Post Processing of an Electrostatic Field

[Baoyun Ge]

Dear All,

I am using dealii to solve the electrostatic field governed by Laplace's equation. Right now I have the solution vector, which contains the electrical potential information throughout all the degrees of freedom. I am stuck at the post processing phase, where I want to evaluate the charges on the electrodes. The way I am seeking it is in two steps:

1) evaluating electric field using the electrical potential information;
2) integrating electric field over the surface enclosing the electrode under consideration (Gauss's Law).

Unfortunately, I haven't found too much useful information to guide me to accomplish these two steps. Any information and guidance from you guys would be appreciated!

Thanks!
Baoyun Ge

[Wolfgang Bangerth]

Baoyun, the electrical field is just the gradient of the potential, so this is
easy to evaluate via FEValues::get_function_gradients(). For the integration,
what surface do you want to integrate over? Any surface? A surface that is
composed of faces of cells? The former is difficult, the latter easy to
achieve with the FEFaceValues class.

Best
W.

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Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[Baoyun Ge]

Hi Professor Bangerth,

Thanks for the quick reply! According to your guidance, I found more useful posts about this topic and finally I referenced the heat flux example and got it work.

By the way, I really appreciate you guys' work on the dealii package. It's a great FEA tool!

Best,
Baoyun Ge