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.

Direct- Fully Coupled Solver [Strange Behavior]

Please login with a confirmed email address before reporting spam

Dear All

I´m working on a Natural Convection Tower model. It has the Heat Transfer and Low Re K-e CFD interfaces. And I am using Time Dependent, Direct Fully Coupled method.

I undestand that reciprocal of step size is the indicator of convergence velocity, and we all wish it to be very small. The issue I have been observating, is that every once I pause the computing process to check on the actual results on the heat transfer and flow parameters. And then I continue with the calculation, convergence of several time steps accelerate and then the reciprocal time step rises again and the convergence get stuck again. Why is this happening, every time I pause the calculation, and then continue it, time and the modeling go foreward to an aparent local time convergence of the variables of the flow . This only for a few time, then reciprocal indicator go up again. Can I rely on the results of a problem solved by this procedure?? ( pause, continue). Is there a numerical reason, related with the algorithms of the solvers wich can explain this solver behaviour.


Thank you all.

0 Replies Last Post Feb 28, 2017, 4:54 p.m. EST
COMSOL Moderator

Hello David Vieyra

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.

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.