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.
Rookie question: Calculation of eigenmodes
Posted 24.02.2011, 09:58 GMT-5 0 Replies
Please login with a confirmed email address before reporting spam
first of all sorry for my probably quite easy question, but I'm just started to used Comsol and I'm not able to solve my problem with the help of the documentation and hints found in the net.
Just for getting used of using Comsol I want to calculate the eigenmode of dylinderical wire. For it I choose in the RF module -> Electromagnetic Waves -> Eigenfrequency analysis, as Geometry I choose a block (dimension 1e-5, 1e-6,1e-6) with a cylinder (oriented in x-direction, length 1e-5 radius 1e-7) in the center. The dielectric properties of the cylinder are given by 1-omegap^2/omega^2 with omegap=1.4e16 and omega=2*pi*3e8/lambd0_rfw (all defined in Options->Expressions->Scalar Expressions). In Solver Parameter -> Eigenfrequency-> Eigenfrequency I have choosen Eigenvalue linearizion point as 0.5+omegap. If I now try to solve the model I received the message
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 stiffness matrix.
There are 20 equations giving NaN/Inf in the matrix rows for the variable tExEyEz10
at coordinates: (5e-06,-8.50756e-08,-5.17434e-08), (5e-06,-5.17422e-08,-8.50767e-08), (5e-06,5.17434e-08,-8.50756e-08), (5e-06,8.50767e-08,-5.17422e-08), (5e-06,5.17434e-08,8.50756e-08), ...
There are 4 equations giving NaN/Inf in the matrix rows for the variable tExEyEz20
at coordinates: (5e-06,5.90095e-13,-5.17428e-08), (5e-06,5.90095e-13,5.17428e-08), (-5e-06,5.90095e-13,5.17428e-08), (-5e-06,5.90095e-13,-5.17428e-08), ...
There are 4 equations giving NaN/Inf in the matrix rows for the variable tExEyEz21
at coordinates: (5e-06,5.90095e-13,-5.17428e-08), (5e-06,5.90095e-13,5.17428e-08), (-5e-06,5.90095e-13,5.17428e-08), (-5e-06,5.90095e-13,-5.17428e-08), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns
)
at com.femlab.solver.FlSolver.femEig(Native Method)
at com.femlab.solver.FemEig.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 would be very thankful for any hint,
Frank
Hello Frank Meyer
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.