Register to reply

Problem with a boundary condition in Comsol

Share this thread:
ivanguru
#1
Feb21-09, 11:31 AM
P: 1
hi, i'm a chemical engineering student with a little problem with Comsol multiphysics;
in practice, i have to solve a problem of diffusion in a solid sphere.
after drawing the domain, i have to set a boundary condition on sphere's surfaces.
this condition, for my problem, is FLUX=Kc(Cb-C) and Cb (bulk concentration) is

proportional to an integration coupling variable, that i have previously fixed
In particular, Cb is equal to costant * mass_released, where mass_released is equal

to volume integral of C0 (initial concentration) minus C

After setting all variables and running simulation, it gives me an error referred to

evaluation of variable Cb
I think the problem is that it's difficult to use in a boundary condition a variable that

changes during simulation (in fact it is time dependent)..


I hope someone can help me, have a nice day!!!
Phys.Org News Partner Science news on Phys.org
Study links polar vortex chills to melting sea ice
Lab unveil new nano-sized synthetic scaffolding technique
Cool calculations for cold atoms: New theory of universal three-body encounters

Register to reply

Related Discussions
Comsol moving boundary+ Heat Transfer Mechanical Engineering 8
Comsol boundary conditions between two conductors Math & Science Software 0
Heat conduction in bars: varying the boundary condition. Harmonics problem Calculus & Beyond Homework 5
Boundary Condition Problem Advanced Physics Homework 4
Boundary condition problem Calculus & Beyond Homework 0