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 The information provided may be out of date.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.

Laminar flow module Problem

Please login with a confirmed email address before reporting spam

Hello everyone,

I have a simple simulation with just laminar flow module.
I have a circular channel (radius 50micrometer) geometry with water in it.
I have a laminar inflow with 2.5m/s (Re=250) at inlet and 0 pressure at outlet.
with discretization on P2+P1 but my file does not converge, what should I do?
I have attached my comsol file (version 4.4)


1 Reply Last Post 2017年1月2日 GMT-5 09:14
Michael Rembe Certified Consultant

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 2017年1月2日 GMT-5 09:14
Hey Siamak,

I wish you a happy new year!

1. check your boundary and initial conditions! There should be no discontinuity.
2. Use the stationary solver combined with a parameter to ramp up the (inflow) boundary condition.
or
3. Use the time dependent solver and the step function step(t) to ramp up the (inflow) boundary condition.

4. Check the solution during solving.

Best regards
Michael
Hey Siamak, I wish you a happy new year! 1. check your boundary and initial conditions! There should be no discontinuity. 2. Use the stationary solver combined with a parameter to ramp up the (inflow) boundary condition. or 3. Use the time dependent solver and the step function step(t) to ramp up the (inflow) boundary condition. 4. Check the solution during solving. Best regards Michael

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.