How to apply ac voltage
Hi all I want to apply ac voltage(using piezoelectric excitation) to an accelerometer to perform transient analysis. I have tried the SPICE circuit editor, but it supplies only dc voltage. Is there any...
View ArticleRayleigh Damping in v4.2
Hi, I'm trying to analyze a cantilever beam and I need to change Rayleigh damping parameters (alpha and beta) but I am not able to find them in Comsol v4.2! I knew how to do it in 3.5! Please advise...
View ArticleTube Heat Exchanger
Dear COMSOL community. I am new in COMSOL and I have some problems with my simulation. Mayby anybody could help me. I try to simulate a heat exchanger. Steam is condensing on the outside. The heat is...
View ArticleHow to export data in excel format?
Hey Ivar, I want to export my figure into excel format. and replot it in matlab. Is it possible ? Thank you very much!! Baofeng
View Article'Turbulent Two Phase Flow, Level Set' Module
Hi, We are designing a two phase (Air and Gas) burner model using 'Turbulent Two Phase Flow, Level Set' module with Transient Initialization. We are not getting any error when we compute the model for...
View ArticleIvar, could you please say something about the solver error?
Hi, I would like to model friction stir welding process. I used general heat transfer module and incompressible navier stokes module together. I do not have any problem with the heat transfer module,...
View ArticleInternal error in geometry composition, Comsol 4.2a
Dear Fellows, I want to make blocks with round edges in 3D. I use standard procedure, I define workplanes, make geometrical objects in 2D, do "extrude", end on the end - INTERSECTION. When I do these...
View ArticleCombustion Flame
Does anyone out there have any experience with combustion modeling? I'm trying to model the combustion of methane and air. Any input would be appreciated.
View ArticleHow to draw a spherical dome?
Hello all, I am very new to Comsol. I am trying to draw a three dimensional spherical dome and mate it with a rectangular box. I have successfully drawn the box with a circular opening on one face. I...
View Articlezero induced current density at conductor boundary, is this normal?
I'm modeling a coil-over-steel-plate system using 2D Perpendicular Induction Currents, Vector Potential mode (emqa), time harmonic analysis (f=1.0 MHz). The calculated induced current density Jz at the...
View ArticlePML and scattering boundary condition in v4.3
HI, Is it necessary to define the outer boundaries of a PML as scattering boundary layers to obtain the losses of a leaky waveguide? In v3.5, I have defined the outer boundaries as perfect electric...
View ArticleHow to have correct expression for stop condition
Dear all, I would like to set the stop condition so when the internal time step below 1e-9, it will stop. I set it as timestep-1e-8, so, so when it is below 1e-8, i will expect it to stop. However,...
View ArticleIntegration with upper bound depending on x
Dear All, I am trying to integrate a function of x in 1D between 0 and x for all x and create a new continuous function, varying with x. It seems the integration coupling (intop) does not have the...
View ArticleComplex eigen frequencies
Hi there I used to solve eigen frequency of a piezoelectric diaphragm with Comsol 3.5 and obtain real values for the eigen frequencies as real numbers. But now that I use version 4.3 for the same...
View ArticleLiveLink matlab, how to plot field distributions?
Hi, I am considering an optical fiber in 2D, where I calculate eigenmodes using the RF module and do a sweep of the wavelength in Matlab using a for loop. Inside the for loop I only have the parameters...
View ArticleBending stresses due to vibration
hi, this is rotor dynamics. A shaft supported by two ball bearings is under vibration due to misalignment of the shaft with the coupling. now i need to calculate the bending stresses in the shaft due...
View ArticleSetting a Constant Temperature on Edge of Cylinder
Hello, I am modeling the flow of a liquid in a pipe, with another liquid being injected and mixing, they are at different temperatures. I imported a Rod I drew in Solid works, I'm injecting a fluid...
View ArticleElasticity Matrix
Hi I have a question regarding material parameter of Si3N4. In the library it is mentioned that "Elasticity Matrix" of Si3N4 is 100 Pa. I just wondered How they calculate this value. Because I need to...
View ArticleWorks on one computer, Damaged or Invalid on another?
I have a 13.8MB ComSol MPH file that opens just fine on my ComSol 4.2a (4.2.1.110) Trial software. However, when I upload it to the internet and download it into our university's Remote Desktop server...
View ArticleInterpolation and parametric sweep
Hi, i have a problem in my project. I use v.4.2 and AC/DC module in frequency domain. I have a model built by some materials, that they depend of the frequency (electrical conductivity, relative...
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