What is the exact electric field expression when using the PORTs? -...
Dear all, In the attached 2D model, I use 'Electromagnetic Waves frequency domain' and I would like to study the light propagation inside my structure. I would like to have a input power flow at port 1...
View ArticleVariable exchange between Matlab and Comsol
Hello everyone, I am running Comsol using the LiveLink with Matlab and am trying to do the following: I have a value, dt, which is 0 everywhere in the beginning. (I can either use dt=0, make an...
View ArticleError in compile Equation: Frequency Domain
Hello everybody, I am simulating a microwave devise in optical frequencies but I see this error: Feature: Compile Equations: Frequency Domain (sol1/st1) Error: error in multiphysics compilation I would...
View ArticleCalculating Electrostatic Force without MEMS Module
I've been having difficulty coupling the Electrostatics/Structural Mechanics/Moving Mesh applications. I was previously given advice to look up the MEMS 3D Cantilever Beam model to help me understand...
View Articleimporting txt file to create geometry in comsol 4.0a
hi can i create a geometry by importing coordinate data existing in a text file in comsol4.0a? suppose i am having (x,y) data in a text file and i want to use this data for creating geometry in...
View ArticleVariable change with time
I have a question about variable change with time. I try to make a mass transfer model. The inflow concentration change with time. If t <= 1000s then C=1mol/m^3 else C=0 I upload the data and make a...
View ArticleHow to use interpolation function in parameters?
Dear users, I have defined a piecewise function from a file with function name 'functionName' in Global Variables. I would like to define a parameter that uses this function in Global Definitions ->...
View ArticleStructural Mechanics Equation System
I am trying to understand how my structural mechanics model is computing its solution. The model solves and gives me a reasonable solution. However, I don't understand how it is arriving at its answer....
View ArticleConvergence issue with nano pore electrodeposition model
I am trying to model electrodeposition into a nanopores but am having troubles with convergence. My solution only converges to 1e3 fairly consistently even if I refine the mesh and then it starts to...
View ArticleCFD - Surface roughness
Hey guys I really need your help on this one! I was wondering if any of you could tell me about the default settings of surface roughness's in COMSOL? All I've found about it in the documentation is...
View ArticleWhen I have to use 2d or 3d modeling?
Hi Everybody! I´m Wagner, from Brazil and I have a question, a simple question I think! How I decide if my modeling will be in 2d or in 3d? I have Heat Transfer and AC/DC model and I work calculating...
View ArticleElectromagnetic Induction Tomography simple model
Hi, I am trying to make a very simple 2D model where I have 2 coils in which in between is a medium (air). One of these coils will be excited and have a magnetic field in the direction of the second...
View ArticleHeat Transfer in Fins- Help needed
I am trying to simulate a heat sink, very similar to the one shown in the tutorials... In spite of building a coarse mesh, the solution does'nt converge even after 2 hours of solving. I have an i5...
View ArticleHow can I define nonlinear electric conductivity ?
Hi, I'm currently working on electrical simulation using AC/DC module. How can I define nonlinear electric conductivity of zinc oxide (ZnO) in subdomain settings?
View ArticleProblems with multicore time calculation
Hello everyone, I am working with the attached file and there is a very unusual behavior with the second study. It is a frequency response study with a parametric sweep: I need to know the frequency...
View ArticleCombination of Fluid Flow and Heat Transfer
Hello everyone, I am a new member of this forum and also a fresh user of COMSOL. I hope I will be able to learn from and discuss problems with all of you. My first enquiry to the forum follows: My...
View ArticleCoil inductance and resistance vs frequency
Hi, With the ACDC module of Comsol, I would like to calculate the standard parameters of air coil by taking into account frequency effect (inductance, resistance and capacitance of the coil) I would...
View ArticleSector symmetry on a 1/5 3D electro motor
Hi All, i have a 3D model that shows only 1/5 of whole motor. It has 3 phase and 5 pool pairs. i'm using rotary machinery modul 3D. if i disabled all continuity BC on the outer slice surface, it...
View ArticleHow to use user defined functions as physics's input? Thanks!
Hello, every one! I am learnging to use COMSOL4.2 and want to add AC signal as my device's input. Just as Eric told me to write an equation as the input....
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