Learning Forum

[wrbulat]

Hi Leon,

Dave raised some good points. Actually, if I were to attempt such a thing I might even stick to direct generation and leave solid modeling out of your mesh coarsening procedure. But before diving into details on how that might be done, I have a concern...

You mentioned doing this coarsening procedure "as the calculation progresses". Do you mean you intend to do it while the solution executes? I didn't know such a thing was possible. Once the system matrices are formed at the beginning of the solution (based on the initial mesh), I'm quite certain that the model can't be changed in this manner. There are features with functionalities similar to what you are attempting - element birth and death and nonlinear adaptive meshing come to mind - but if I understand your objective correctly, I don't really see a way to change the model (elements, mesh, nodal connectivity) during solution. 

If might help if you can tell us the reason you want to coarsen the mesh during a thermal transient. For some reason your description reminds me of an idiosyncracy not uncommon to thermal transients in which boundary conditions change suddenly (thermal undershoot/spurious oscillations). Among the tricks for addressing the occurence of thermal undershoot is refining the mesh in the depth direction at the surface experiencing the sudden change (the mesh is typically coasened with increasing distance from the surface, rather like "inflation" meshing that the CFD folks use to resolve steep field gradients at no-slip surfaces). Does the reason you want to do this have anything to do with sudden exposure to severe thermal boundary conditions?

--Bill