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January 17, 2018, 04:18 
Time Step Continuity Errors simpleFoam

#1 
New Member
Join Date: May 2017
Location: Japan, Kitakyushu
Posts: 19
Rep Power: 8 
Hello,
I'm trying to simulate a flow around a 3Dwing. I want to use komegaSST (or kepsilon) turbulence model. I'm decreasing the size of the layers step by step, however when my y+ is near 45 the time step continuity error starts diverging and the simulation stops. I've tried to change my schemes, my BC or relaxation coefficients without success. I don't understand where this error come from knowing that the simulation run for a y+~100. Another simulation using the spalartAllmaras model also converges (with the same mesh and BC). Moreover my checkMesh is ok. Code:
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Create time Create mesh for time = 0 SIMPLE: convergence criteria field U tolerance 0.0001 field p tolerance 0.001 field "(kepsilonomega)" tolerance 0.001 Reading field p Reading field U Reading/calculating face flux field phi Selecting incompressible transport model Newtonian Selecting turbulence model type RAS Selecting RAS turbulence model kOmegaSST Selecting patchDistMethod meshWave kOmegaSSTCoeffs { 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; a1 0.31; b1 1; c1 10; F3 false; } No MRF models present No finite volume options present Starting time loop forces forces: Not including porosity effects forceCoeffs forces: Not including porosity effects Time = 1 smoothSolver: Solving for Ux, Initial residual = 0.99999, Final residual = 0.0764658, No Iterations 2 smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.0386756, No Iterations 3 smoothSolver: Solving for Uz, Initial residual = 0.999997, Final residual = 0.0791299, No Iterations 2 GAMG: Solving for p, Initial residual = 1, Final residual = 0.0690019, No Iterations 7 time step continuity errors : sum local = 0.028254, global = 0.00313196, cumulative = 0.00313196 smoothSolver: Solving for omega, Initial residual = 0.00535907, Final residual = 0.000196025, No Iterations 1 bounding omega, min: 25706.4 max: 3.8584e+06 average: 95308.2 smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.00489828, No Iterations 1 ExecutionTime = 100.23 s ClockTime = 100 s forceCoeffs forces write: Cm = 5.01564 Cd = 44.5862 Cl = 6.34427 Cl(f) = 1.84351 Cl(r) = 8.18777 Time = 2 smoothSolver: Solving for Ux, Initial residual = 0.0503861, Final residual = 0.00457665, No Iterations 2 smoothSolver: Solving for Uy, Initial residual = 0.056634, Final residual = 0.00502492, No Iterations 2 smoothSolver: Solving for Uz, Initial residual = 0.202114, Final residual = 0.0186672, No Iterations 2 GAMG: Solving for p, Initial residual = 0.490306, Final residual = 0.027328, No Iterations 2 time step continuity errors : sum local = 12.3113, global = 0.00624942, cumulative = 0.00938138 smoothSolver: Solving for omega, Initial residual = 0.00135869, Final residual = 1.21457e05, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.383071, Final residual = 0.00314367, No Iterations 1 ExecutionTime = 131.72 s ClockTime = 132 s forceCoeffs forces write: Cm = 2.32634 Cd = 20.2918 Cl = 2.99807 Cl(f) = 0.827308 Cl(r) = 3.82538 Time = 3 smoothSolver: Solving for Ux, Initial residual = 0.0923705, Final residual = 0.00468338, No Iterations 4 smoothSolver: Solving for Uy, Initial residual = 0.103414, Final residual = 0.00676207, No Iterations 4 smoothSolver: Solving for Uz, Initial residual = 0.203299, Final residual = 0.0108881, No Iterations 4 GAMG: Solving for p, Initial residual = 0.587766, Final residual = 0.0540848, No Iterations 4 time step continuity errors : sum local = 29.5512, global = 0.154192, cumulative = 0.144811 smoothSolver: Solving for omega, Initial residual = 0.0731651, Final residual = 0.00077162, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0828431, Final residual = 0.000851564, No Iterations 1 ExecutionTime = 169.14 s ClockTime = 169 s forceCoeffs forces write: Cm = 177.768 Cd = 1327 Cl = 292.705 Cl(f) = 31.4153 Cl(r) = 324.121 Time = 4 smoothSolver: Solving for Ux, Initial residual = 0.651467, Final residual = 0.0353532, No Iterations 1 smoothSolver: Solving for Uy, Initial residual = 0.684837, Final residual = 0.0367144, No Iterations 1 smoothSolver: Solving for Uz, Initial residual = 0.684076, Final residual = 0.0372442, No Iterations 1 GAMG: Solving for p, Initial residual = 0.00919992, Final residual = 0.000641066, No Iterations 7 time step continuity errors : sum local = 16.0459, global = 2.34303, cumulative = 2.19822 smoothSolver: Solving for omega, Initial residual = 0.076197, Final residual = 0.0013213, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0370577, Final residual = 0.000367212, No Iterations 1 ExecutionTime = 206.58 s ClockTime = 207 s forceCoeffs forces write: Cm = 374.837 Cd = 5347.9 Cl = 670.105 Cl(f) = 39.7839 Cl(r) = 709.889 Time = 5 smoothSolver: Solving for Ux, Initial residual = 0.599135, Final residual = 0.0538314, No Iterations 1 smoothSolver: Solving for Uy, Initial residual = 0.641251, Final residual = 0.05281, No Iterations 1 smoothSolver: Solving for Uz, Initial residual = 0.591677, Final residual = 0.0467585, No Iterations 1 GAMG: Solving for p, Initial residual = 0.0677127, Final residual = 0.00567401, No Iterations 13 time step continuity errors : sum local = 41.1121, global = 4.97447, cumulative = 7.17269 smoothSolver: Solving for omega, Initial residual = 0.0675145, Final residual = 0.00111715, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0337135, Final residual = 0.000382671, No Iterations 1 ExecutionTime = 253.04 s ClockTime = 253 s forceCoeffs forces write: Cm = 8352.88 Cd = 17220.7 Cl = 11998.4 Cl(f) = 2353.7 Cl(r) = 14352.1 Time = 6 smoothSolver: Solving for Ux, Initial residual = 0.689606, Final residual = 0.0548645, No Iterations 1 smoothSolver: Solving for Uy, Initial residual = 0.702136, Final residual = 0.064385, No Iterations 1 smoothSolver: Solving for Uz, Initial residual = 0.691323, Final residual = 0.0648999, No Iterations 1 GAMG: Solving for p, Initial residual = 0.0115375, Final residual = 0.00112664, No Iterations 165 time step continuity errors : sum local = 1635.2, global = 193.916, cumulative = 186.743 smoothSolver: Solving for omega, Initial residual = 0.124886, Final residual = 0.00154642, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0480225, Final residual = 0.000597913, No Iterations 1 ExecutionTime = 528.78 s ClockTime = 529 s forceCoeffs forces write: Cm = 5.34103e+06 Cd = 2.49835e+06 Cl = 1.2117e+07 Cl(f) = 717471 Cl(r) = 1.13995e+07 Time = 7 smoothSolver: Solving for Ux, Initial residual = 0.677576, Final residual = 0.025612, No Iterations 1 smoothSolver: Solving for Uy, Initial residual = 0.691005, Final residual = 0.0299412, No Iterations 1 smoothSolver: Solving for Uz, Initial residual = 0.662216, Final residual = 0.0543164, No Iterations 1 GAMG: Solving for p, Initial residual = 0.00381449, Final residual = 0.00746159, No Iterations 1000 time step continuity errors : sum local = 674286, global = 550585, cumulative = 550398 smoothSolver: Solving for omega, Initial residual = 0.0188267, Final residual = 0.000330376, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0507805, Final residual = 0.000431565, No Iterations 1 ExecutionTime = 2062.05 s ClockTime = 2064 s forceCoeffs forces write: Cm = 2.28456e+10 Cd = 7.07455e+10 Cl = 7.99311e+10 Cl(f) = 1.712e+10 Cl(r) = 6.28112e+10 Time = 8 smoothSolver: Solving for Ux, Initial residual = 0.666421, Final residual = 0.0453112, No Iterations 6 smoothSolver: Solving for Uy, Initial residual = 0.695728, Final residual = 0.0554333, No Iterations 3 smoothSolver: Solving for Uz, Initial residual = 0.653737, Final residual = 0.0285133, No Iterations 5 GAMG: Solving for p, Initial residual = 0.424611, Final residual = 0.0419241, No Iterations 236 time step continuity errors : sum local = 3.19872e+07, global = 2.92964e+07, cumulative = 2.8746e+07 smoothSolver: Solving for omega, Initial residual = 0.122421, Final residual = 0.00140935, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0480735, Final residual = 0.000354375, No Iterations 1 ExecutionTime = 2449.07 s ClockTime = 2452 s forceCoeffs forces write: Cm = 2.90902e+15 Cd = 5.00479e+15 Cl = 4.29443e+15 Cl(f) = 7.61808e+14 Cl(r) = 5.05624e+15 Time = 9 smoothSolver: Solving for Ux, Initial residual = 0.682372, Final residual = 0.0414407, No Iterations 3 smoothSolver: Solving for Uy, Initial residual = 0.685099, Final residual = 0.0431815, No Iterations 2 smoothSolver: Solving for Uz, Initial residual = 0.686867, Final residual = 0.0604966, No Iterations 2 GAMG: Solving for p, Initial residual = 0.574339, Final residual = 2.82489, No Iterations 1000 time step continuity errors : sum local = 3.73545e+13, global = 3.6676e+13, cumulative = 3.6676e+13 smoothSolver: Solving for omega, Initial residual = 0.00145352, Final residual = 1.949e05, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0410455, Final residual = 0.000270812, No Iterations 1 ExecutionTime = 3986.59 s ClockTime = 3991 s forceCoeffs forces write: Cm = 1.44699e+21 Cd = 2.31148e+21 Cl = 2.2355e+21 Cl(f) = 3.2924e+20 Cl(r) = 2.56474e+21 Time = 10 smoothSolver: Solving for Ux, Initial residual = 0.56782, Final residual = 0.0167332, No Iterations 2 smoothSolver: Solving for Uy, Initial residual = 0.61319, Final residual = 0.0588445, No Iterations 1 smoothSolver: Solving for Uz, Initial residual = 0.549356, Final residual = 0.0526533, No Iterations 1 GAMG: Solving for p, Initial residual = 0.97733, Final residual = 0.0958427, No Iterations 13 time step continuity errors : sum local = 3.74547e+12, global = 2.75918e+11, cumulative = 3.69519e+13 smoothSolver: Solving for omega, Initial residual = 0.00314259, Final residual = 5.58918e05, No Iterations 1 smoothSolver: Solving for k, Initial residual = 0.0131684, Final residual = 0.000191094, No Iterations 1 ExecutionTime = 4033.9 s ClockTime = 4038 s forceCoeffs forces write: Cm = 4.98589e+26 Cd = 8.00075e+26 Cl = 7.70819e+26 Cl(f) = 1.1318e+26 Cl(r) = 8.83999e+26 Code:
/**\  =========    \\ / F ield  OpenFOAM: The Open Source CFD Toolbox   \\ / O peration  Version: 4.1   \\ / A nd  Web: www.OpenFOAM.org   \\/ M anipulation   \**/ Build : 4.1 Exec : checkMesh Date : Jan 17 2018 Time : 18:05:41 Host : "node1" PID : 23705 Case : /home/dorian/OpenFOAM/dorian4.1/run/opti_CFD nProcs : 1 sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE). fileModificationChecking : Monitoring runtime modified files using timeStampMaster allowSystemOperations : Allowing usersupplied system call operations // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Create time Create polyMesh for time = 0 Time = 0 Mesh stats points: 6372893 faces: 16961350 internal faces: 16506757 cells: 5339871 faces per cell: 6.26759 boundary patches: 4 point zones: 0 face zones: 0 cell zones: 0 Overall number of cells of each type: hexahedra: 4201176 prisms: 52186 wedges: 0 pyramids: 0 tet wedges: 2 tetrahedra: 0 polyhedra: 1086507 Breakdown of polyhedra by number of faces: faces number of cells 4 91219 5 51893 6 79622 7 495583 8 198702 9 94900 10 1585 11 306 12 41478 15 31217 18 2 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 box 7200 7296 ok (nonclosed singly connected) inlet 560 609 ok (nonclosed singly connected) outlet 560 609 ok (nonclosed singly connected) wing 446273 537464 ok (closed singly connected) Checking geometry... Overall domain bounding box (5 2.60002 2) (10 3.00002 2) Mesh has 3 geometric (nonempty/wedge) directions (1 1 1) Mesh has 3 solution (nonempty) directions (1 1 1) Boundary openness (4.16873e16 7.5958e16 7.66195e15) OK. Max cell openness = 1.18722e15 OK. Max aspect ratio = 26.1576 OK. Minimum face area = 5.11162e08. Maximum face area = 0.040077. Face area magnitudes OK. Min volume = 3.57011e11. Max volume = 0.00801562. Total volume = 335.914. Cell volumes OK. Mesh nonorthogonality Max: 64.8844 average: 9.43194 Nonorthogonality check OK. Face pyramids OK. Max skewness = 3.01112 OK. Coupled point location match (average 0) OK. Mesh OK. End Code:
/** C++ **\  =========    \\ / F ield  OpenFOAM: The Open Source CFD Toolbox   \\ / O peration  Version: 4.1   \\ / A nd  Web: www.OpenFOAM.org   \\/ M anipulation   \**/ FoamFile { version 2.0; format ascii; class volScalarField; object k; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // kInlet 38.11; // approx k = 1.5*(I*U)^2 ; I = 0.1 dimensions [0 2 2 0 0 0 0]; internalField uniform $kInlet; boundaryField { inlet { type fixedValue; value uniform $kInlet; } outlet { type inletOutlet; inletValue uniform $kInlet; value uniform $kInlet; } wing { type kqRWallFunction; value uniform $kInlet; } box { type zeroGradient; } } // ************************************************************************* // Thank you ! 

October 9, 2022, 09:23 

#2 
New Member
Dai Li
Join Date: Jun 2022
Posts: 4
Rep Power: 3 
Hello. Do you figure out the problem? I also meet the problem. Could you tell the way that you solve this problem? Thanks a lot.


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