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High index DAE problem
Is it possible to solve high index DAE problems using COMSOL?? I am trying to solve a simple 2nd order differential equation. I see that the profile does not satisfy the initial values given. I have...
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Parametric Sweep for 3 variables
Dear all, I have a stub tuner in my microwave heating system and this tuner has 3 metal stubs (see the attached file) and I would like to optimise the cavity regarding the S11 data by doing a...
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S11-parameter from a 1-Port Microwave Heating Cavity
Dear all, I am trying to model the microwave heating cavity that I am working with (see the attached file for the general view of the system). It's a rectangular waveguide (86x43mm) and only it has one...
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Find temporal location of the maximum of a variable
Hi, I would like to know at which exact time occurs a maximum of a variable, and so far I only got to know the maximum of this variable but not WHEN it occurs. I tried with the operator maxop1 but...
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Empty/incomplete solution-only edges of simulated part get displayed
Dear all, I need urgent help for my current project simulating polymer-bonded magnets. I'm using COMSOL 5.2. So far I generated two modells with different geometries. In my first modell (20x20x1_1.0s)...
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laminr vs turbelent
hello ! my model is PV cell with duct embedded below in order to cool it down . I used laminar conjugate heat transfer ,so the result show good .But depend on Reylond number the flow is turbulent so I...
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Computing capacitance of a sub domain
Hi I've just completed the "computing capacitance" tutorial provided by Comsol here : www.comsol.com/model/computing-capacitance-12689 The model is constituted of a capacitor surrounded by air, and the...
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Electric insulation in electrostatics module
Hi to all I need to use "electric insulation" boundary condition in "electrostatics" module(like that there is in "electric current" module),but there is no such boundary condition in this module! How...
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Undefined variable
Hey All I am new into COMSOL and i hope you guys can help me. I get this message when a try to run the calculation : Undefined variable. - Variable: pA - Geometry: geom1 - Domain: 2 Failed to evaluate...
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fluxes in convection diffusion model
Hey, I'm trying to rebuild the semiconductor diode model from the comsol model library (v. 3.3) with comsol 5.2 and i have a problem concerning calculating the fluxes. I used weak dirichlet bondary...
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Problem when plotting two isotherms
Hello, I am simulating two laser beams in a piece of Aluminum. The beams are separated by a distance of 150 microns with a velocity of 40mm/s. The first beam goes from 0 to 0.5 s, while the second...
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Plane Wave and Excitation in Time Domain Analysis
Hello, I am simulating antenna in RF module and I am facing some difficulties as listed here- 1. I would like to generate a plane wave of THz frequency in time domain which passes through an object....
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Visualising the mesh
Hello, I am looking for some help with visualising the mesh on a certain part of my geometry which is basically a 3D cylinder. I have tried using the mesh plot under 3D plot group in the results...
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Optical Scattering Electric Field Norm
Hi, I am currently attempting to model the optical scattering off a 2D nanoparticle. The background electric field is a plane wave only in the y direction, so I plotted both the electric field norm and...
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Coupling solid mechanics with deformed geometry
Hello, I am trying to create a 2D model where I have (for now) two shapes: a circle and a rectangular plate. Initially, the circle does not touch the plate. What I need it to do is to have the circle...
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Error while calling External C function
Dear users, I'm quite new to Comsol and I'm trying to create a function of time and space which could be later used in my model. Unfortunately I cannot use a Matlab function because my version is too...
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S-Parameters in Microwave Cavity
Is it normal having a -30dB magnitude of S11 in a certain frequency, even if the the Microwave Cavity (Aluminum) is empty? What does it mean exactly? It could be the some parts of the cavity absorbs...
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Heat Transfer in Solids (motion of objects inside a domain)
Hi, I am trying to model a simple 2D transient heat transfer problem. For this I move a sphere with a constant boundary temperature trough a plane making use of the Deformed Mesh and the Heat Transfer...
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PML or SBC
Hi i was working in a 2D microstructured fiber and some doubts become to appear, i hope someone can help me. 1 which one is better to not consider the the reflected waves just the incident in the...
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Material intersection with heating of hollow tube
I have a model which contains a thin hollow tube with two walls. I heat material next to wall #1 and want to simulate thermal expansion deforming that side of the tube into contact with side #2. The...
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