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Classic PDE Helmholtz Equation

Posted 29 janv. 2013, 11:51 UTC−5 Modeling Tools & Definitions, Parameters, Variables, & Functions Version 3.5a 0 Replies

Ken Thomas
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I am trying to use the 3D Classic PDE for Helmholtz Equation for diffusion through a cylinder. I have not used Comsol much before, and I am a little confused on the Sub-domain/boundary conditions.

The sub-domain settings ask for a diffusion and absorption coefficient. It does not ask for units though. Does this mean it will work for any consistent set of units, or does it need to be in m^2/s and m^-1 respectivly?

And for the boundary conditions, it offers either Dirichlet or Neumann boundary conditions. I believe I want Dirichlet for the area my flux is coming from. The equation listed is h(dot)u=r, and available coefficients are q, g, h, and r. What exactly are each of these variables, and how do q and g effect the equation? And again, are specific units expected, or do I just need to make sure they are consistent throughout?

Sorry if this is a very beginner question, but I don't even know where to start.

Thank you for any help.
0 Replies Last Post 29 janv. 2013, 11:51 UTC−5
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