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MesquiteMotionSolver, prescribed motion at boundary condition depends on deltaT ? |
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June 3, 2015, 05:58 |
MesquiteMotionSolver, prescribed motion at boundary condition depends on deltaT ?
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#1 |
New Member
Al_th
Join Date: Apr 2015
Posts: 19
Rep Power: 11 |
Hi everyone,
[OF 2.3] I am encountering a weird (but maybe intentional) behaviour using mesquite as a motion solver for a dynamic mesh problem. I am simulating a cylinder where one of the base is moving in and out. At first, I was using the velocityLaplacian solver but due to some of its behaviour on cyclic patch, I had to find an alternative (basically it replaces the pointMotionU at each time steps and force cyclic patch to be cyclic even if I do not want the patches to move). Anyway, I finally decided to use the mesquiteMotionSolver that is in the dynamicTopoFvMesh library of Sandeep. I use the 2.3 port of the library, compiled it with no apparent problem, and I am able to use a prescribed motion on my boundary. Here is my dynamicMeshDict : Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.3.0 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; location "constant"; object dynamicMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dynamicFvMesh dynamicMotionSolverFvMesh; motionSolverLibs ("libmesquiteMotionSolver.so"); solver mesquiteMotionSolver; mesquiteOptions { surfInterval 1; optMetric MeanRatio; objFunction LPtoP; optAlgorithm TrustRegion; tcInner { absGradL2 1e-5; cpuTime 0.05; } //- Power value for the LPtoP objective function pValue 2; power 2; //- Specify a tolerance for the surface-smoothing CG solver tolerance 1e-2; //- Specify number of CG sweeps for surface-smoothing nSweeps 2; fixedValuePatches{ cylinderBasis { type timeVaryingUniformFixedValue; value uniform (0 0 0); outOfBounds repeat; fileName "$FOAM_CASE/values"; } } } Code:
( (0 (0 0 0)) (0.001 (0 0 0)) (0.002 (0.0000104716405696524 0 0)) (0.003 (0.0000104710663911498 0 0)) (0.004 (0.0000104702051430726 0 0)) (0.005 (0.0000104690568490324 0 0)) (... (... ... ...)) (0.996000000000001 (-0.0000000553892191113015 0 0)) (0.997000000000001 (-0.0000000453188323409903 0 0)) (0.998000000000001 (-0.000000035248217367459 0 0)) (0.999000000000001 (-0.000000025177424900838 0 0)) ) I would be glad to find a solution to this because it would allow me to use dynamic deltaT instead of a fixed one. My simulation does have two different states, one where the motion of the wall is really slow, therefore the courant number drops drastically and I could save a lot of time by increasing the deltaT during those states. |
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July 15, 2015, 09:03 |
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#2 |
New Member
Al_th
Join Date: Apr 2015
Posts: 19
Rep Power: 11 |
Anyone please ?
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February 16, 2022, 06:22 |
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#3 |
New Member
Pengcheng Zhang
Join Date: Aug 2021
Posts: 14
Rep Power: 5 |
The prescribed motion of a patch is relatived to deltaT.
Because the value of pointPatchField, which you set in timeVaryingUniformFixedValue, is the relative displacement, not the absolute position of every mesh point. That is, the data you set in "values" file means the displacement vector of every mesh point at every specific time step. |
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