[Lesh2Flash]

Hi Everyone,

I want to solve a (nonlinear) Reaction-Diffusion problem using OpenFOAM. The equations are of the following Form:

- There are some bulk species which can diffuse through the whole domain and undergo simple reactions (e.g. degradation of one species as described by the term -k*u_i with degradation rate k). The governing equation for the i-th bulk species would then have the form d/dt*u_i=D_i*nabla^2 *u_i + R(u_i). This is basically just a simple transport equation (diffusion + source term) and could be solved with the ScalarTransportFoam solver.

- I also would like to define membrane species which "live" on a predefined boundary of the domain. In other words, these membrane species can only diffuse and react on a particular boundary of the simulation domain, i.e. the transport equation has basically the same form as mentioned above but is constrained to a specific boundary. And here comes now the tricky part: Bulk and Membrane species can react with each other, i.e. I want to couple the transport equations by a flux boundary condition (also known as robin boundary condition) which states that everything that flows out of the bulk reacts on the membrane into some other component, mathematically this flux condition is of the form J_i =-D_i*nabla(u_i)= -f(u_i), where the function f(u_i) depends on the species concentration and is in general nonlinear.

My question is whether OpenFOAM already provides the tools to set up such a simulation? I couldn't find a similiar problem in the documentation or here on the forum, so I really would appreciate any help as Im not a OpenFOAM specialist. I think the ScalarTransportFoam is a very good starting point, but Im struggling with the diffusion constraint + the robin boundary condition.


Thank you very much for the help in advance!

Best,

Lesh