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Error 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...

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How 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 ->...

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Variable 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...

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Structural 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....

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Electromagnetic 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...

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Heat 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...

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Need help with surface differentials

Hi, I have concentration profile in my model, mimicking an electrochemical reaction at a solid-liquid interface, that I am interested in analyzing for total flux towards the surface. My concentration...

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for NdFeB magnet, which constitutive relation is closer to reality

I'm modeling two NdFeB magnets placed very close to each other in a repulsive manner. I need to compute the repelling force between them. There are two options for the constitutive relation. One is B =...

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Convergence 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...

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CFD - 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...

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Sector 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...

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When 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...

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How 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?

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Problems 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...

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Combination 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...

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How 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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Importing a file from AutoCAD to COMSOL

I have created a 3D building model on AutoCAD and wish to import it to COMSOL for CFD analysis. Can I know the process for importing?

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convective heat flux magnitude

Hi , I'm computing heat transfer from a rotating hot sphere in a fluid medium. The flow is creeping type. I have issues related to the various COMSOL options for convective, conductive and total heat...

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Building a mesh having in a thin gap in between two beams

I am using the piezoelectric devices interface (pzd). Some layers are linear elastic and other - piezoelectric. The surrounding block is air and I defined it with the electrical material model. I want...

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