Local derivatives on an edge
Hello Community, I'm building a 3D model in which edges are randomly oriented. On these edges I'm trying to implement a weak formulation of a pde but I can't figure out how to compute the derivatives...
View ArticleERROR: FAILED TO EVALUATE VARIABLE JACOBIAN, Variable: Freq
Hi, I am getting the following error: Failed to evaluate variable Jacobian. - Variable: freq - Geometry: 1 - Domain: 1 2 3 - Feature: Stationary Solver 2 (sol2/s2); - Error: Failed to evaluate variable...
View ArticleGeometry visualization
Hi all, I have a comlex geometry in 3D, which is not suitable for simplification. I have to model a wire of a coil together witz its insulation. The wire has a dimension of some mm while the insulation...
View ArticleProblems with postprocessing in particle tracing
I ran some simulations in the 4.2 version of COMSOL using fluids mechanics the particle tracing postprocessing module. When we updated to the 4.3a version, we began having problems visualizing the...
View ArticleComsol With matlab: non monotonous interpolation grid
Hello all, Im using Comsol 4.3 with matlab. I use the transient time solver. Anytime I set the solver for short time stepping < 1e-4 seconds the calculation crashes and I get the following error: "...
View ArticleElectrostatic Actuation with COMSOL Multiphysics
Hi, I am looking for this webinar from 2011 Electrostatic Actuation with COMSOL Multiphysics promoted by IEEE / comsol (spectrum.ieee.org/webinar/1927822) Any idea where I can find a copy? Thanks for help
View ArticleCan you import data into Comsol 3.5?
Hi, I'd like to import data into Comsol 3.5, for example, the refractive index of a material. The data are in such a format: wavelength(nm) , n 300 , 2.5 301 , 2.49 302 , 2.48 303 , 2.47 etc. I'd like...
View ArticleOne way multiphysics coupling within a transient simulation
Hello Fellow Users, I am solving two physics (fluid flow & species transport) in a transient simulation. The fluid flow is not affected by the concentration distribution. As of now, i have...
View ArticleDiffraction Pattern
Hello, This is probably a very simple question. In the diffraction patterns example in the model library, how can I extract the amplitudes (or the intensity)? Many thanks Hamid
View ArticleTransient contact model
Dear, I would like to use contact pairs in a transient model. In the COMSOL manual I read that you cannot use contact pairs together with the transient solver. An alternative is to use the parametric...
View ArticleThermal contact resistance
Hello, I'm trying to model a thermal sensor in contact with a solid. To do this, I need to embed a heat source in one material and then see the heat flow into a second material. I also need to account...
View Articlecalculating fundamental mode index by wavelength sweep (PCF)
I am simulating photonic crystal fibre (PCF) structures in comsol 3.5a and I want to calculate the solutions (effective index) by sweeping the operating wavelength. is anyone here know how to do that....
View ArticleDefine Young's Modulus as a piecewise function dependent on strain
I'd like to define a new material with a nonlinear Young's modulus as a piecewise function dependent on strain. I've defined the piecewise function under Global Definitions, but I'm confused as to what...
View ArticleMie scattering in 4.3
Hello, I have already seen some discussion about mid scattering of a gold nanosphere. But I the discussions I have consulted, no one has yet implemented a mie scattering program in Comsol 4.2 or 4.3...
View Articlehow to measure max and min electric field of certain surface area ?
I simulated the insulation with a void , ( rectangular and circle) in 2D. any way I want measure the max and min of electric field on the surface of the circle (certain surface) then how can I do THIS?...
View ArticlePlot an expression along a specific coordinate system
Hi I defined a cylindrical system (r,phi,a) and I'd like to get the results along one of these specific coordinates. Since all the direct results expressions are defined in cartesian coordinates...
View ArticleHow to set properties for material.
I simulated the insulator model in 2D-axial symmetric in AC/DC Module. i use com sol 4.3. i have some doubts related to that. How to set (or) apply a switch threshold value for particular (my model)...
View ArticleFailed to generate mesh for subdomain
Hello everyone, I have a metal nanoparticle (radius = 100nm) next to an emitter embedded in glass ( n = 1.5). The computational domain around the metal nanoparticle and the emitter is also spherical...
View ArticleApproximation curve by an exponential
Hello, I would like to know if it's possible to approximate a curve by an exponential one determine and plot it on Comsol. Thks
View ArticleFrequency Domain Calculation regarding a thin steel plate with piezos
Hello, I did some eigenfrequency simulations regarding a thin steel plate with two piezos attached. (PiezoA and PiezoDUT) I placed the piezos at the maximums of a mode shape at about 122Hz. For the...
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