| tomshutch |
July 30, 2018 11:30 |
MULES or GAMG error, hull in waves
4 Attachment(s)
Hi all,
I am running URANS simulations, interdymfoam solver in OF5.0, to evaluate wave impact loads on a yacht sailing both in upright conditions and with an heeling angle.
Before implementing waves, I run a simil-steadystate simulation, fixed geometry with interfoam, to develop the flow around the hull and obtain a stable solution. After that I switch to interdymfoam, release pitch, heave, roll and yaw two at a time and again run until I obtain again a stable solution.
The two cases have exactly the same set up except for the mesh, however, while the upright case runs with no problems, the heeled one gives a lot of troubles.
The domain is built with two adjacent inlets and two adjacent outlets because I saw this is the best way I can simulate oblique waves.
To model turbulence I use k-omega SST.
Since the upright case runs with no problems in waves, I believe that the problem is not in the boundary or initial conditions, but is a matter of mesh quality and linear solvers.
The simulations crash giving the following error
Code:
Courant Number mean: 0.000203452 max: 4652.73
Interface Courant Number mean: 3.34743e-05 max: 4652.73
deltaT = 8.8832e-09
Time = 145.747
PIMPLE: iteration 1
forces forces:
Not including porosity effects
Restraint heelingAngle: angle 0.418438 moment (1.17675e+06 0 0)
Restraint heading: angle 0.0017102 moment (0 0 -171020)
6-DoF rigid body motion
Centre of rotation: (-17.53 0 1.04225)
Centre of mass: (-17.53 0 1.04225)
Orientation: (0.999727 -0.00156266 -0.0232849 -0.00803394 0.913724 -0.406256 0.0219108 0.406334 0.913463)
Linear velocity: (0 0 0.935723)
Angular velocity: (-0.0433544 -0.184461 0.301831)
Execution time for mesh.update() = 0.99 s
smoothSolver: Solving for alpha.water, Initial residual = 1.83736e-09, Final residual = 3.84139e-13, No Iterations 4
Phase-1 volume fraction = 0.777394 Min(alpha.water) = -0.00342231 Max(alpha.water) = 1.00001
Applying the previous iteration compression flux
MULES: Correcting alpha.water
MULES: Correcting alpha.water
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.777394 Min(alpha.water) = -0.00307888 Max(alpha.water) = 1.00001
smoothSolver: Solving for alpha.water, Initial residual = 1.71623e-09, Final residual = 2.13096e-13, No Iterations 4
Phase-1 volume fraction = 0.777394 Min(alpha.water) = -0.000831378 Max(alpha.water) = 1.00001
Applying the previous iteration compression flux
MULES: Correcting alpha.water
MULES: Correcting alpha.water
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.777394 Min(alpha.water) = -0.00057803 Max(alpha.water) = 1.00001
GAMG: Solving for p_rgh, Initial residual = 0.720243, Final residual = 2.90107e+78, No Iterations 1000
time step continuity errors : sum local = 3.03974e+71, global = 6.9005e+67, cumulative = 6.9005e+67
[3] #0 [2] Foam::error::printStack(Foam::Ostream&)#0 Foam::error::printStack(Foam::Ostream&) at ??:?
[3] #1 Foam::sigFpe::sigHandler(int) at ??:?
[2] #1 Foam::sigFpe::sigHandler(int) at ??:?
[3] #2 ? at ??:?
[2] #2 ? in "/lib64/libpthread.so.0"
[2] #3 Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const in "/lib64/libpthread.so.0"
[3] #3 Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const at ??:?
[2] #4 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 ??:?
[3] #4 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 ??:?
[2] #5 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[3] #5 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[2] #6 Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
[3] #6 Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
[2] #7 at ??:?
[3] #7 Foam::fvMatrix<double>::solve(Foam::dictionary const&)Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
[2] #8 at ??:?
[3] #8 ?? at ??:?
[2] #9 __libc_start_main at ??:?
[3] #9 __libc_start_main in "/lib64/libc.so.6"
[3] #10 in "/lib64/libc.so.6"
[2] #10 ?? at ??:?
at ??:?
To get rid of the GAMG error I tried to switch to PCG to solve pressure and introduce nonOrthogonalCorrectors, with the only result that the simulations crash a couple of seconds later than with GAMG, but with a MULES error.
Given that, I created a completely new (better) mesh for the heeled case and rerun the fixed hull case first. Again this first step runs smoothly, however when I switch solver and release the first two degrees of freedom (pitch and heave) it stops again with a sudden MULES error, as in the attachment interDyMFoam.c, or a GAMG error as the previously posted.
at the link
https://1drv.ms/f/s!As9yywBJJOyYpQDp9ieKkZhPs2zs
I uploaded folders with the two cases (heel_waves with the GAMG error, and heel_dynamic with the refined mesh and MULES error), complete with all the dictionaries and logs, so that if someone is interested and has time it is possible to give it a look and maybe get back with suggestions. I cannot upload the .stl files due to confidentiality, but if needed I can upload pictures of the mesh.
Please let me know if I missed something in the description of the problem
Regards,
Tommaso |
