why does "Undefined value found in the stiffness matrix" means?
I'm trying to simulate Photonic crystal. As far as I know, there is no need for me to know the stiffness of material in the crystal. However, when I click "compute", comsol always screen error message...
View ArticleProblems with parametric sweep
I have a model that I want to investigate with differens values on at least one of the design variables. If I change the variables value manually and compute, there is no problem but if i use variable...
View Article3D graphics Problem and Cantilever Beam Error
Hello, I have attached my model. I have 2 problems. I am simply trying to make a cantilever beam but I get an error. Solver failed to find a solution. In fact it is a simple mechanism. Also, I can not...
View ArticleCoaxial port
What mode of the wave does the coaxial port excite? It does not give options of the modes to be excited. Please help!
View ArticleUpdate 1 for COMSOL Multiphysics 4.3b is now available!
Hello, Update 1 for version 4.3b of COMSOL Multiphysics contains lots of feature and stability enhancements, it can now be downloaded at: www.comsol.com/support/updates/comsol43bp1 If you have not...
View Articlecreating a materials function that change at the space ot a solid 3d elementes
hello, i have a problem with my model i want to change the materials properties ( young modulus ) every iteration without change the model geometry. for example a 3d slab (one block elements) and i...
View ArticleInputting Temperature Dependent Material Properties
Hi everyone, I'm new to comsol and still learning so my question might not be very difficult. I am trying to input the thermal expansion material properties which are temperature dependent. My model...
View ArticleNavier-Stokes Simulation using Coefficient Form PDE
Hi: I need to simulate fluid flow in a triangular duct, but I need to run it on a high reynold number. The problem is that when I run the model using the default "Laminar Flow" physics tab, I need a...
View ArticleIll-conditioned preconditioner
Hello, I am getting this error. Can someone please explain what is the reason of this error and how can I fix it? Thank you
View ArticleReflection of elastic waves
Hello, I am simulating rayleigh surface waves with the structural mechanics module in time domain but cannot get rid of the wave reflections at the boundary next to the surface. I tried of course...
View ArticleGRI Mechanism 3.0
Dear Sir / Madam I need to model two counterflow burners for measuring the NOx formation in case of natural gas combustion. For this purpose I need to upload the entire GRI Mechanism of methane...
View ArticleModel-step index fibre
Hi, I saw a pdf conference, in the Comsol conference 2010 with Anil Prabhaka and his work was about the Engineering Light and in the presentation he shows Model Library was a Tutorial called Step index...
View Articlelive link for matlab does not run the function trapz
Hi: I have a problem running the function trapz in the live link for matlab. Any one familiar with this?. Please help me. thanks, Naema
View ArticleCooling of gas & liquid within pressurized non-rigid tank
Is there a simple setup that can model the deflection of a non-rigid, pressurized, fluid-filled (gas & liquid) tank over time as the fluids cool via external natural convection? Setting the initial...
View ArticleGeneral question about interpretation of boundary condition at interior...
Dear Comsol-community, I am simulating a diffusion equation using the "Coefficient Form PDE" from the mathematics interface in a 2D domain. There is an interior boundary at which I want to set a...
View Articleparametric sweep stops when encountering error
I'm a COMSOL newby and have just gotten into the concept of parametric sweeps. At the moment, I'm running parametric sweeps for fluid flows on a simple rectangular domain. What annoys me, however, is...
View ArticleProblem compiling Java due to model.save command
I want to load my comsol models using java files. I have determined how to create a java file and compile it using comsolcompile. The problem I am having is that at the end of the compiled class file I...
View ArticleExtract mesh connectivity info
Hi everyone I'm trying to find a way to extract the connectivity info of the mesh. Right now I have written a function in matlab that generate that info for me but it is very slow, because my models...
View Articleabout helix geometry modeling
Hi, I am trying to model a spiraling geometry (helix-like) with a complicated cross section. Does anyone know how to do it with comsol 4.2/4.3a? I used the build-in "helix" one but that was with a...
View ArticleThin Thermally Resistive Layer on top of Boundary Heat Source
Hello everybody, I want to simulate a flat mikroheater on top of a foil that is covered by a liquid. Since the foil has a thickness of about 100µm and the liquid covering the heater has a height of...
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