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Spatial derivative of a field variable
Posted 21.07.2015, 20:22 GMT-4 Parameters, Variables, & Functions Version 5.1 0 Replies
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I am new to COMSOL and I am now using version 5.1. To simulate my problem I use the coefficient form in equation based modelling interface. To be specific, here I provide a simplified example:
I want to solve for c which is governed by the diffusion equation:
dc/dt=nabla.(D*nabla c)+R
However, this is a multi-physics problem and is coupled with another field variable p governed by:
dp/dt=nabla.(L*nabla p)
To achieve the coupling, the first equation is written, for example,
dc/dt=nabla.(D*nabla c)+nabla p
My problem is , how to represent nabla p, which is the spatial derivatives of the field variable p, in COMSOL? I know the operator d(f(x),x) gives me the derivative df/dx, but p is not a function of x but rather a field variable. Any suggestion will be gratefully appreciated.
Thank you!
Hello Weijie Mai
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