Menu

Discussion Forum

New Discussion
Filter

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 The information provided may be out of date.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.

element order and convergence

Posted Jul 27, 2011, 7:43 p.m. EDT Studies & Solvers Version 4.1 1 Reply

Sirisha Govindaraju
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I have a FSI problem that converges when I use first order elements for pressure and velocity and second order for displacements. But I am not happy with the results I am seeing. Hence I changed the element order.

I am using second order elements for the velocity and displacement and first order for pressure. Now the problem is not converging.

It should not be behaving this way because I think that increasing the order of the element should give better convergence. Am I wrong? Did anybody face a similar problem?

Thanks,
Sirisha
1 Reply Last Post Apr 12, 2014, 8:17 a.m. EDT
COMSOL Moderator

Hello Sirisha Govindaraju

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Chang-Ho Han
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Apr 12, 2014, 8:17 a.m. EDT
Hi.

Check the Reynolds number for the fluid flow.
If the Reynolds number is high, the convective term in Navier-Stokes eqn is dominant, which is a nonlinear term.
Then, it's better to solve with first order element in velocity.
Second order element in velocity is good when the diffusive term is dominant.
Hi. Check the Reynolds number for the fluid flow. If the Reynolds number is high, the convective term in Navier-Stokes eqn is dominant, which is a nonlinear term. Then, it's better to solve with first order element in velocity. Second order element in velocity is good when the diffusive term is dominant.

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