dynamic mesh control
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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
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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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