[mmkr825]

Hi Foamers,
I prepared my solver which is non-linear PDE. I am working on suspension flow (Fluid+Particles) through different geometries. When i compiled my solver then it is giving no errors, but when i run my case file by using my solver it is giving some error message.

Error message:-
Starting time loop

Time = 1nl [0 0 -1 0 0 0 0] 0.02716
DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 4.70429e-06, No Iterations 5
DILUPBiCG: Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
swak4Foam: Allocating new repository for sampledGlobalVariables
#0 Foam::error:rintStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#2 Uninterpreted:
#3 Foam:ILUPreconditioner::calcReciprocalD(Foam::Fi eld<double>&, Foam::lduMatrix const&) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#4 Foam:ILUPreconditioner:ILUPreconditioner(Foam: :lduMatrix::solver const&, Foam::dictionary const&) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#5 Foam::lduMatrix:reconditioner::addasymMatrixCons tructorToTable<Foam:ILUPreconditioner>::New(Foam ::lduMatrix::solver const&, Foam::dictionary const&) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#6 Foam::lduMatrix:reconditioner::New(Foam::lduMatr ix::solver const&, Foam::dictionary const&) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#7 Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#8 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/openfoam211/platforms/linuxGccDPOpt/lib/libfiniteVolume.so"
#9 Foam::fvMatrix<double>::solve() in "/home/malli_reddy/OpenFOAM/malli_reddy-2.1.1/platforms/linuxGccDPOpt/bin/twoFoam"
#10
in "/home/malli_reddy/OpenFOAM/malli_reddy-2.1.1/platforms/linuxGccDPOpt/bin/twoFoam"
#11 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6"
#12
in "/home/malli_reddy/OpenFOAM/malli_reddy-2.1.1/platforms/linuxGccDPOpt/bin/twoFoam"
Floating point exception

My governing equation involves non-linear equations. When i give good initial guess (i.e by running the case by using linear solver instead of non-linear solver at first for the guess) then the case is running properly and giving good results for simple channel flow.(in which for Mesh non-orthogonality Max: 0 average: 0)
When i repeat the above same procedure for non zero Mesh non-orthogonality then after two iterations the solution is diverging.

Please let me know what is the problem and what above error trying to explain.

Thanks
Regards
Mallikarjuna

[som87]

Only Ux and Uy?..You need to consider a Control Volume for OF.It appears there is some problem with the geometry specification.If you are going for solely 2D case, create a unit mesh in the z direction...

hope it helps

[kmooney]

Originally Posted by som87

Only Ux and Uy?..You need to consider a Control Volume for OF.It appears there is some problem with the geometry specification.If you are going for solely 2D case, create a unit mesh in the z direction...

hope it helps

If you're running a 2D case OF will only solve for the x and y components in the segregated solution so there's no problem there. If introducing mesh non-orthogonality is killing your stability, try increasing the number of nNonOrthogonalCorrectors in the /system/fvSolution dictionary. If you mesh is too skewed, however, you might be out of luck and want to try some different meshing strategies.

[som87]

O my......totally forgot about segregated solver situation. Thank you very much for the correction.