MW Equations + Phase Change in 4.2
Hi, I am using microwave heating option of the RF module for heating a mixture of oil and water.Can any body let me know which set of equations COMSOL is using to solve the microwave heating problem? I...
View ArticleTED in MEMS resonator
Hi I am new to COMSOL. I was trying the Thermoelastic damping in MEMS resonator model [it was done on 3.5 but my version is 4.2a] provided by the comsol. Although I get the similar eigenfrequencies but...
View ArticleCan someone help me understand this error?
I need help understanding the cause of the following error:"Failed to compute elastoplastic strain variables" I have received this error numerous times in a few different structural models where I am...
View ArticleDiode example solved but strange
Hi I tried to solve the semiconductor diode example from the model library but simplifying it a bit. In particular, I discarded the rounded corner and just made it a text book like pn-junction. It...
View Articlestop criterion adaptive mesh refinement
Hi, I have a question concerning the stop criterion of the adaptive mesh refinement (adaptive solver) algorithm: In the Reference Guide stop criterion is only described by: “Terminate execution if it...
View ArticleDifference between "Porous Media and Subsurface Flow" and "Poroelasticity...
I am a little confused by two physical module, the first one is Fluid Flow-----Porous Media and Subsurface Flow, and the second one is Structural Mechanics--------Poroelasticity (Poro). What is the...
View Articletry/catch in matlab for COMSOL
I am doing a parametric sweep in COMSOL with the geometry. The problem is, it is a large parameter space and a few combinations which would be unreasonable to check give an error. It is a stationary...
View Articlehow to model interface position when filling a channel
Hey, I'm quite new to comsol and so my questions are maybe simple to answer - but not for me yet. For my work I try to model a microchannel with 1mm*1mm crossarea and 5cm long, where water is pumped in...
View Articlesolving helmholtz equation
I wish to solve Helmholtz equation for an Axi-symmetric geometry. The problem geometry consists of a excitation source a tube and air box (all rectangles). Is it possible in equation based modeling?....
View ArticleTransient Hot Wire Method
Hi Everyone! I'm new on COMSOL so I don't know too much yet. I need to simulate the transient hot wire method, I don't know how to start with, and I cannot find any example. Could somebody help me with...
View ArticleRegular Meshing
Hi all, I've been asked to create a regular mapped mesh for a cube which has faces of 10 by 10 square areas throughout the whole of the cube. I'm applying a magnetic field to the cube and I wanted to...
View Articledifference in results when the duration of the model was changed
Hi! I ran the same model for a longer time (Rotating Machinery, Laminar Flow module) and the resulting velocity and pressure are different. Which one should I trust? Why does this happen? For the 2 s...
View ArticleHow is the penalty factor used in the penalty method?
I am modeling a transient contact problem using the penalty method instead of the augmented Lagrangian method. How does COMSOL use the penalty factor when the penalty method is being used? I understand...
View ArticleDilute species transport concentration condition
Hi I wonder why the "Concentration" condition in the dilute species transport model is of type "boundary" and not "domain", since its unit is in "Mole/Volume". Why does this make sense? How should this...
View ArticleHow to simulate the dynamic process of the shelled microbubble using COMSOL
We plan to simulate the dynamic process of the shelled microbubble with diameter of 5um and thickness of 10-100nm, which vibrates inside the ultrasound beam with center frequency of 1MHz. There is one...
View ArticleModeling intensity field from high-intensity ultrasound source WITHOUT...
Hi, I cannot afford to buy the Acoustics module, so I'm wondering if it's possible to model the energy being deposited into a material due to multiple ultrasound sources. The KZK equation can be used...
View ArticleHow to define a dispersive material as a function of COMSOL predefined...
Hi: I defined a dispersive material function (frequency dependent relative permittivity) in Global Definition. Function name: LD_real Expression: ff E-14+0.6 Argument: ff Argument unit: Hz Function...
View ArticleAngle of incidence, RF modul, Comsol 4.2a
Dear All, I have issue. I have one metal block on substrate, and I want to illuminate it but at some angle (picture). One half sphere is substrate, one half air. Now I want to apply x polarization,...
View Articlehow to get the average values on parallel channels
Hello everybody. Now I simulate the hydynamics of the distributor with parrallel channels. I want to get the mean velocity values in the middle of each channels. I try to use the 'cut plane' on the...
View ArticleReverse Joule Heating
Hi. This is my first time using Comsol so please bare with me :) I'm doing a model of a HV power cable, that heats up due to the current flowing through it. I know that the temperature of the isolation...
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