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November 2, 2024, 17:35 |
AMI weight goes to 0 at every timestep
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Hello everyone,
I'm simulating a stacked propeller using cyclicAMI bc in OpenFoam 9. I have successfully completed a simulation with a coarser mesh, however, I have problems with the simulation after refinement. I have noticed that the AMI weight goes to 0 at every timestep. I used blockMesh for the domain and then applied shM to AMI and fans. To create AMI I used createBaffles utility. I had this problem before and was able to overcome this by adjusting snappyHexMesh settings (however I am not exactly sure what helped), but not at every time step. The only thing I changed is increased the refinementSurfaces level for fan1 and fan2 from (3 4) to (4 5). Here is my sHM dict: Code:
/*--------------------------------*- C++ -*----------------------------------*\ ========= | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox \\ / O peration | Website: https://openfoam.org \\ / A nd | Version: 9 \\/ M anipulation | \*---------------------------------------------------------------------------*/ FoamFile { format ascii; class dictionary; object snappyHexMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // castellatedMesh true; snap true; addLayers true; geometry { AMI.stl { type triSurfaceMesh; name AMI; } fan1.stl { type triSurfaceMesh; name fan1; } fan2.stl { type triSurfaceMesh; name fan2; } refinementBox { type searchableBox; min (1.8 -0.5 -0.5); max (3 0.5 0.5); } }; castellatedMeshControls { maxLocalCells 100000; maxGlobalCells 7000000; minRefinementCells 0; maxLoadUnbalance 0.10; nCellsBetweenLevels 3; features ( { file "fan1.eMesh"; level 4; } { file "fan2.eMesh"; level 4; } { file "AMI.eMesh"; level 4; } ); refinementSurfaces { AMI { level (3 3); cellZone rotating_zone; faceZone rotating_zone; cellZoneInside inside; } fan1 { level (4 5); } fan2 { level (4 5); } } resolveFeatureAngle 30; refinementRegions { AMI { mode inside; level 2; } refinementBox { mode inside; level 1; } } locationInMesh (0.61 0 0); allowFreeStandingZoneFaces true; } snapControls { nSmoothPatch 3; tolerance 4.0; nSolveIter 50; nRelaxIter 5; //nFeatureSnapIter 25; implicitFeatureSnap true; explicitFeatureSnap false; multiRegionFeatureSnap false; } // Settings for the layer addition. addLayersControls { relativeSizes true; layers { "(fan).*" { nSurfaceLayers 7; } } expansionRatio 1.0; finalLayerThickness 0.3; minThickness 0.1; nGrow 0; featureAngle 60; nRelaxIter 3; nSmoothSurfaceNormals 1; nSmoothNormals 3; nSmoothThickness 2; maxFaceThicknessRatio 0.5; maxThicknessToMedialRatio 0.3; minMedianAxisAngle 90; nBufferCellsNoExtrude 0; nLayerIter 20; } meshQualityControls { maxNonOrtho 65; maxBoundarySkewness 20; maxInternalSkewness 4; maxConcave 80; minFlatness 0.5; minVol 1e-13; minTetQuality 1e-30; minArea -1; minTwist 0.02; minDeterminant 0.001; minFaceWeight 0.02; minVolRatio 0.01; minTriangleTwist -1; // Advanced //- Number of error distribution iterations nSmoothScale 4; //- Amount to scale back displacement at error points errorReduction 0.75; } // Advanced // Merge tolerance. Is fraction of overall bounding box of initial mesh. // Note: the write tolerance needs to be higher than this. mergeTolerance 1e-6; // ************************************************************************* // and tried to follow Artur's advide. But I think it is not applicable to my case, since AMI goes to 0 at every time step. Increasing FeatureSnapIter gives skewed faces in the propeller so I disabled it. I also tried turning on implicitFeatureSnap as was suggested in the post, but it did not help. checkMesh does not give any errors. The AMI patches look identical in paraview. I attached the clip of the rotating zone. Any help would be greatly appreciated! AMI1.jpg AMI2.jpg rotating_zone.jpg |
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