Lastly, the number of fvDOM directions required would probably be prohibitively high.
Explicit treatment of this coupling would therefore be extremely slow to converge. A ray may cross the mesh many times, particularly if the wedge angle is small, changing variable each time. The first is that there is really no structure for this sort of coupling. There are a number of problems with this. With fvDOM, this would mean coupling between the variables that represent the different ray directions. The missing behaviour is a transformation of the ray variable across the coupled patches i.e., when a ray leaves one side, it enters again from the other side, with it's direction modified to account for the transformation between the patches. The error, as you calculate it will be small when the cylinders are close to the same size, and will tend to 100% as the inner cylinder becomes small. The result you are getting is close to the analytic solution for infinite flat plates. Hence, in the validation case attached, there could be some ray loss? I am not sure if I am putting it in right words.ĬhtMultiRegionSimpleFoam, fvDOM, Heat transfer, radiation
OPENFOAM WEDGE PATCH PATCH
The wedge patch does not participate in radiation, yet, fvDOM solves for transport across them since nTheta !=0 leading to loss of rays? As a ramification of this - solver crashes if you set nTheta =0. Hence the radiation problem is treated as 3D - requiring both nTheta and nPhi in fvDOM. I am not sure what could be a fix but I suspect the solution might lie in how fvDOM deals with wedge patches:įvDOM uses strategy based on nSolutionD as,įrom polyMesh::nsolutionD, for wedge type geometry, nSolutionD is returned as 3. For more complex problems I'm observing this deviation > 25%. This problem exacerbates with higher model complexity. With this approach I get values closer to analytical (about 2% error). I tried alternate approach with symmetry patches and semi-circular model with extrusion model "sector" instead of "wedge".
Radiative analytical heat flux from "hot" wall comes out to 260.9 kW/m2.Īxisymmetric test case under-predicts the heat flux (15% error) (wedge patch). I tried a validation problem with fvDOM on axisymmetric case. 0002759: fvDOM with wedge patch gives inaccurate heat flux calculation
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