Questions for electric fields in 2D vs. 3D model of capacitor.
Hi guys. I am trying to model a structure, which has a capacitor build into it with SiO2 and air as dielectric. For this I started to model a 2D structure and plotted the electric field as "electric...
View ArticleJoule Heating with Thermal Expansion Simple Setup
Good Afternoon Everyone, I am new to COMSOL but have used other software for simulations (ANSYS), I am currently trying to model an aluminum wire embedded in a polyethylene substrate, just doing a 2D...
View ArticleCantilever MEMS, Eigenfrequency vs Temperature
Hello everybody, I'm trying to simulate the change of the eigenfrequency when the cantilever temperature increases. In theory, when the temperature increases the eigenfrequency decreases. I built a...
View ArticleMagnetorheological Elastomer Issues: Rotation Matrix and Hyperelasticity
Greetings, I am working on a project that uses magnetically active elastomers(MAE) being subjected to external magnetic fields (H). The internal magnetization of the elastomer (M) is oriented in the...
View ArticleHeat transfert / PDE equation
I would like to draw the temperature profile within a sphere cooled outside, whose equation is as follows: diff(T,t) = (k/rho*cp)*diff(diff(T,r)) + (k/rho*cp)*(2/r)*diff(T,r) initial values: t=0 and...
View ArticleFluid-Structure Interaction
Hi, There is a sample Fluid-Structure interaction problem given in Comsol model library. In this module, is it possible to specify the deflection of cantilever in terms of relation between y and x, y...
View ArticleHow to simulate the water boiling by Level-Set method
There is a good example simulating water boiling by phase field. I am trying to use the Level-Set method. However, I was frustrated by many times of failure. My problem is how to deal with the...
View ArticleDealing with Periodic Boundary Conditions, PMLs and interfaces.
Hello, I'm trying to simulate a nanoparticle array over a substrate in order to study its extinction cross-section. To do so I've made a cell with periodic boundary conditions on the sides and two PMLs...
View ArticlePrincipal stress 2d vs 3d
Hi everyone, I have the same model made in 2d and 3d. First and second pricipal stresses are similiar in both models. But third principal stress in 2d are unrealistically high, however in 3d have value...
View ArticleExtracting absorbed power
Hi all! I am currently doing a 2D model where I have an incoming power, and then I have absorption within the material. As a result, I have the value of the intensity everywhere, but I don't know how...
View Articlehi
can anyone explain to me what is geometry linearity and non linearity? what is the different between them? i'm not clear about that... thank you for advanced... :)
View Articlesolving helmholtz equation
I wish to solve Helmholtz equation for an Axi-symmetric geometry. The problem geometry consists of a excitation source a tube and air box (all rectangles). Is it possible in equation based modeling?....
View ArticleTransient Hot Wire Method
Hi Everyone! I'm new on COMSOL so I don't know too much yet. I need to simulate the transient hot wire method, I don't know how to start with, and I cannot find any example. Could somebody help me with...
View ArticleRegular Meshing
Hi all, I've been asked to create a regular mapped mesh for a cube which has faces of 10 by 10 square areas throughout the whole of the cube. I'm applying a magnetic field to the cube and I wanted to...
View ArticleHow is the penalty factor used in the penalty method?
I am modeling a transient contact problem using the penalty method instead of the augmented Lagrangian method. How does COMSOL use the penalty factor when the penalty method is being used? I understand...
View ArticleMagnetic field
Does anybody know how to write this expression on comsol ( ∇/B/^2 )? I meant expression that replace "the gradient of the magnetic field norm square". Thank you
View ArticleFailed to evaluate variable jacobian - using a step function
Hi every one, Im trying to put a BC (volumetric flow rate) in my model as a step function. But the following error occur: Failed to evaluate variable Jacobian. - Variable: step1 - Geometry: 1 - Point:...
View ArticleMax value of a field and its coordinates
Hello, I know that there have been a lot of posts about this topic and I have read many of them but I am still as dumb as before. I need to find the value of the maximum value of the field in a domain...
View ArticleUse contour plots as geometric entities
I saw in the release highlight video that in v4.3a that you can use contour plots as geometric entities. How do you do this?
View Articlestart comsol server on cluster on multiple compute nodes
Dear, I would like to run the comsol server on multiple nodes, with each 8 cores, on a linux cluster. For this I use the following command in a PBS script: comsol -nn 1 -np 8 -f ${PBS_NODEFILE} server...
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