Finding a mapping of Current Density (variable J) using the Electrostatics...
Hi everyone, I'm making a model using the Electrostatics Interface from within the limited AC/DC Module included with the base COMSOL Multiphysics package. Initially, I tried making my model using the...
View ArticleMagnetic field
Hello I created a simple model where the magnetic field and electric wire. 1 Why not spread outside the magnetic induction coil? 2 Why is not moving conductor in a magnetic field? What I made a...
View Articlecomputing accurate fluxes with periodic boundary conditions?
Hi everybody, does anyone know if I can compute the fluxes accurately, as described in the user guide on page 308 ff. and file 0973 from the knowdledge database etc, when using periodic boundary...
View ArticleElectrostatics vs Electric Currents Interfaces. Something is wrong...
Hi everyone, I mentioned this in an earlier post. I believe I have an inconsistency with the software (COMSOL Multiphysics Base Package). This may or may not be intended. When picking between the...
View ArticleInvalid Property Value "Lengthunit is a string" Error Message using Livelink...
I have this strange error message when I click on my geometry stating Invalid Property Value - Property: Lengthunit 'length unit' is a string which I cannot get rid of. I think I do not have any length...
View Articlerenew COMSOL license using a passcode
I downloaded the COMSOL 4.3a compact DVD image, double clicked it, then a "COMSOL 4.3a INSTALLER" interface showed. When I clicked the "Change license" button, a window pop out that says "specify an...
View ArticleNon - Isotherma pipe flow
I am not able to find the "Non - Isothermal Pipe flow" module in my COMSOL 4.3a version. Can you help me out how to find it?? If not, I request you to help me with any method for simulating a pipe flow...
View Article3D Poisson equation problem coupled with Nernst-Planck equation
I used coupled Electrostatics physics and Transport of Diluted Species physics to simulate this problem. The source term in Poisson equation is the difference between cations and anions. Usually, the...
View ArticleSubsonic Ramjet Model
I am attempting to optimize the design of a ramjet to be created for rocket experimentation. I have been working on the model for the fall semester attempting to refine it. I am now using a 2d axis...
View ArticleLow Reynolds Turbulent Flow
Hi folks, does anyone know what the "spf.wall_spf" variable means in the AKN Low Reynolds k-ep model. I can see it in the equation view, but other than that, there is no more info... I am really trying...
View Articlebubbly flow: udrift in laminar flow...
Hi, I am currently working with the bubbly flow application mode in a laminar flow. The gaz velocity, ug, is computed thanks: ug=ug+uslip+udrift In the help, is it said that the drift velocity is...
View ArticleTwo interdependent studies - but I cannot use results from frequency domain...
Dear all, How can I use the result from a parametric (parameter 'b') sweep-frequency domain study (e.g. emw.Ez(b) ) in another function defined under Definitions (e.g. f(emw.Ez(b)) ) which is used as...
View ArticleAssigning Materials
While assigning materials to some solids in my model, I am getting a red cross below the material name in Model Builder. What does that mean? What changes should I do to use those materials for the...
View ArticleSimulationtime for mapped meshes in 2D and 3D
Hi, Normally I used triangular meshes to simulate thin films on cantilever beams. Because of the very high aspect ratios I 've tried to use a mapped mesh for the rectangular geometry. The amount of...
View ArticleManipulating data from tables
Hi all, I'm working on a model using piezodevice physics in the frequency domain, and I'm trying to plot admittance in dB (rather than siemen). I've found the admittance by taking the surface integral...
View ArticleALE question
Hi, I'm interested in the transient effects of a moving charged object on a grounded one (see image). I have first modelled this using a parametric sweep on the object's x position. But of course, this...
View ArticleGeneralized alpha time dependent solver
Hi, if I switch from BDF to the generalized alpha time dependent solver the solver works with a timestep of 0 or near zero. I can set a manual time step and the solver calculates the time correctly,...
View ArticleStraw Poll: Who would like to see the model gallery documentation overhauled???
Hello all, I thought I'd post this here to get the community opinions before suggesting it to support. If I want to learn how to use an aspect of Comsol I work through example models and I visit the...
View ArticleUsing step function in kinetic reaction simulation
Hi I am trying to simulate the kinetic reaction of biomolecule interaction in fludic channel expecting to have association and dissociation phase (concentration of complex versus time) in the same...
View ArticleSave the Date - COMSOL Conference 2013 Boston, Oct 9-11
Hello, We are excited to announce that the COMSOL Conference 2013 Boston will be held on October 9-11th. With over 50 events to choose from, including training and presentations, this is the premier...
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