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October 23, 2016, 15:42 |
Floating point exception (yes...)
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New Member
Join Date: May 2014
Posts: 13
Rep Power: 12 |
Hello world !
I’ve been keeping an eye on the forum since a few days, when a problem has stopped my current analysis of a F1 car in OpenFoam… It was all running fine until I got into trouble, and it is called Floating point exception ! As much as I could read here and with my own conclusions, it is a problem in solving the simulation, some forces starts to increase to infinite and there becomes the trouble. I suppose it is a bad config of the 0 folder, however this exercises are just a mere copy of a modified motorbike tutorial, to suit my goals. Also I have run this simulation before, using this configuration with 11M and 8M elements, and it all were fine… I copy the error for you to see if it is possible to solve it (how can I?), then I write the details. Log.simplefoam: Code:
. . Time = 16 smoothSolver: Solving for Ux, Initial residual = 0.4577433, Final residual = 0.049488617, No Iterations 89 smoothSolver: Solving for Uy, Initial residual = 0.50514958, Final residual = 0.045692466, No Iterations 111 smoothSolver: Solving for Uz, Initial residual = 0.54803684, Final residual = 0.05058686, No Iterations 99 GAMG: Solving for p, Initial residual = 0.99997705, Final residual = 0.045319146, No Iterations 4 time step continuity errors : sum local = 5.724511e+22, global = -2.0239651e+19, cumulative = -2.0239691e+19 smoothSolver: Solving for omega, Initial residual = 0.0018840911, Final residual = 0.0018840911, No Iterations 0 smoothSolver: Solving for k, Initial residual = 0.12713486, Final residual = 0.010924944, No Iterations 4 ExecutionTime = 1531.99 s ClockTime = 1587 s forceCoeffs FC_all write: Cm = 4.4527335e+38 Cd = 2.2644272e+38 Cl = -3.1365293e+38 Cl(f) = 2.8844689e+38 Cl(r) = -6.0209981e+38 forceCoeffs FC_DF write: Cm = -8.6279513e+36 Cd = 1.8271275e+35 Cl = 3.0221822e+36 Cl(f) = -7.1168602e+36 Cl(r) = 1.0139042e+37 forceCoeffs FC_FW write: Cm = -3.9464373e+35 Cd = -3.8710834e+35 Cl = 8.5864521e+35 Cl(f) = 3.467888e+34 Cl(r) = 8.2396633e+35 forceCoeffs FC_RW write: Cm = -1.6720172e+34 Cd = -6.7760632e+32 Cl = 3.3563058e+33 Cl(f) = -1.5042019e+34 Cl(r) = 1.8398325e+34 forceCoeffs FC_MC write: Cm = -6.9842379e+36 Cd = 2.0477325e+36 Cl = 4.0989468e+36 Cl(f) = -4.9347645e+36 Cl(r) = 9.0337113e+36 forceCoeffs FC_FT write: Cm = 4.6200689e+38 Cd = 2.2455591e+38 Cl = -3.2199196e+38 Cl(f) = 3.0101091e+38 Cl(r) = -6.2300287e+38 forceCoeffs FC_RT write: Cm = -3.6955346e+35 Cd = 3.9559462e+34 Cl = 8.4964137e+34 Cl(f) = -3.2707139e+35 Cl(r) = 4.1203553e+35 forceCoeffs FC_FS write: Cm = -3.2520765e+35 Cd = -5.4436352e+33 Cl = 2.6467591e+35 Cl(f) = -1.9286969e+35 Cl(r) = 4.575456e+35 forceCoeffs FC_RS write: Cm = -1.1199115e+34 Cd = 2.4305181e+33 Cl = 2.7576384e+33 Cl(f) = -9.8202954e+33 Cl(r) = 1.2577934e+34 forceCoeffs FC_HM write: Cm = -3.3366807e+33 Cd = 7.6042636e+33 Cl = 3.3570304e+33 Cl(f) = -1.6581655e+33 Cl(r) = 5.0151959e+33 forceCoeffs FC_MS write: Cm = -6.9195888e+32 Cd = 8.0411046e+30 Cl = 1.4585541e+32 Cl(f) = -6.1903117e+32 Cl(r) = 7.6488659e+32 forces F_all write: sum of forces: pressure : (5.5478467e+40 4.7693711e+41 -7.6844967e+40) viscous : (-5.2084616e+23 2.7371834e+24 1.4683138e+24) porous : (0 0 0) sum of moments: pressure : (-2.2639604e+41 1.0909197e+41 5.2415948e+41) viscous : (6.0845954e+23 -1.8867381e+24 3.7820324e+24) porous : (0 0 0) forces F_DF write: sum of forces: pressure : (4.4764624e+37 1.5554199e+38 7.4043465e+38) viscous : (3.0718397e+20 -4.8158765e+19 2.6805852e+19) porous : (0 0 0) sum of moments: pressure : (1.2705452e+39 -2.1138481e+39 2.8288225e+38) viscous : (5.0873584e+19 -4.173384e+19 -6.2600578e+20) porous : (0 0 0) forces F_FW write: sum of forces: pressure : (-9.4841542e+37 -1.4490273e+38 2.1036808e+38) viscous : (-8.509648e+21 -8.5489268e+20 2.6137722e+21) porous : (0 0 0) sum of moments: pressure : (3.3877115e+38 -9.6687713e+37 5.6202687e+37) viscous : (3.9632255e+21 -2.5455955e+21 1.4065171e+22) porous : (0 0 0) forces F_MC write: sum of forces: pressure : (5.0169446e+38 1.5739133e+39 1.004242e+39) viscous : (-8.6441911e+21 5.3699526e+20 9.6584024e+21) porous : (0 0 0) sum of moments: pressure : (1.2975152e+39 -1.7111383e+39 1.8464863e+39) viscous : (1.6914593e+22 -1.0897105e+22 1.7843728e+22) porous : (0 0 0) forces F_RW write: sum of forces: pressure : (-1.6601355e+35 -1.1157278e+36 8.2229493e+35) viscous : (2.5444248e+18 -2.4638871e+17 4.2237586e+18) porous : (0 0 0) sum of moments: pressure : (2.2067933e+36 -4.0964422e+36 -5.083615e+36) viscous : (6.9600611e+18 -1.8908935e+19 -5.3236883e+18) porous : (0 0 0) Time = 17 smoothSolver: Solving for Ux, Initial residual = 0.65619427, Final residual = 7.0498179, No Iterations 1000 smoothSolver: Solving for Uy, Initial residual = 0.69676997, Final residual = 5.9391165, No Iterations 1000 smoothSolver: Solving for Uz, Initial residual = 0.69566693, Final residual = 7.7600318, No Iterations 1000 [5] #0 Foam::error::printStack(Foam::Ostream&) at ??:? [5] #1 Foam::sigFpe::sigHandler(int) at ??:? [5] #2 ? in "/lib/x86_64-linux-gnu/libc.so.6" [5] #3 Foam::GaussSeidelSmoother::smooth(Foam::word const&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::Field<double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, unsigned char, int) at ??:? [5] #4 Foam::GaussSeidelSmoother::smooth(Foam::Field<double>&, Foam::Field<double> const&, unsigned char, int) const at ??:? [5] #5 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMatrix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:? [5] #6 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:? [5] #7 Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:? [5] #8 Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:? [5] #9 Foam::fvMatrix<double>::solve() at ??:? [5] #10 ? at ??:? [5] #11 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" [5] #12 ? at ??:? [ubuntu:04458] *** Process received signal *** [ubuntu:04458] Signal: Floating point exception (8) [ubuntu:04458] Signal code: (-6) [ubuntu:04458] Failing at address: 0x3e80000116a [ubuntu:04458] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x354a0)[0x7f1a8f6094a0] [ubuntu:04458] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x38)[0x7f1a8f609418] [ubuntu:04458] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x354a0)[0x7f1a8f6094a0] [ubuntu:04458] [ 3] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam19GaussSeidelSmoother6smoothERKNS_4wordERNS_5FieldIdEERKNS_9lduMatrixERKS5_RKNS_10FieldFieldIS4_dEERKNS_8UPtrListIKNS_17lduInterfaceFieldEEEhi+0x42d)[0x7f1a9085788d] [ubuntu:04458] [ 4] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam19GaussSeidelSmoother6smoothERNS_5FieldIdEERKS2_hi+0x28)[0x7f1a90857c98] [ubuntu:04458] [ 5] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver6VcycleERKNS_7PtrListINS_9lduMatrix8smootherEEERNS_5FieldIdEERKS8_S9_S9_S9_S9_S9_RNS1_IS8_EESD_h+0x93d)[0x7f1a9087552d] [ubuntu:04458] [ 6] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5solveERNS_5FieldIdEERKS2_h+0x86d)[0x7f1a90877cfd] [ubuntu:04458] [ 7] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x15b)[0x7f1a929d395b] [ubuntu:04458] [ 8] simpleFoam(_ZN4Foam8fvMatrixIdE5solveERKNS_10dictionaryE+0x191)[0x468e51] [ubuntu:04458] [ 9] simpleFoam(_ZN4Foam8fvMatrixIdE5solveEv+0xd4)[0x4690a4] [ubuntu:04458] [10] simpleFoam[0x422d25] [ubuntu:04458] [11] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f1a8f5f4830] [ubuntu:04458] [12] simpleFoam[0x4248e9] [ubuntu:04458] *** End of error message *** -------------------------------------------------------------------------- mpirun noticed that process rank 5 with PID 4458 on node ubuntu exited on signal 8 (Floating point exception). #END OF LOG.SIMPLEFOAM Simulate half a F1 car using kOmegaSST turbulence model, at 20m/s. Boundary conditions: -DF: Diffuser, a wall -FW: Front wing, a wall -RW: Rear wing, a wall -MC: Monocoque, a wall -HM: Helmet, a wall -MS: Monkeyseat, a wall -FS: Front suspension, a wall -RS: Rear suspension, a wall -FT: Front tire, rotating wall -RT: Rear tire, rotating wall blockMeshDict: -Sym1: symmetric plane -movwall: tarmarc, moving at constant velocity, 20m/s -slipwall and slipwallFR: upper and front patches, slip walls. -inlet and outlet Mesh seems not to have any problem, except for some skew faces. I attached my case files, the original one that worked perfectly, and the case A_1 and A_2. In case A_1 the mesh is a little bit more refined and the FW .stl file has changed (result: 11M elements). In the A_2 the mesh is even more refined, but the problem is the same (15M elements). If more information is needed, please tell me. I beg your pardon, I know this is a common issue, but I don't have a real clue on how to solve it, or why the case A works properly and the other 2 don't ... I've also added some screenshots for you to see the geometry and some post process. |
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exception, floating, point, solve |
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