PML width for Longer wavelength
I generally use the wavelength(in case of shorter wavelength)as the starting PML width. This does not create a large geometry to solve, saving some memory. But, my recent models have longer...
View ArticleParticle Tracking in AC Fields
Dear COMSOL Community, I would like to track particles in an electric field generated by an AC electrode geometry. I have successfully gotten the particle tracking to work with a DC setup, but find the...
View ArticleCoupling：How to couple Laminar two-phase flow with electroosmotic
Hello,everyone. I‘m trying to simulate a microfluidic chip using electroosmotic pump.Because I want to capture the result that water erupt off the chip into the air,so i introduce the physics— Laminar...
View Articlemass flowrate is non conserved
Dear all, I was trying to simulate the water flow into a system with two inlets and three outlets and I used the ''surface integration'' io order to compute the total mass flow rate and I found that...
View ArticleExtruded round edges don't appear smooth
Hi all, I'm a complete COMSOL novice, so I'm probably missing something extremely obvious, however: I am drawing essentially a circle with a rectangle cut out of it to provide a flat edge, and extrude...
View ArticleHow to support flexible tube.
Hi- I am doing a 3D FSI model on a simple branched artery with blood flow. I naturally want the artery to expand and contract as the fluid moves though. What is the best way to constrain the inlets /...
View ArticleDivide in Comsol
The funniest thing that I have ever seen just happened to me while using Comsol. With all due respect, Comsol gives me a wrong answer for a simple calculation (number from solution/constant number). I...
View ArticlePiezoelectric MEMS Energy Harvester
Hi, I'm using COMSOL MEMS Module and trying to compute eigen frequency and frequency response of the MEMS energy harvester design. My design have non-linear cantilever clamped at both ends and proof...
View ArticleQuad Meshing
Hi, Can somebody teach me how to do quad meshing on the attached model? I tried to use mapping but since there are boundaries which are bounded by only 3 edges, making mapping not applicable at all...
View Article2D-Axisymmetry not considered for domain probes in the calculation "Average"...
Is the 2D-axisymmetry not considered in the calculation of domain probes? I learned, that I had to check the checkbox "Compute Integral in revolved geometry" when I wanted to calculate the correct...
View ArticleHow to coupling Pressure Acoustic, Frequency Domain(acsl) and Solid Mechanics...
hello, everyone I want to simulate a vibrating membrane to measure the output sound pressure in the air. I want to use Pressure Acoustic, Frequency Domain(acsl) and Solid Mechanics (solid) Physics,...
View ArticlePDE module-changing the dependent variable
I am using the PDE module of Comsol. Does anybody know how I can force the dependent variables to stay positive? (e.g. I am solving a PDE for Y and I want Comsol to change the sign of Y when it becomes...
View ArticleBimetal nanocylinder 2D simulation
I am trying to model the local electric field enhancment given in figure 6 (Ag sphere) of this comsol paper (attached). I am getting a peak for local field enhancement. However, I am getting a very...
View ArticleExtract data function with Matlab?
Hello everyone, I have a problem under Comsol with Matlab and i am sure it should be quiet easy to solve. My model: it´s a simple box (square with a=20km) with a very thin crack in the middle define as...
View ArticleConvergence problem with system of pde's: compressible flow + pde for density
Hi, Here is the problem: I am solving these equations having a periodic boundary conditions in a square. At the top and bottom of the square the constant velocity v0 and pressure p0 is applied. It is a...
View ArticleComsol 3.5 error 9040
Hi, I have comsol version (3.5) for Mac OS X and I have this error message: Error: 9040 Fatal error. - Type: NoClassDefFoundError what should I do? Thank you.
View Articleboundary condition inconsistency
Hello all, does anybody know how to avoid a boundary condition inconsistency on an edge where a no slip condition (u=0) meets a moving wall boundary condition (u=velocity) Thanks and regards Sabine
View ArticlePhoto carrier generation in the Semiconductor Module
I'm trying to figure out how to achieve photo-carrier generation in a direct band gap semiconductor in the COMSOL 4.4 semiconductor module. The only form of generation I see in the module is Impact...
View ArticlePDE solve eigenfrequency
Hi everyone. I am trying to solve a eigenfrequency problem with PDE model. The structure in my model is very simple(a square and a circle in it),the material of it is elastic . Of course the Structural...
View ArticleAbout Material parameters
hi everyone I want to know the property of piezoelectric materials(such as elasticity matrix, coupling matrix and so on ) used in comsol come from which references? Is there anyone know it, please tell...
View Article