Solve PDE on 1D domain?
Hy guys, I have a problem with solving a PDE based model defined by me, it is not a default template in COMSOL. My problem is that the equation is solved for the time domain, but not for the geometry...
View ArticleConvergence error using batch command line
Hello, I want to solve a single phase fluid flow, turbulent low Reynolds k-epsilon model in batch mode. This works fine when trying to run from the COMSOL desktop (i.e. with GUI). However when I try to...
View ArticleHow to combine the Frequency Domain and Coil Current Calculation
Hello everyone, i´m trying to simulate an numerical coil with alternating current. The coil is built with the "Multi-Turn Coil Domain". My coil type is numeric wich requires an additional "Coil Current...
View ArticleCOMSOL in parallel mode: a speedup of 20% using 4 cores?
Hello everyone, I have performed the following experiment. Using the command -np #cores, I have forced COMSOL Multiphysics to use 1, 2, 4 or 8 of the available cores on my computer. I also used the...
View ArticleStep Function as BC
I want to implement a change in the velocity/flow in a laminar flow problem. I added the step function (tag: step1) but I am wondering what the correct syntax is when adding this in the velocity...
View ArticleConvergence: when should I stop the model?
Hi everyone I have been working on models that take several days to solve. One of them is running at the moment, and I just have a general question. When I look at the Convergence Plot 2, which is...
View ArticleVelocity gradient expression in 2D-axisymmetric
Hello, the velocity gradient tensor for a 2D-axisymmetric problem presents, for the phiphi component, the following expression chns.graduDGphiphi = if(abs(r)<0.0010*h,d(u,r),u/r) does anyone know...
View ArticleHow can I export an eps image (vector graphics)?
Hello, I would like to export an image of the model geometry as an .eps file (vector graphics). I could not find how to do that and it seems that the only options are jpg, png and bmp. Thank you.
View ArticleSurface evaporation, condensation
Hi, I want to model surface evaporation from a water flow at 40 Celsius and observe the consequent condensation on a cold surface. Can you help me with the model that I should use? I could not find...
View ArticleNew "Introduction to COMSOL Multiphysics" book now available
Hello, We are pleased to announce that a new version of the "Introduction to COMSOL Multiphysics" book is now available for immediate download...
View ArticleApparent inconsistency in induction heating solution methods
Hi everyone, I'm new to COMSOL 4.3, and I'm trying to properly use the induction heating module. While modeling the problem of a current loop heating several iron inductors embedded in water in 3D,...
View ArticleHow do I do a plot of total plate stress against frequency?
I have a shell plate being driven by a point load and I already have surface stress plots that show stress at particular frequencies. What I'd like to do now is do a line graph showing total plate...
View Articlehow can I use plasticity model in the poroelasticity module
I want to use soil plasticity model in the poroelasticity module? How can I add soil plasticity model into the poroelasticity module? I notice I can add soil plasticity model in the structural...
View ArticleTutorial required
Hi, Does any one have a tutorial on coupling 3D SM module with 3D shell with continuity of displacement boundary condition at the interface???. How can it be done in Comsol 3.5(a). Kindest regards
View ArticleHelp understanding detailed solver log and time-step size selection
Hello Everyone, Could someone please help me understand what is happening in this excerpt from one of my solver logs? I'm trying to understand what exactly the non-linear solver is 'thinking' so that I...
View ArticleIs the Comsol Model Class a Handle Class in Matlab? Can/should I pass it as...
Hey there, I'm new to Comsol and I'm developing my first Matlab application using LiveLink. As I understand the object oriented concept in Matlab, there are two types of classes. Value Classes and...
View Articleunable to rectify the syntax error in expression
sir,i have neen trying the example problem Electroosmotic Flow in Porous Media Model ID: 11 after computing it says syntax error in expression. . .i could not rectify it. . so please give me a solution...
View ArticleSpinning Disk Trick
Hello guys! My name is Domien and I'm new here :) I'm a physics student at the University of Antwerp, Belgium. I'm currently working on my Bachelor's thesis. I'm trying to model a Spinning Disk with a...
View Articleelectroosmotic flow in porous media. . . .pls friends respond me. . . .i am...
it says expression syntax error while computing. . . plz work it out and help me how to rectify it. . . .its an example problem. . . .just type electroosmotic flow ih documentation help. . .u will find...
View Articleold model cannot be reconstructed....
I am attempting to build on a model using Darcy's law to model solute transport under saturated conditions. The original model was built in COMSOL 3.5a, and I get an error message "Old model cannot be...
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