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Neumann Boundary Conditions in General PDE Module Comsol 3.5

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Hello,

I have a general question. I have implemented a set of general PDEs in COMSOL. Two of the PDEs describe particle motion of two species via particle continuity equations in a processing reactor. I solve these two equations along with other PDEs transiently. I noticed after letting the simulation run that at certain locations my neumann boundary conditions were not being satisfied.

For instance, I have a variable 'alpha' that changes in time. This 'alpha' represents the flux at the surface at that specific instance for both species. As such I specified the neumann condition to state the normal flux is equivalent to 'alpha' in my boundary settings for both species PDEs.

Can someone in general explain to me in what instances of FEM modeling or in COMSOL do the neumann boundary conditions need not be satisfied to reach a "solution"? Does this hint towards a numerical instability or physical misinterpretation of the problem? If the problem is my lack of understanding of how neumann boundary conditions are implemented then please direct me to the proper reference or documentation. Thank you.

-David




0 Replies Last Post 2010年9月27日 GMT-4 09:53
COMSOL Moderator

Hello David Urrabazo

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