How to solve an eigenvalue problem?
Hello, This is my first time to use COMSOL. I want to solve an eigenvalue problem on a geometry : a unit square with a circle inside. I attached file. div ( ep^(-1)* grad u)=lambda * u where ep =1...
View ArticleHow do you create consecutive physics?
Hello all, I'm using two solid mechanics physics, and I would like to study the effect of the second after the effect of the first is already computed. I'm doing this to know whether a second physics...
View ArticlePre stressed frequency domain analysis - How to: Values of Dependent variables
Hello, I am trying to use the solution of the static deformation as the initial conditions for my frequency response analysis. First, I have prepared two solutions, the static deformation is calculated...
View ArticleReaction term
Hi, I'd like to add reaction term just for the certain time in the diffusion model. For example, 0~3 s : no reaction 3~5 s : reaction 5~7 s : no reaction I split studies into three parts (one...
View ArticleSolving PDE on a curved surface
Hello All, I'm trying to figure out whether I can use COMSOL to solve PDE on a curved surface. For example, diffusion of species on a 2D curved domain described by: dC/dt = \Delta_S (C) Here \Delta_S...
View ArticleHow evaluate time when a variable assumes a given value
Hi, It is known that the function "at" evaluates a function for a specific time value. Ex: at(1.5s, u). However, I'm looking for a way to get the instant of time (tx) when a variable (Var) (such as...
View ArticleNLfail despite low tolerances using fully coupled approach
Hi, I try to observe the heating of a system using an electric pulse, i.e. Joule heating (--> Laplace equation and heat equation). The conductivity of the material of interest depends on the local...
View ArticleHow do I set up COMSOL so that the material properties parameters of the...
I'm modeling thermal conductivity as a function of temperature rise due to stimulation. For this, I solved study 1 with user defined thermal conductivity (material properties) and temperature and used...
View ArticleBest Way to Incident Electric Field
I'm currently working on modeling a 2D gradient index metamaterial lens and studying the electric field intensity inside it. My geometry consists of vertical alternating layers of two different...
View ArticleInitial values from solution and user defined for some variable.
Dear all, First I want to thank all the people that contribute to this community, which is very helpful for first hand experience user. I find myself in a situation where there is the need to specify...
View ArticleCan Comsol solve two physics with a common variable together?
Hello I am trying to couple Heat Transfer and Transport of Concentrated Species together. They both have a common variable dependency. I have to put a mass flux in a water-air interface and, the mass...
View ArticleHelp with modeling resistance in current collectors for lithium-ion
Hello, I am not sure if I am in the correct area of this forum for assistance I need. I am currently working on a model for current collectors in lithium-ion batteries. More specifically the voltage...
View ArticleComsol Cluster Computing Problem !
Hi, when i am about to choose three nodes of which are at the settings of comsol cluster, it says "process status" scheduling and it stucks like that. when i am about to choose two nodes, comsol...
View ArticleImpose a limitation for solving an equation
Hi, I'm using general PDE in COMSOL. I want to solve the equation by this condition: The calculated main variable in each time step can not decrease, in other words if A is the main variable, then...
View ArticleTime study simulation
Hi, In time dependent study simulation in COMSOL, we need to define range in study setting as below: range(time1, TIME, time2) This means that the simulation will be study between time1 and time2, the...
View ArticleGeometry building differently during Batch Sweeps than in individual simulations
COMSOL'ers: I have a geometry of a V-antenna which builds properly as a function of angle ("del") when simulated individually; however, when run under a batch sweep (of del) the geometry does not...
View Articleconstraining the range of dependent variables
Hello, I have implemented an axisymmetric drift-diffusion equation using the equation-based modeling interface in COMSOL 4.3 (incorporating the necessary terms due to the curvilinear coordinates). I...
View ArticleHow to set a max and min to the main variable in General form PDE
Hi, I really need somebody help me. How can I set a max and min value to the main variable in General form PDE? Thanks, Arezoo
View ArticleElectrostatic and transport of diluted species coupling to an IPMC sensor model
Dear community, I am trying to build a simulation of an Ionic Polymer Metal Composite (IPMC) strip sensor, a thin membrane of polymer ionic on witch too thin gold electrodes are plated. It is a 2D time...
View ArticleSimulation Based on previous simulation results
I am working on an RF MEMS Switch, I used electromechanics physics and got its results. Now I want to simulate its RF Performance using Electromagnetic Waves, Frequency Domain physics, but based on the...
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