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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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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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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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LiveLink

Dear sir, Is there a LiveLink extension in COMSOL 3.4 version for importing files from AutoCAD to COMSOL?? Please help me out how to find it in my installation?? Thank You...

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solvers in 4.3a/4.3 version

Hello I am interested in accesing solver information for ODE/PDE in Comsol. So far I was using the Matlab - COMSOL connection in 3.5 version which was showing a sequence like: fem.sol=femtime(fem, ......

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2D Model Problem...

Hi all, I'm working on a model which is a 2D representation of a solid container in a multiphase-flow section. what I'm trying to model is to study the relation between the contact angle and the ratio...

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Problem: Oil Droplets Seem To Dissolve In Water (Two-Phase Flow, Level Set)

I have a problem with my "Two-Phase Flow, Level Set" simulation in COMSOL 4.2. I am trying to simulate the formation of oil droplets in water by hydrodynamic flow focusing. The water and oil are...

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Surface Integration with different modes

Hi all, I have calculated the results for the different transverse modes in an optical waveguide using the Mode Analysis solver in the RF module. Now I want to perform a surface integration across one...

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Structure with 2D and a 1D truss...

Hello all, I am trying to implement this (see attachment). I guess it should be relatively easy, and for sure lots of people know how to do it :). After "spending" quite a lot of time, I decide to...

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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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Unexpected results with "Ground" BC

Hello, I do most of my modelling using electrostatics steady-state solutions. One thing that comes up in my models alot is a grounded metal object in a linear, vertical electric field as shown in the...

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Two 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...

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Radiation in conjugate heat transfer

Hello all, I have the CFD module and am using conjugate heat transfer. This means that I don't have surface to surface radiation but I do however have surface to ambient radiation. I am modelling...

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Diamond Young's Modolus Property confusion

Hi Comsol Community, the Young's modulus property of diamond in the Comsol material library is 105 x 10^9 Pascal whereas the proper property value in literature is an order of magnitude larger: 1220 x...

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