Hello!
I am using the FEBioChem plugin to model X-direction transport of a neutral solute. There are two compartments in a closed box separated by a thin membrane, having different initial concentrations. There is a constant concentration flux at both sides of the membrane; the same amount of solute is transported from one compartment to the other. RD_BiasedMesh.feb
So, there should be an increase and decrease in concentrations accordingly, the minimum being zero in one part when all of the solute has been removed from it.
However, I get to see negative concentrations, some being very high in magnitude for large flux values. I read somewhere that this happens because of coarse mesh near the boundaries of concentration jump. So, I tried to refine the mesh. RD_BiasedMeshFiner.feb
Unfortunately, the problem is not solved. Negative concentrations affect the equilibrium values. Please suggest if there are other causes so that I can make suitable corrections in my model.
I also notice a concentration gradient along X-direction in the membrane. So, I am wondering if there is an inherent diffusion in the system inspite of the boundary conditions imposed?
Thank you,
Abha
I am using the FEBioChem plugin to model X-direction transport of a neutral solute. There are two compartments in a closed box separated by a thin membrane, having different initial concentrations. There is a constant concentration flux at both sides of the membrane; the same amount of solute is transported from one compartment to the other. RD_BiasedMesh.feb
So, there should be an increase and decrease in concentrations accordingly, the minimum being zero in one part when all of the solute has been removed from it.
However, I get to see negative concentrations, some being very high in magnitude for large flux values. I read somewhere that this happens because of coarse mesh near the boundaries of concentration jump. So, I tried to refine the mesh. RD_BiasedMeshFiner.feb
Unfortunately, the problem is not solved. Negative concentrations affect the equilibrium values. Please suggest if there are other causes so that I can make suitable corrections in my model.
I also notice a concentration gradient along X-direction in the membrane. So, I am wondering if there is an inherent diffusion in the system inspite of the boundary conditions imposed?
Thank you,
Abha