Why is my COMSOL solution not converging?

In summary, the conversation discusses a problem with convergence in using the incompressible Navier-Stokes model in COMSOL. The error message "Failed to find a solution" is mentioned and the individual has tried various solutions but none have helped. Another person suggests unchecking "p" on the "Solve for" card in Solver Parameters, but the individual is confused as they cannot find this option. Eventually, they realize it is in Solver Manager and are able to fix the problem.
  • #1
yaelgo
3
0
Hello,
I'm a 2nd year student, and I'm trying to get to know COMSOL. I'm starting off by solving simple problems with the incompressible Navier-Stokes model, but I keep having trouble with the convegence of the solution.
I keep getting the following error:

"Failed to find a solution:
The relative error is greater than the relative tolerance.
Returned solution has not converged."

I've tried to solve many problems, but it gives me the same error over and over again.
I've changed the number of iterations, the tolerance and the DOF by remeshing, but nothing seems to help.


If someone here has a usefull advice, I would really appreciate it.

Thanks,
Yael.
 
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  • #2
I had the same problem. Comsol has a problem with pressure calculations in Navier-Stokes physics. You have to uncheck "p" on "Solve for" card in Solver Parameters.
 
  • #3
Thank you!
but I don't really understand what you mean - I can't see "solve for" in the solver parameters.
could you be more specific? what solver are you using?

Thanks,
Yael.
 
  • #4
Sorry, my fault - it's in Solver Manager.
 
  • #5
it works! thanks :)
 

1. What is "Peoblem - COMSOL convergence"?

"Peoblem - COMSOL convergence" refers to a common issue encountered by users of the COMSOL Multiphysics software. It refers to the failure of the software to accurately solve a simulation, resulting in a lack of convergence between the calculated results and the desired solution.

2. What causes "Peoblem - COMSOL convergence"?

There are several possible causes for this issue, including incorrect boundary conditions, meshing errors, and the use of an inappropriate solver or numerical method. In some cases, the problem may also be caused by the complexity of the simulation or the limitations of the hardware being used.

3. How can I troubleshoot "Peoblem - COMSOL convergence"?

To troubleshoot this issue, it is important to carefully review the simulation setup and make sure all boundary conditions are correctly defined. It may also be helpful to simplify the model and refine the mesh to improve convergence. Additionally, changing the solver settings or using a different numerical method may also help resolve the issue.

4. Can "Peoblem - COMSOL convergence" be avoided?

In some cases, yes, "Peoblem - COMSOL convergence" can be avoided by carefully setting up the simulation and using appropriate solver settings. However, in complex simulations, convergence issues may be unavoidable and require careful troubleshooting and refinement of the model.

5. Are there any resources available for further help with "Peoblem - COMSOL convergence"?

Yes, there are several resources available for users experiencing convergence issues with COMSOL Multiphysics. These include user forums, technical support from COMSOL, and online tutorials and guides. It may also be helpful to consult with colleagues or other experts in the field for advice and assistance.

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