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October 2, 2018, 16:43 |
cyclicAMI - kOmegaSST - divergence issue
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#1 |
Senior Member
cyln
Join Date: Jul 2016
Posts: 102
Rep Power: 10 |
Hello, I am running a transient RANS simulation using pimpleFoam on OF4.1. My grid is a combination of non-comformal unstructured and structured grids. I defined an interface between the two grids using cyclicAMI (noOrdering).
I have completed my laminar simulation as it had been running without any issues. However, whenever I switch to kOmegaSST turbulence model, my simulation diverges whenever turbulence transport equations are solved for the first time. Before, I was using kOmegaSST for the same case with fully unstructured grid (without cyclicAMI) and it had been running for several thousand time steps. So, I know the divergence is related to cyclicAMI (noOrdering). I tried kEpsilon and kOmega, and I still got divergence. As for discretization schemes, I am using linearUpwind for U, k and omega. My boundary conditions are given below. Can anybody suggest me why my turbulent simulation (with cyclicAMI) is diverging? polyMesh/boundary Code:
7 ( FARFIELD { type patch; nFaces 65021; startFace 67971616; } OUTLET { type patch; nFaces 6249; startFace 68036637; } BODY { type wall; inGroups 1(wall); nFaces 158614; startFace 68042886; } INTEROUTT2 { type cyclicAMI; inGroups 1(cyclicAMI); nFaces 40559; startFace 68201500; matchTolerance 0.001; transform noOrdering; neighbourPatch INTEROUT2; } INTEROUT2 { type cyclicAMI; inGroups 1(cyclicAMI); nFaces 53599; startFace 68242059; matchTolerance 0.001; transform noOrdering; neighbourPatch INTEROUTT2; } INTERFACET2 { type cyclicAMI; inGroups 1(cyclicAMI); nFaces 249569; startFace 68295658; matchTolerance 0.001; transform noOrdering; neighbourPatch INTERFACE2; } INTERFACE2 { type cyclicAMI; inGroups 1(cyclicAMI); nFaces 308799; startFace 68545227; matchTolerance 0.001; transform noOrdering; neighbourPatch INTERFACET2; } Code:
dimensions [0 1 -1 0 0 0 0]; internalField uniform (-40 0 0); boundaryField { FARFIELD { type fixedValue; value uniform (-40 0 0); } BODY { type noSlip; } OUTLET { type zeroGradient; } INTEROUTT2 { type cyclicAMI; } INTEROUT2 { type cyclicAMI; } INTERFACET2 { type cyclicAMI; } INTERFACE2 { type cyclicAMI; } } Code:
internalField uniform 0.0; boundaryField { FARFIELD { type zeroGradient; } BODY { type zeroGradient; } OUTLET { type fixedValue; value uniform 0.0; } INTEROUTT2 { type cyclicAMI; } INTEROUT2 { type cyclicAMI; } INTERFACET2 { type cyclicAMI; } INTERFACE2 { type cyclicAMI; } } Code:
internalField uniform 1e-6; boundaryField { FARFIELD { type fixedValue; value uniform 1e-6; } BODY { type fixedValue; value uniform 0.0; } OUTLET { type zeroGradient; } INTEROUTT2 { type cyclicAMI; } INTEROUT2 { type cyclicAMI; } INTERFACET2 { type cyclicAMI; } INTERFACE2 { type cyclicAMI; } Code:
internalField uniform 0.55 ; boundaryField { FARFIELD { type fixedValue; value uniform 0.55; // 0.0017; // 22.36; } BODY { type fixedValue; value uniform 241632653; } OUTLET { type zeroGradient; } INTEROUTT2 { type cyclicAMI; } INTEROUT2 { type cyclicAMI; } INTERFACET2 { type cyclicAMI; } INTERFACE2 { type cyclicAMI; } Code:
internalField uniform 0; boundaryField { FARFIELD { type calculated; value uniform 0; } OUTLET { type calculated; value uniform 0; } BODY { type fixedValue; value uniform 0; } INTEROUTT2 { type cyclicAMI; } INTEROUT2 { type cyclicAMI; } INTERFACET2 { type cyclicAMI; } INTERFACE2 { type cyclicAMI; } |
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October 5, 2018, 11:06 |
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#2 |
Senior Member
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Hi,
I am guessing (as you did not show the exact output) that you have a divide by zero at the cyclicAMI interfaces. The reason is that you have no value entry and this may mean that a default of 0 is used. Just give a value equal to your internalField and rerun? Regards, Tom |
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