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andreasp October 28, 2013 04:38
Boundary condition at material interface
 
Hi everyone!

I am stuck formulating the correct boundary condition at a material interface in a pure mass transport (diffusion) problem.

I have two domains with different diffusion coefficients. At their interface, I want to ensure both continuity of the concentration profile and of diffusive fluxes:

c_1 = c_2

\mathbf{n}_1 \cdot (D_1 \nabla c_1) = \mathbf{n}_2 \cdot (D_2 \nabla c_2)

Currently I am pretty confused, so I have different questions:
1.) Are these conditions correct (in a physical sense)?
2.) Can I really enforce both at the same time? Wouldn't this result in an overdetermined system?
3.) Or does enforcing one of these automatically result in the other one being fulfilled as well?

Thanks in advance for any help!

Best,
Andreas

t.oliveira March 11, 2016 06:08
[it is an old discussion, but may be useful for someone]

Hi Andreas,

Shouldn't the conditions be the following?

c_1 = c_2

D_1 \nabla c_1 =D_2 \nabla c_2


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