Menu

Discussion Forum

New Discussion
Filtrer

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 The information provided may be out of date.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.

mean curvature in comsol 4.2

Posted 20 juin 2011, 08:22 UTC−4 Computational Fluid Dynamics (CFD), Geometry, Mesh Version 4.2 3 Replies

Christian Kelb
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi!

For a moving-mesh problem I am trying to get the value of the mean curvature of a surface. 'r', like in Comsol 4.1 doesn't seem to work anymore since it says 'unknown variable'.

Can anyone help me?

Best regards,
Christian
3 Replies Last Post 27 juil. 2012, 07:10 UTC−4
Christian Kelb
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 20 juin 2011, 11:30 UTC−4
As a suggestion:

Is there a way to compute the gradient of the normal vector of the surface?
I am unable to find anything in the documentation apart from the formulas I already know.

Best regards,
Christian
As a suggestion: Is there a way to compute the gradient of the normal vector of the surface? I am unable to find anything in the documentation apart from the formulas I already know. Best regards, Christian
Christian Kelb
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 21 juin 2011, 10:50 UTC−4
Ok, next idea:

I discovered, that there is a differential function d(f,x) where f is the derived function and x the derivation direction. I tried to get the gradient of the normal vector as

grad(n) = d(nx,x) + d(ny,y) + d(nz,z)

but this produces zero for me. Am I using the wrong normal vector?
Ok, next idea: I discovered, that there is a differential function d(f,x) where f is the derived function and x the derivation direction. I tried to get the gradient of the normal vector as grad(n) = d(nx,x) + d(ny,y) + d(nz,z) but this produces zero for me. Am I using the wrong normal vector?
Karl Sundermann
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 27 juil. 2012, 07:10 UTC−4
Hello,

You have find the answer for your problem? I've the same. It produces 0 for me too.
You tried weak contribution with divergence theorem? For that the is to calculate the [ ] terms. You see what I mean?
Hello, You have find the answer for your problem? I've the same. It produces 0 for me too. You tried weak contribution with divergence theorem? For that the is to calculate the [ ] terms. You see what I mean?

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content