Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Varying concentration on surface of a sphere
Posted Jun 10, 2015, 4:38 a.m. EDT Chemical Reaction Engineering Version 4.3 2 Replies
Please login with a confirmed email address before reporting spam
Hello,
I'm working in COMSOL 4.3a with the Transport of Diluted Species module. I have created a simple sphere and would like to model outward flux of a certain species given an external boundary condition (initial surface concentration). As a test to understand how COMSOL does its calculations, I want to make one half of the sphere have a different initial surface concentration than the other half.
Since the Transport of Diluted Species module cannot be set to evaluate on the boundary only, I am storing the concentration (c) defined in Initial Values in variables that are then used in equations also defined in the same Variables group. One variable simply multiplies c by 10 as a test to see if there is any difference in the final concentration. For both variable groups, Geometric Entity Level is set to the respective boundaries (i.e. each half of the sphere).
When I run the time-dependent study, the surface concentration ends up being uniform all the way around even though I tried to make one half of the sphere have a different initial surface concentration. Any suggestions would be helpful!
Thanks,
Sam
I'm working in COMSOL 4.3a with the Transport of Diluted Species module. I have created a simple sphere and would like to model outward flux of a certain species given an external boundary condition (initial surface concentration). As a test to understand how COMSOL does its calculations, I want to make one half of the sphere have a different initial surface concentration than the other half.
Since the Transport of Diluted Species module cannot be set to evaluate on the boundary only, I am storing the concentration (c) defined in Initial Values in variables that are then used in equations also defined in the same Variables group. One variable simply multiplies c by 10 as a test to see if there is any difference in the final concentration. For both variable groups, Geometric Entity Level is set to the respective boundaries (i.e. each half of the sphere).
When I run the time-dependent study, the surface concentration ends up being uniform all the way around even though I tried to make one half of the sphere have a different initial surface concentration. Any suggestions would be helpful!
Thanks,
Sam
2 Replies Last Post Jun 10, 2015, 10:55 a.m. EDT
Please login with a confirmed email address before reporting spam
Posted:
9 years ago
I made some progress by adding two Concentration boundary conditions under the Transport of Diluted Species module that I can define each half of the sphere with. This might be what I was looking for.
Please login with a confirmed email address before reporting spam
Posted:
9 years ago
Well that wasn't it. Those boundary conditions just set the concentration on the surface to a specific value.