Sensor Positioning
Hello all, Can anyone give me a hint on how to use vibration as an indicator to find the best positions of sensors on a simple geometry? Please someone help, i need urgent help :(
View ArticleInitial value-Initial guess at a time dependent solver
Hi all, I was wondering whether Comsol is using an initial guess for every time step at the time dependent problems. I know that it needs an initial value (at time=0) to start solving the problem. My...
View ArticleRadio wave antenna calculation, solution doesn't converge
Hi, I was trying to study the radiation from an nano-scale antenna as well as its impedance. However, the solution doesn't converge. I tried all iterative methods, unfortunately, none of those actually...
View ArticleVariable WAr in microwave plasma simualtion & other
Hi everyone, I'm trying to re-do all the steps of the following model : inplane_microwave_plasma.mph, available in the model library. I encountered two different problems that i don't understand. 1)...
View ArticleTutrial help
Hello, I am having trouble doing the stress analysis of a rotating disc with some angular velocity, varying density and varying thickness.Please help me to solve this problem urgently.If possible...
View Articleweak magnetic field converges, strong magnetic field does not converge
The simulation should analyse the following problem: A magnet is passing by a piece of iron. (sketch.jpg) As Study Step I chose Time Dependent. At first I tried a simple problem, where the magnet was...
View ArticleTracing a single particle in an expending pipe in a fluid
I would like to module an finite pipe inside a fluid that expands in time and the effect this expansion has on a near by particle. In the attached illustration, the wired tube is the pipe, and the blow...
View ArticleElectric field distribution - Point Source
I want to simulate the Vertical and Horizontal polarization of dipole source. Its Au-GaAs-Air structure with electric dipole source. You can find that in attachment. For this we need to import n and k...
View ArticleA SMALL DOUBT ON PORT POWER VALUE !
Hi all, I am new to this software and I am trying to simulate a multi-layer structure on which plane electromagnetic wave is allowed to fall at normal incidence. I kept the port power at the default...
View ArticleEigenvalue problem with Dirichlet Boundary condition
Hi all, I am a newbie of comsol and try to solve eigenvalue problem in a finite region using the PDE module. When I try to impose Dirichlet boundary condition, it seems not working. The...
View ArticleElectrical Circuit, Pulse source
Hello Comsol users, I want to model a simple electrical network. But the voltage source is modeled as a pulse source. And I have big problems with the solver. Any idea how the solver has to be set? I...
View ArticleMissing Voltage
Hello all, I seem to be having a problem with the electric currents model. I have a boundary current source defined for an object in a poorly conductive medium. Over the domain of the object the...
View ArticleInitial conditions (problem) - Fluid Structure Interaction
Hello, I am working with the FSI module and I am trying to simulate the pumping phenomena in a micropump, by means of a moving plate. I have successfully obtained results for certain design parameters...
View Articlejacobian error
Hi all, I am running more than one model in the same file, separately. I do it because in one model I need the results of another model. I tried to refer to a solution typing, for example mod1.mf.Bx....
View Article1D Schrodinger equation
Dear Comsol users, I want to solve radial Schrodinger equation for Hydrogen atom in comsol. So I use 1D axisymmetric coefficient form PDE and solve for eigenvalues with boundary conditions as u =0for...
View Articleglobal equations (ODE) and global variables
Hi, I'm trying to define an equation in global equations and it is corresponded with the coordinates x and y (or certain global variable), e.g.: States Name (u) Equation f(u,ut,utt,t) Init (u) u u-rho...
View ArticleVariable modifications between solution iterations
I'm developing a transient model using the Livelink interface. The model first calculates an initial solution for the first time window, then I would like to modify the state variable values due to...
View Articlefrequency domain using reduced basis (modal)
Hi all, I'm trying to make a frequency sweep on a (big) model of an acoustic cavity, with specified surface impedance as boundary conditions. If I use the "Frequency domain" study, everything goes...
View Articleacoustic pressure, frequency response on modal basis
Hi all, I am using Comsol 4.3a and I can't find what's wrong with my use of the frequency response study using reduced model. This is my second post on the subject, as the first one didn't attract much...
View ArticleRe: maximum (or minimum) value in a time domain
Hi To tr to obtain starch gelatinisation after cooking and cooling, I tried to use what describe at www.comsol.com/community/forums/general/thread/28107/ I did not succeed. Perhaps I did not find the...
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