Initial condition for time dependent study
Hi, I'm trying to model free vibration of a small PZT cantilever (MEMS). I need to apply some initial conditions on displacement in a time dependent study. How can i do it? Thanks Andrea
View ArticleUsing external file data for heat source
Hi all, I am trying to solve a model for heat transfer in solids using external data as heat source input. The geometric model is simple and composed of 3 separated bodies attached together by a...
View ArticleFailed to evaluate variable: freq
Hi COMSOL Users, I'm new to using the v4.x series of COMSOL, so perhaps I've missed something simple, but I get an error when trying to plot body volume force variables. The error message...
View ArticleTest function for Electric field
Hey all I am working in the 2D piezoelectric module and I want to take weak forms of Electric field in different direction, test(pzd.EX) and test(pzd.EY) but its showing error. When I try by making the...
View Articleflow boundary conditions: periodic velocity fall and normal velocity zero
Hello, I am attempting to simulate a 2D flow of a suspension of solid disks on a square lattice. To reduce the computational expense of this simulation, I'd like to consider shear on a single disk at...
View Articletime dependent coupled thermal structural with slow & fast pressure & thermal...
I ran a time dependent coupled thermal-structural problem with temperature dependent structural and thermal properties. When the thermal and pressure pulses were ramped up over two seconds no problem....
View ArticleCurrent Source and violation of Maxwell-Ampère’s law
Hi, I have setup a model using both Electric Currents and distributed ODE and PDE interfaces using a simple 2D square geometry. One boundary of the geometry is set as ground and another used to apply...
View Articleheat transfer module
hi, I am new for COMSOL multiphysics.. i was modeled a breast with its properties can we apply heat to the tissue for certain period of time?can you help me how to do it?
View ArticleQuestion about using multiple processors in Gui mode for "form union" operation
Hi, I am currently working in the RF module on a cluster. Right now, I'm working with a very large geometry (large in that it contains many domains). It is so large that it takes a very long time for...
View ArticleCalculating advective/diffusive fluid flux over a boundary -darcy's law and...
Hello, Currently, I am modeling the transport of diluted species under concentration gradient and pressure differential in the soil which enters the building through foundation cracks. I am using two...
View ArticleRF module, why cannot I get expected beam of light
Hi I am trying to get a beam of light. I tried the expression “Ex=exp(-(x^2+y^2)/w0^2)*exp(-j*emw.k0*z)” when solving for scattered field instead of full field. I right clicked “solver...
View ArticleCompatibilty
I am using COMSOL 4.1 RF Module. When I try to open a file older than version 3.5 I got error message. Is there a way to open those files? I think I should be able to open them since the later versions...
View ArticleTransmission spectrum for optical waveguide
Hello, I am currently trying to extract a transmission spectrum from a Si waveguide on top of SiO2 substrate. There are some gold particles on top of the Si (this configuration is taken from an article...
View ArticleHow to set different thermal conductivity in different direction?
I am trying to simulate a heat transfer model which includes layers with different thermal conductivity in X-Y direction and Z direction. Is it possible to assign a user defined material and have...
View Articlesinusoidal function
Dear all I have to use a sinusoidal function [e,g X0+(X1*(cos*(w*t)))]. Where and how can I write it? rgds Anup
View ArticleNegative port impedance
Hi All, I am currently doing some antenna modeling. The antenna is excited by a 50 Ohm coaxial port. I get reasonable S11 results at resonance but the lumped port impedance is negative e.g. -5 Ohms....
View Articlehow to create polar plot in journal bearing
hello, need some help from u all to plot these polar plot. these study about pressure distribution around bearing surface of hydrodynamic journal bearing.. radius bearing : 50mm height bearing : 50mm...
View ArticlePersonalized heat source
Good morning everybody, I am a novice in use of COMSOL, I want to simulate the propagation of heat through a material, sounds easy but my heat source is a surface defined by a matrix (every pixel is a...
View Articleexport animation
I try to export an animation to file. Comsol 4.3a displays the animation and takes time for the writing process but the file is not actually written. What could I do wrong?
View ArticleTime dependent study convergence
Hi, I am trying to model laminar fluid flow, heat transfer in fluids, and mass diffusion simultaneously in comsol using transient solver. The problem is that when I put the upper limit for time 1...
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