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.

Two solver steps in time depend. study

Please login with a confirmed email address before reporting spam

I am running a time dependent study. When I try and run for long times, i.e. greater than 5 s, it does not converge. However, if I run a solver step until ~0.1 s and then feed that result in as the initial condition in a second step in the solver, I can run it to longer times, i.e. 100 s. The solutions seem reasonable.

My question is: Is this an appropriate method to getting a simulation to converge?

Thank you

2 Replies Last Post 22 août 2017, 14:09 UTC−4
Jeff Hiller COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 7 years ago 22 août 2017, 13:58 UTC−4
Hello Lawrence,
Please see my colleague's contribution to the following thread for an explanation why your model behaves differently depending on the end time.
www.comsol.com/community/forums/general/thread/108101
As that post suggests, you should be able to get convergence in a single solver step by adjusting the settings as he describes.
Best,
Jeff
Hello Lawrence, Please see my colleague's contribution to the following thread for an explanation why your model behaves differently depending on the end time. https://www.comsol.com/community/forums/general/thread/108101 As that post suggests, you should be able to get convergence in a single solver step by adjusting the settings as he describes. Best, Jeff

Please login with a confirmed email address before reporting spam

Posted: 7 years ago 22 août 2017, 14:09 UTC−4
Dear Jeff,

Thank you for directing me to this post.

Decreasing the "fraction of initial step" worked perfectly. I can now use a single solver step.

Best,
Lawrence
Dear Jeff, Thank you for directing me to this post. Decreasing the "fraction of initial step" worked perfectly. I can now use a single solver step. Best, Lawrence

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.