Horus 
February 26, 2013 10:31 
Trouble with simple AMI case
Hello,
I have a case of a simple geometry on which I want to use AMI interpolation for rotation.
I construct it from two meshes. The first one is a large box and cylinder. The second one the same cylinder but mesh generation startpoint inside the cylinder and a simple nonaxisymmetric wheel which is completely inside the cylinder. The box has slip condition at the walls and zeroGradient/fixedValue in/outflow. The meshes are generated using Numeca Spider and converted to OF using fluent3DMeshToFoam.
Turbulence is disabled.
The two meshes are merged using mergeMeshes. To construct a zone from the inside region I use topoSet:
Code:
actions
(
{
name tempBox;
type cellSet;
action new;
source boxToCell;
sourceInfo {box (100 100 100 ) (100 100 100); }
}
{
name rotZone;
type cellSet;
action new;
source regionToCell;
sourceInfo { set tempBox; insidePoint (0.03 0.02 0.05); } // A point inside the rotating mesh
}
{
name rotZone;
type cellZoneSet;
action new;
source setToCellZone;
sourceInfo { set rotZone; }
}
{
name tempBox;
type cellSet;
action remove;
}
A changeDictionary call modifies the AMI patches in the boundary dict.
I've taken my system dictory from the propeller tutorial cases, my solver is pimpleDyMFoam as well. Initial timestep is 1e5 and maxCo 1. fvSchemes and fvSolvers are unmodified except pRefCell / pRefValue.
I'm not sure if AMI needs a overlap or gap between the two meshes. I've tried three methods: unchanged sized and the inside scaled to 99,9% and 100,1% resulting in a visible gap/overlap using transformPoints scale. All cases crash with similiar behavior.
The case was decomposed using scotch for 128 processors.
The case starts just fine, but after a few timesteps Co rises / timestep shrinks until it crashes.
A timestep looks like that for example:
Code:
Courant Number mean: 1.4220815e09 max: 1.986819
deltaT = 4.552641e13
Time = 1.09198398e05
solidBodyMotionFunctions::rotatingMotion::transformation(): Time = 1.091984e05 transformation: ((0 0 0) (0.99999846 (0 0.0017549257 0)))
AMI: Creating addressing and weights between 75608 source faces and 128434 target faces
AMI: Patch source weights min/max/average = 0.91541718, 1.0695428, 0.99960354
AMI: Patch target weights min/max/average = 0.98438672, 1.1577481, 1.0012444
PIMPLE: iteration 1
smoothSolver: Solving for Ux, Initial residual = 8.2800706e05, Final residual = 3.2848892e06, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 5.247264e05, Final residual = 2.5868548e06, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 7.837248e05, Final residual = 3.5215317e06, No Iterations 1
GAMG: Solving for p, Initial residual = 0.2816471, Final residual = 0.0027095654, No Iterations 4
time step continuity errors : sum local = 3.7889088e11, global = 1.9208336e13, cumulative = 4.9011936e10
PIMPLE: iteration 2
smoothSolver: Solving for Ux, Initial residual = 9.2696402e06, Final residual = 7.1946491e07, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 6.6339078e06, Final residual = 5.1357597e07, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 1.0457223e05, Final residual = 7.8017092e07, No Iterations 2
GAMG: Solving for p, Initial residual = 0.23159011, Final residual = 0.0020297622, No Iterations 4
time step continuity errors : sum local = 3.7371482e11, global = 1.304155e13, cumulative = 4.9024978e10
PIMPLE: iteration 3
DILUPBiCG: Solving for Ux, Initial residual = 3.4757571e05, Final residual = 1.0572902e07, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 2.0913946e05, Final residual = 5.5933975e07, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 4.4476877e05, Final residual = 3.8734961e07, No Iterations 3
GAMG: Solving for p, Initial residual = 0.30341415, Final residual = 8.5899541e07, No Iterations 16
time step continuity errors : sum local = 1.5030424e14, global = 3.4608435e16, cumulative = 4.9025012e10
ExecutionTime = 104.46 s ClockTime = 105 s
I've uploaded the complete case to http://xgm.de/upload/OF/ (archive and webbrowsable). The case I have uploaded uses a 99,9% scaled inner mesh. I can of course provide the other ones, too. Not all timesteps are included but the first three ones..
I would really appreciate if someone would have a look and an idea why these cases all diverge.
Thanks!
Florian
