[andreasp]

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:





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