Undefined value found in the equation residual vector.
I am trying to model a pem fuel cell. Although I have entered all parameters and values, i have some errors as follows; Undefined value found. - Detail: Undefined value found in the equation residual...
View Articlecoupling of two phase free flow-Darcy flow
Hello Recently i have been trying to solve such a problem: how to couple free flow and Darcy flow for two phase fluid by Comsol in other to simulate the real situation of fluid flow freely near the...
View Articlesolving two partial differential equations nonlinear in comsol?
Hi, I want to solve two pde nonlinear with two variables (please find in the attachment file) with the constants. For solve, i tried to use the heat equation and PDE (c) in two step: step 1: solve...
View ArticleTeflon Die Extrusion
I am new to COMSOL and need some help/advise from someone with experience. This simulation is modeling a 25% glass filled-teflon billet extrusion through a steel die (1/4 of the entire model). I added...
View Articledesigning of capacitor which must be capable of lightning harvesting
I am trying to design a capacitor model under different dielectric materials and to analyze the behavior of capacitor. Can any one tell me how can i change or model capacitor with different dielectrics...
View ArticleHow does one change undesired defaults?
There are several defaults that are never my preference. Would like to change them – so sweeps go as desired when I forget to set them as desired, which usually gets over-ridden anyway with something...
View ArticleJoule heating and PDE interface - Error: Failed to find consistent initial...
Hi All. I am using v.4.1 and the Joule-heating and PDE-general form interfaces for a time-dependent study. I want to use joule-heating to solve for temperature evolution vs. time, as well as the PDE...
View ArticleError
Hi everyone!! i had following error in my model.. can any one say what it is?? Unknown function or operator. - Name: mod1.mf.mtcd1.ccc1.int_term
View ArticleExport of results in parametric sweep
Hello all! Let's say that I have a parametric sweep of a parameter A in range(1,1,15). I want to see how the sweep in A affects another parameter, let's say B. In every step I take a result for B, how...
View ArticleSimple optimization in comsol 5.0
Hey Everyone I'm trying to do A simple optimization in Comsol 5.0 However it keeps giving me an error. In the attached image you can se how I set it up. A quick summary: under definitions I have...
View ArticleModelling a Quantum Cascade Laser via Copper Heat Sink and GaAs
Apologies for the long post. The model is attached in the attachments. A simple drawing of what I am trying to model is shown in attachment (1). I am trying to simulate a type of Quantum Cascade Laser,...
View Articlehigh-end computer-guidance garbage
A couple weeks ago we asked for some guidance from COMSOL on a computer upgrade - for running big problems - 10 to 20M DOFs. We were directed to this pagewww.comsol.com/support/knowledgebase/866/ where...
View ArticleSimulating a solid cylinder with a transient displacement point source to get...
Hello, I have been trying to simulate a cylindrical model using structural mechanics(time dependent) with a transient displacement point source (0.00005*sin(2*3.14*3000*t)*e^(-((t-t0)^2)/(2*(sigma^2)))...
View ArticleJava Runtime Environment error
Getting following error, A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x0000003da3efbc6c, pid=6909, tid=46912497239488 # # JRE version: 6.0_20-b02 # Java VM:...
View ArticleOne boundary with two boundary conditions (Neumann and Dirichlet)
Please help me to understand about this issue. I have a system of two PDE equations with two variables (u1, u2) need to be solved in General Form. On a boundary 1, for example, I set up a Neumann...
View ArticleBasic GaN TFT Simulation, Mesh error
Hi everyone, I am new in Comsol, so probably my issue will sound funny to you, however I could not solve that problem and want your help. I want to simulate a basic thin film transistor (TFT) in 3D in...
View ArticleJoule Heating and Thermal Expansion
Hello, I'm trying to solve the problem of Joule Heating and Thermal Expansion by applying current via terminal. Somehow I'm getting the following error."Failed to find a solution. Singular matrix....
View ArticleLight Propagation in Tissue
i just want to simulate the propagation of monochromatic light (800nm) in a 3 Layer tissue model 3D. Does anyone know a working Comsol solution? Problem: to many elements with this wavelength. Setup: 3...
View Articlebaffled duct - PML 3D PROBLEM
Hello every one, I’d like to excite a cylindrical waveguide (rigid in one face and flanged in the other one) with a monopole located in M(x,y,z) and compute the pressure inside the duct. Also, compute...
View ArticleImplementing a two-temperature-model (electronic/lattice) for fast...
Hi I am trying to solve a similar problem and I am using PDE (c) interface. Anyway, how did you try to solve it? Thanks!
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