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 The information provided may be out of date.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.

Error: 7248

Please login with a confirmed email address before reporting spam

Hello,

I need simulate a turbulent pipe flow in comsol3.5a and the viscosity is not constant.
The viscosity depends on the shear rate and when I try to introduce the expression in Global Expressions as
Visc= m[Pa*s]*(Shear[s]+epsilon)^n and Shear = sqrt(0.5*(4*ur^2+2*(uz+vr)^2+4*vz^2+4*u^2/(r+eps)^2)+eps)
I have the error:

"Error: 7248
Undefined value found.

Exception:
com.femlab.jni.FlNativeException: Undefined value found Solvermodel
Messages:
Undefined value found Solvermodel

Stack trace:
at solvermodel.cpp, row 1837, (Undefined value found in the equation residual vector.
There are 2274 degrees of freedom giving NaN/Inf in the vector for the variable logd
at coordinates: (0.0352288,0.494039), (0.0366644,0.495068), (0.0354093,0.495682), (0.0381,0.496096), (0.0368449,0.496711), ...
There are 2270 degrees of freedom giving NaN/Inf in the vector for the variable logk
at coordinates: (0.0352288,0.494039), (0.0366644,0.495068), (0.0354093,0.495682), (0.0381,0.496096), (0.0368449,0.496711), ...
)
at com.femlab.solver.FlSolver.femStatic(Native Method)
at com.femlab.solver.FemStatic.run(Unknown Source)
at com.femlab.server.FlRunner.run(Unknown Source)
at com.femlab.util.i.run(Unknown Source)
at com.femlab.util.aa.run(Unknown Source)"

I don't know what I can do to solve this problem. Someone can help me...

Carla

0 Replies Last Post 22.12.2011, 06:02 GMT-5
COMSOL Moderator

Hello Carla Cotas

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.

Suggested Content