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Find a typo from the software documentation
COMSOL engineers, This is an obvious typo from the documentation from 5.0 version COMSOL_ReferenceManual.pdf Page 634 The No Flux equation is exactly the same one as the Page 635 Flux one. I guess the...
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Refractive index of ITO coating
Hello everyone.. I want to simulate a periodic structure which contain ITO coating and it is sandwiched between dielectric and metal. I want to calculate the spectrum of transmission, but for this i...
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How to get the derivative of stress along r direction in 2-D axisymmetric model
I found if I use 'd(solid.pm,r)' to calculate the derivative of pressure along the r direction, the result is very weird, like the Figure 1. However, the 'd(solid.pm,z)' can give me the right...
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Access Model Temperature Values? - COMSOL 5.0
I am running COMSOL 5.0, and I would like to define a Global Variable for ionic conductivity (IC) within my new material. This has a function of the form: IC = 40.25*exp(-1000/T) Unfortunately, COMSOL...
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Why the generated voltage is negative? (in a piezoelectric pressure sensor,...
Hi, I am using frequency domain study to analyse a piezo sensor. But it is so strange that in some frequencies the generated voltage is negative, while in other frequencies it is positive. I do not...
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Find another typo in Software Document
COMSOL Engineers, Find another typo here in SemiconductorModuleUsersGuide.pdf Version 5.0 Page 25, the equation of the Debye Length is wrong, the unit does not match up! k_B T / q has unit of volt...
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solid deformation and heat transfer
First off before I ask my question is state that I have gone through the forums and the book in great depth and have not been able to figure this out. I'm using version 4.3 and do not have the solid...
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resonance frequency
I have built a 3d-rectangular cantilever structure .base is aluminium with dimension 100*30*4(micrometer)and piezoelectric material is aluminium nitride with dimension 100*30*2. I followed the...
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2d & 3d results mismatching
hello sir, i am designing the resonator structure using piezoelectric module. i designed the device and plotted all required results but my problem is that i designed the devise in both 2d and 3d model...
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Computation takes too long for solving even with coarse and normal mesh
Hiii, I have a simple geometry and I want to find the inductance and the resistance of the same. However, I do not understand why the computation takes so long for this. I wasnt able to compute fully...
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high-end computer-guidance garbage
A couple weeks ago we asked for some guidance from COMSOL on a computer upgrade - for running big problems - 10 to 20M DOFs. We were directed to this pagewww.comsol.com/support/knowledgebase/866/ where...
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solar cell simulation
hi... i am new in comsol. Can anyone help me to simulate a simple solar cell? I want to plot the I-V characteristic curve and evaluate the efficiency of the cell.
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Simulating a solid cylinder with a transient displacement point source to get...
Hello, I have been trying to simulate a cylindrical model using structural mechanics(time dependent) with a transient displacement point source (0.00005*sin(2*3.14*3000*t)*e^(-((t-t0)^2)/(2*(sigma^2)))...
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Error evaluating variable
Hello, I am trying to model a heat transfer and mass diffusion process using the PDE module using the coefficient form and general form as function of "C" concentration and "T" temperature. However,...
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meshing metals intelligently in rf problems
From what I’ve been able to figure out, COMSOL doesn’t really know how to mesh bulk metals (where the minimum dimensions are much greater than the rf skin depth) intelligently. There is no rf field...
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How to draw a periodic waveguide?
Hi all, I have a simple question towards for geometry for which I didn't a lot of search but still confused. So how do you draw a periodic waveguide that has a simple mathematical expression in 3D? For...
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Modelling a Quantum Cascade Laser via Copper Heat Sink and GaAs
Apologies for the long post. The model is attached in the attachments. A simple drawing of what I am trying to model is shown in attachment (1). I am trying to simulate a type of Quantum Cascade Laser,...
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How can I ensure Discrete locations for ions in a nanoscale ion-transport...
I'm using the Transport of dilute species module, and have coupled this with the Poission-Boltzmann equation (with Steric accomodations) to model transport of Sodium ions and Cholride ions in a...
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Data Analysis in COMSOL
Hi all, I am simulating an electromagnet, but my question can be extended to any other problem. Is I want to know the field average, the max and min value along a cenrtain axis I can define a cutline...
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Joule Heating and Thermal Expansion
Hello, I'm trying to solve the problem of Joule Heating and Thermal Expansion by applying current via terminal. Somehow I'm getting the following error."Failed to find a solution. Singular matrix....
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