pointwise constraints
I am wondering if someone can explain what pointwise constraints are. When should I use them? The most important thing I want to know is, what does it mean to use pointwise constraints with an equation...
View Articledirac delta function
Hi, I am beginner in comsol and I am trying to solve a problem with a dirac delta function at the boundary domain. I am dealing with a bidimensional convection diffusion problem, with a source in x = 0...
View ArticleRigid connector as rotation sensor
Hello, I'm trying to use the rigid connector as an angle sensor, but I'm having troubles interpreting the values. In my case I have a 3D solid mechanics simulation of an object, and I apply a rigid...
View ArticleFloppy disk magnetostatic simulation at high fields not matching empirical...
Hello, I'm running a 3D magnetostatic simulation that models portions of floppy disk material stacked up to create regions of different thicknesses (geometry screenshot attached). This is being used as...
View ArticleMirror temperature field on x,y-plane (General extrusion coupling)
Hello, I would like to simulate a stationary heat transfer problem in a first step and the Eigenmodes (with the pressure acoustics modul) in a second step. Because the heat transfer problem is...
View ArticleUse LiveLink for Excel with Excel Solver
How can I use the Solver in Excel to fit some parameters of a Comsol model like "Heat conduction in a finite slab" #250 in the Model gallery ? Pressing manually the Update & Compute buttons for...
View ArticleSuperconductor in external magnetic field
Hello I'm new to COMSOL. I'd like to simulate type II superconductors in an external field. I could not find any examples in the comsol documentation. Maybe one of the experts has already done...
View ArticleVariable names in error messages: How to interprete the name of a variable...
I got an error message:" The source selection for the operator root.comp1.solid.cnt1.max_dst must be nonempty.Error in multiphysics compilation." How can I interpret this message? How can I know,...
View ArticleTransfering comsol solutions to another grid system
Dear all, I am simulating fiber modes using COMSOL in conjunction with MATLAB. After simulating the modes, I extract the modes (Ex,Ey,Ez,Hx,Hy,Hz) with the intent to calculate the overlap between the...
View ArticleMeshing Issues
Dear all, Can you please suggest good meshing for the model attached. As i tried with different approaches but model didn't work (I cleared all mesh and solutions for ease of uploading ) Thanks --...
View Articlemesh problem
Hi I am using Comsol, heat transfer module. My geometry has a thin layer inside a box. I used swept mesh for thin part however for all box I used Tetrahedral. But when building mesh I got the error of...
View ArticleComplex Band Strucutre - Acoustics/Structural Mechanics
Hi In a typical phononic band structure calculation done within COMSOL the procedure is to define Floquet BC's and do a parametric sweep of the wave vector over a particular direction in the...
View Article3D MEMS resonator based on a disk
Hello everybody, I am trying to simulate in a STATIONARY simulation a quarter of a disk which should resonate being clamped to to points which are at the end of bars couplers. Even when I am changing...
View ArticleCombining a 3D magnetic field with a 2D fluid flow
Hello, I have a 3 dimensional array of magnets that creates a complex 3D magnetic field. I would like to take a 2D slice of this magnetic field and apply it to a 2D fluid flow. Is this possible, and if...
View Article3D Electric Double Layer Problem
Hello, I am trying to simulate a 3D EDL in a nano channel tube. I set artificial conditions: negative surface charge density to the tube surface, no flow condition ( dP=0, dV=0) for the inlet and...
View ArticleMaximum of point probe over time during solution
Hello, I'm running a large batch of time-dependent models. The simulation time should change for each model depending on the parameters I input, so right now I'm using a really long solution time and a...
View Articlemoving a particle through the laminar flow
Hi I want to simulate the problem in which a sphere moves through a fluid and study its time dependent profile but I can't move the sphere anyway. I used the moving boundary condition for particle...
View ArticlePiezoelectric sensor
Hi I am new to COMSOL and I am trying to use Piezoelectric module in Structural mechanics for sensing. So on input displacement there is an output voltage. I am not sure how to proceed. If someone can...
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 ArticleNonconvergence of time dependent solver using dynamic compression equation
I am trying to implement dynamic compression to a 2D model using triphasic theory of cartilage, but I always get a singularity problem. The nonlinear solver is nonconvergent in the first time step of...
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