Dynamic Mesh Control
Transcript of Dynamic Mesh Control
H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
Dynamic mesh controlDynamic mesh controlDynamic mesh controlDynamic mesh control
• Dynamic mesh control• Deformation• Rotational motion
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
Dynamic mesh related problems
• Motion of object in fluid▫ Body motion with boundaries (wall, ground, free
surface) requires dynamic mesh(alternative solution is overset mesh)
Note: If all the outer boundaries are open, deformation is not needed
• Rotating machine (open test)▫ Moving Reference of Frame (MRF)
• Rotating machine with casing▫ Sliding mesh technique
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
pimpleDyMFoam solver
• movingCone case▫ Mesh: solution of Laplacian solver
• Needs velocity boundary condition of mesh
• wingMotion case▫ snappyHexMesh : meshing▫ simpleFoam : prepare steady flow field▫ pimpleDyMFoam : flow simulation with motion
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
OpenFOAM cases of dynamic mesh
• MRF example▫ incompressible/MRFSimpleFoam/mixerVessel2DStatic mesh in rotating coordinates
• Dynamic mesh example▫ incompressible/pimpleDyMFoam
• movingCone : Defomation of mesh• mixerVesselAMI2D : • wingMotion
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
Arbitrary Mesh Interface (AMI)AMI is for• un-matched/non-conformal cyclic
patch pairs• sliding interfaces, e.g. for rotating
machinery• mapped patches, e.g. for coupling• simulations between separate
mesh regions, such as surface film and bulk flow.
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
Rotating turbine example
• Prepare “Fluent case files” of rotating part and stationery part separatelyInner.cas and outer.cas
• Convert the Fluent case files to OpenFOAMcase directory▫ fluentMeshToFoam –writeZone –writeSets
inner.cas▫ fluentMeshToFoam –writeZone –writeSets
outer.cas
Point is providing “two cases”6
H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
• Merge two meshes▫ $ mergeMesh inner outer
It creates merged mesh in run/inner/1e-5 (something like that)
Directory name is the "first time step" determined by controlDict
• Create rotating simulation case▫ Prepare mycase/system and mycase/constant▫ Copy inner/1e-5/polymesh to the new case
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
• Create cellZone data in the new case▫ splitMeshRegions -makeCellZones –overwrite
• Edit constant/polymesh/boundary and set AMI patches
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H. AKIMOTO, Division of Ocean Systems Engineering (OSE), Korea Advanced Institute of Science and Technology
inner-AMI{
type cyclicAMI;nFaces 16;startFace 304;matchTolerance 0.0001;neighbourPatch outer-AMI;transform noOrdering;
}
outer-AMI{
type cyclicAMI;nFaces 16;startFace 320;matchTolerance 0.0001;neighbourPatch inner-AMI;transform noOrdering;
}
Then edit boundary condition and run the simulation
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