- **OpenFOAM Running, Solving & CFD**
(*http://www.cfd-online.com/Forums/openfoam-solving/*)

- - **kEpsilon divergence**
(*http://www.cfd-online.com/Forums/openfoam-solving/118411-kepsilon-divergence.html*)

kEpsilon divergence3 Attachment(s)
hi dear all,
i am analyzing the turbulent flow over a multi element airfoil, i use kEpsilon as my turbulent model, i attach another setting except the polyMesh file that have large volume in the following. i want to know why this setting give me a huge "cd and cl" value and become diverge at last??? Create time Create mesh for time = 0 Reading field p Reading field U Reading/calculating face flux field phi Selecting incompressible transport model Newtonian Selecting RAS turbulence model kEpsilon kEpsilonCoeffs { Cmu 0.09; C1 1.44; C2 1.92; sigmaEps 1.3; } No field sources present SIMPLE: convergence criteria field p tolerance 1e-05 field U tolerance 1e-05 field "(k|epsilon|omega)" tolerance 1e-05 Starting time loop Time = 1 DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 0.0851627, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 0.0620606, No Iterations 1 DICPCG: Solving for p, Initial residual = 1, Final residual = 0.00996629, No Iterations 309 time step continuity errors : sum local = 0.0145551, global = -0.000587377, cumulative = -0.000587377 DILUPBiCG: Solving for epsilon, Initial residual = 0.855568, Final residual = 0.0131864, No Iterations 2 bounding epsilon, min: -70.6847 max: 12281.4 average: 95.7268 DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 0.0139852, No Iterations 2 ExecutionTime = 66.18 s ClockTime = 67 s forceCoeffs output: Cd = 12.5306 Cl = 8.61894 Cm = 10.947 Cl(f) = -6.63751 Cl(r) = 15.2565 forceCoeffs output: Cd = 4.63818 Cl = 4.46189 Cm = 7.69878 Cl(f) = -5.46783 Cl(r) = 9.92972 forceCoeffs output: Cd = 4.28411 Cl = 1.24044 Cm = 0.363232 Cl(f) = 0.256988 Cl(r) = 0.983452 Time = 2 DILUPBiCG: Solving for Ux, Initial residual = 0.371895, Final residual = 0.0219048, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.801151, Final residual = 0.0712947, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.934959, Final residual = 0.00914592, No Iterations 176 time step continuity errors : sum local = 0.0844986, global = -0.00533487, cumulative = -0.00592225 DILUPBiCG: Solving for epsilon, Initial residual = 0.193973, Final residual = 0.00950288, No Iterations 1 bounding epsilon, min: -4.58686e+06 max: 2.05433e+08 average: 5828.66 DILUPBiCG: Solving for k, Initial residual = 0.800037, Final residual = 0.0154131, No Iterations 2 ExecutionTime = 99.81 s ClockTime = 100 s forceCoeffs output: Cd = 74.3294 Cl = 39.1365 Cm = 55.1597 Cl(f) = -35.5915 Cl(r) = 74.728 forceCoeffs output: Cd = 29.1868 Cl = 26.3321 Cm = 46.7784 Cl(f) = -33.6123 Cl(r) = 59.9444 forceCoeffs output: Cd = 23.8554 Cl = 5.50834 Cm = 2.1903 Cl(f) = 0.563873 Cl(r) = 4.94447 Time = 3 Warning: empty x range [2:2], adjusting to [1.98:2.02] Warning: empty y range [-0.00592225:-0.00592225], adjusting to [-0.00598147:-0.00586303] Warning: empty y2 range [-0.00533487:-0.00533487], adjusting to [-0.00538822:-0.00528152] Warning: empty x range [2:2], adjusting to [1.98:2.02] Warning: empty x range [2:2], adjusting to [1.98:2.02] DILUPBiCG: Solving for Ux, Initial residual = 0.281258, Final residual = 0.00790785, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.309596, Final residual = 0.00740507, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.809451, Final residual = 0.00786146, No Iterations 184 time step continuity errors : sum local = 0.0808879, global = -0.00575251, cumulative = -0.0116748 DILUPBiCG: Solving for epsilon, Initial residual = 0.383734, Final residual = 0.00500752, No Iterations 1 bounding epsilon, min: -2.06429e+09 max: 3.22707e+10 average: 1.25176e+06 DILUPBiCG: Solving for k, Initial residual = 0.308511, Final residual = 0.00780312, No Iterations 1 ExecutionTime = 136.12 s ClockTime = 137 s forceCoeffs output: Cd = 47.6661 Cl = 44.0272 Cm = 47.4463 Cl(f) = -25.4327 Cl(r) = 69.4599 forceCoeffs output: Cd = 20.4276 Cl = 19.2879 Cm = 33.7033 Cl(f) = -24.0594 Cl(r) = 43.3473 forceCoeffs output: Cd = 15.106 Cl = 3.52259 Cm = 1.3308 Cl(f) = 0.430496 Cl(r) = 3.0921 Time = 4 DILUPBiCG: Solving for Ux, Initial residual = 0.631827, Final residual = 0.0532422, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.287384, Final residual = 0.0218062, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.0389731, Final residual = 0.000377626, No Iterations 15 time step continuity errors : sum local = 1.69174e+11, global = -0.008325, cumulative = -0.0199998 DILUPBiCG: Solving for epsilon, Initial residual = 1, Final residual = 0.0489876, No Iterations 2 DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 0.0243535, No Iterations 1 ExecutionTime = 148.98 s ClockTime = 150 s forceCoeffs output: Cd = 5.95263e+16 Cl = 5.74333e+18 Cm = 5.28543e+18 Cl(f) = -2.41377e+18 Cl(r) = 8.1571e+18 forceCoeffs output: Cd = 4.67148e+16 Cl = 3.5596e+18 Cm = 5.28543e+18 Cl(f) = -3.50563e+18 Cl(r) = 7.06523e+18 forceCoeffs output: Cd = -716.963 Cl = 84.7869 Cm = -81.2341 Cl(f) = 123.628 Cl(r) = -38.8407 Time = 5 DILUPBiCG: Solving for Ux, Initial residual = 0.540127, Final residual = 0.00501485, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.685895, Final residual = 0.0146612, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.00288552, Final residual = 0.00190082, No Iterations 1001 time step continuity errors : sum local = 7.55328e+12, global = -1.17074e+12, cumulative = -1.17074e+12 DILUPBiCG: Solving for epsilon, Initial residual = 0.165444, Final residual = 2.08731e-11, No Iterations 1 bounding epsilon, min: -5.08808e+31 max: 1.69734e+39 average: 1.19693e+34 DILUPBiCG: Solving for k, Initial residual = 0.824988, Final residual = 0.0704899, No Iterations 1 ExecutionTime = 296.84 s ClockTime = 300 s forceCoeffs output: Cd = 8.93277e+43 Cl = 1.76619e+44 Cm = 1.75932e+44 Cl(f) = -8.76223e+43 Cl(r) = 2.64242e+44 forceCoeffs output: Cd = 7.01023e+43 Cl = 1.09465e+44 Cm = 1.75932e+44 Cl(f) = -1.212e+44 Cl(r) = 2.30664e+44 forceCoeffs output: Cd = 3.8858e+13 Cl = 2.66218e+12 Cm = 6.69608e+12 Cl(f) = -5.365e+12 Cl(r) = 8.02717e+12 Time = 6 DILUPBiCG: Solving for Ux, Initial residual = 0.466989, Final residual = 0.0136307, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 0.286722, Final residual = 0.00802562, No Iterations 1 DICPCG: Solving for p, Initial residual = 0.0332657, Final residual = 0.000267814, No Iterations 3 time step continuity errors : sum local = 1.45411e+27, global = -2.89889e+11, cumulative = -1.46063e+12 please help me. thank you very much.:) |

All times are GMT -4. The time now is 07:50. |