Initial residual = 0.00231227, Final residual = 4.55455e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00203203, Final residual = 3.71174e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00108599, Final residual = 2.48557e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0301049, Final residual = 2.50101e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00452806, Final residual = 3.94536e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.00113453, Final residual = 8.28034e07, No Iterations 8 time step continuity errors : sum local = 2.19744e06, global = 2.68305e07, cumulative = 0.00316093 smoothSolver: Solving for epsilon, Initial residual = 0.00107901, Final residual = 1.67225e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000406932, Final residual = 7.22438e07, No Iterations 2 ExecutionTime = 4690.56 s ClockTime = 4711 s Time = 130 smoothSolver: Solving for Ux, Initial residual = 0.00230389, Final residual = 4.53324e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00202131, Final residual = 3.69045e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00108174, Final residual = 2.47573e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0300052, Final residual = 2.32653e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00451055, Final residual = 3.54447e06, No Iterations 7 GAMG: Solving for p, Initial residual = 0.00113564, Final residual = 7.23024e07, No Iterations 8 time step continuity errors : sum local = 1.92608e06, global = 2.34593e07, cumulative = 0.00316069 smoothSolver: Solving for epsilon, Initial residual = 0.00110286, Final residual = 1.70802e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000406402, Final residual = 7.22228e07, No Iterations 2 ExecutionTime = 4711.44 s ClockTime = 4732 s forces output: forces(pressure, viscous)((4.78114 12.7469 46.3158) (0.113974 0.809523 0.255371)) moment(pressure, viscous)((1.98857 24.1224 8.72209) (0.037699 0.117629 0.491441)) Time = 131 smoothSolver: Solving for Ux, Initial residual = 0.00229575, Final residual = 4.51222e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00201099, Final residual = 3.66935e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00107776, Final residual = 2.46639e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0299727, Final residual = 2.28834e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00450915, Final residual = 1.61566e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00113737, Final residual = 6.41323e07, No Iterations 8 time step continuity errors : sum local = 1.71533e06, global = 2.13773e07, cumulative = 0.00316091 smoothSolver: Solving for epsilon, Initial residual = 0.00112956, Final residual = 1.74827e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000405945, Final residual = 7.22167e07, No Iterations 2 ExecutionTime = 4733.32 s ClockTime = 4754 s Time = 132 smoothSolver: Solving for Ux, Initial residual = 0.00228789, Final residual = 4.49207e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00200059, Final residual = 3.64838e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00107406, Final residual = 2.45738e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0299324, Final residual = 2.31512e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00451329, Final residual = 1.8372e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00114086, Final residual = 4.80326e07, No Iterations 8 time step continuity errors : sum local = 1.28977e06, global = 3.32669e07, cumulative = 0.00316124 smoothSolver: Solving for epsilon, Initial residual = 0.00115991, Final residual = 1.79542e06, No Iterations 2 bounding epsilon, min: 3.43825 max: 2.95652e+06 average: 313.953 smoothSolver: Solving for k, Initial residual = 0.00040565, Final residual = 7.22344e07, No Iterations 2 ExecutionTime = 4754.86 s ClockTime = 4776 s Time = 133 smoothSolver: Solving for Ux, Initial residual = 0.00227798, Final residual = 4.47128e06, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.00199017, Final residual = 3.62777e06, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.00107029, Final residual = 2.44863e06, No Iterations 4 GAMG: Solving for p, Initial residual = 0.0298756, Final residual = 2.37801e05, No Iterations 6 GAMG: Solving for p, Initial residual = 0.00450553, Final residual = 2.04085e06, No Iterations 8 GAMG: Solving for p, Initial residual = 0.00113932, Final residual = 5.35346e07, No Iterations 8 time step continuity errors : sum local = 1.44307e06, global = 3.99711e07, cumulative = 0.00316164 smoothSolver: Solving for epsilon, Initial residual = 0.00119524, Final residual = 1.85147e06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 0.000405338, Final residual = 7.22478e07, No Iterations 2 ExecutionTime = 4776.02 s ClockTime = 4797 s the simulation is going on with out struck. I am not sure about the quality of the results. Please have a look of the above output and advise me is it fine or do I need to do any further refinement. Thanks, Sivakumar 

March 16, 2013, 07:59 

#7 
Senior Member

Hi everyone,
I tried my level best and I followed Champhekar suggestionsas well. I am not getting success, so I have uploaded the case in sendspace. please have look and give me your idea and corrections. I am totally hopeless, please help me. The like is : http://www.sendspace.com/file/3fy5fm Thanks, Sivakumar 

March 17, 2013, 07:37 

#8 
Senior Member

Hi Everyone,
I realized the problem. The problem is non orthogonality faces, I got some information regarding this, 0 to 50 full corrected scheme is applicable, 50 to 70 limited correction is required, 70 to 80 stability possible, accuracy compromised, above 80 stability very difficult to attain In my case, my mesh has 99 non orthogonal cells with the angle of Mesh nonorthogonality Max: 82.8897 average: 5.76063 We can see the difference between running mesh and problematic mesh from the previous mesh. I feel this is my problem. Thanks, Sivakumar 

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