# sowfa single turbine

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 July 11, 2014, 05:18 sowfa single turbine #1 New Member   ruben p. Join Date: Dec 2013 Location: Copenhagen, Denmark Posts: 7 Rep Power: 3 Hi, I am going to use SOWFA to simulate a windfarm and compare the results against real measurements. To start, I try to simulate a single wind turbine using the solver "windPlantPisoSolver", and after a few seconds, the execution stops with this error: Code: ```Courant Number mean: 2.0237e+06 max: 1.4461e+08 Time = 0.15 Time Step = 3 C_s = 0.168 u* = 15871 m/s ||^(1/2) = 15871 m/s _1/2 = (-1.7322e+05 -1.3412e+05 0) m/s Qs = 0 K*(m/s) || = 0 K*(m/s) L = 1e+30 m phi_m = 1 _1/2 = 532.83 K Thrust from Body Force = 1.1134e+10 Thrust from Act. Line = 5.5954e+10 Ratio = 0.19898 Torque from Body Force = -2.3774e+09 Torque from Act. Line = -1.1848e+10 Ratio = 0.20066 DILUPBiCG: Solving for Ux, Initial residual = 0.99957, Final residual = 4.5524e+10, No Iterations 1001 DILUPBiCG: Solving for Uy, Initial residual = 0.99775, Final residual = 12931, No Iterations 1001 DILUPBiCG: Solving for Uz, Initial residual = 0.99917, Final residual = 32041, No Iterations 1001 #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::sigFpe::sigHandler(int) at ??:? #2 Uninterpreted: #3 Foam::GAMGSolver::scalingFactor(Foam::Field&, Foam::Field const&, Foam::Field const&, Foam::Field const&) const at ??:? #4 Foam::GAMGSolver::scalingFactor(Foam::Field&, Foam::lduMatrix const&, Foam::Field&, Foam::FieldField const&, Foam::UPtrList const&, Foam::Field const&, unsigned char) const at ??:? #5 Foam::GAMGSolver::Vcycle(Foam::PtrList const&, Foam::Field&, Foam::Field const&, Foam::Field&, Foam::Field&, Foam::Field&, Foam::PtrList >&, Foam::PtrList >&, unsigned char) const at ??:? #6 Foam::GAMGSolver::solve(Foam::Field&, Foam::Field const&, unsigned char) const at ??:? #7 Foam::fvMatrix::solve(Foam::dictionary const&) at ??:? #8 at ??:? #9 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6" #10 at ??:? Floating point exception (core dumped)``` If I run the exact same case, with a way larger volume defined in blockMesh, it executes without any problem (but the results are incorrect). From now, even with the 0.15 sec of simulation I can see that the results make more sense, but I don't understand what's making the courant number explode... Any ideas?? Thanks, Ruben constant.zip system+0.zip

 November 25, 2014, 06:35 Re: SOWFA single turbine #2 New Member   Thomas Schulz Join Date: Jul 2014 Posts: 16 Rep Power: 3 Dear Ruben, I recently started to work with the solver suite provided by the NREL and I ran into several problems with the usage. Most of them I already solved and I think your problem with those solvers is based on several modifications made to OpenFOAM during the version changes. It may compile correctly but that does not mean it is working correctly. You may want to look into the source code of the pisoFoamTurbine solver included in the SOWFA suite and compare it to the original pisoFoam solver sources. You will find several changes (appart from the FAST modifications). If you take the original pisoFoam solver as a base and add the modifications according to the suggestions made by the SOWFA people you might be able to let it run correctly. I also think that a good start might be the fastDuct tutorial included in the suite instead of the windPlant tutorial. Was this helpful? Best, Thomas

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