Menu

Discussion Forum

New Discussion
Filtra

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 The information provided may be out of date.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.

Attempting to find total drag force on an object

Posted 7 feb 2012, 20:42 GMT-5 Fluid & Heat, Computational Fluid Dynamics (CFD), Results & Visualization Version 4.2a 2 Replies

Peter Malloy
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I'm fairly new to COMSOL and haven't been able to find any really detailed guides on how to go about this. I've currently got two problems that I can't figure out how to solve.

1) When I solve the simulation, I get an error reading:

"Cannot evaluate expression.
Failed to evaluate variable.
- Variable: mod1.fsi.mises
- Geometry: 1
- Boundary: 22
Failed to evaluate expression.
- Expression: mod1.fsi.mises
- Plot: surf1 (Surface)"

Boundary 22 is my inlet flow. I'm not sure how big of a deal this is because I don't believe I need the von mises stress for what I'm trying to solve for. What I'm trying to figure out is how to get...

2) The reaction forces. How can I find the forces on the solid part of my model? And how do I go about integrating them to find the total drag force?

Thanks a ton
2 Replies Last Post 2 apr 2013, 23:35 GMT-4
Peter Malloy
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 8 feb 2012, 16:21 GMT-5
Any help?
Any help?
Vahid Babakeshizadeh
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2 apr 2013, 23:35 GMT-4
Hi

you better explain how you did the modeling or even better to upload your file. This way some one may help!

You probably missed something during your modeling! Check the material section. You may need to add the value of some property!

Good Luck
Hi you better explain how you did the modeling or even better to upload your file. This way some one may help! You probably missed something during your modeling! Check the material section. You may need to add the value of some property! Good Luck

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