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Volume concentrations in transport of diluted species module

I am confused by the fact that the" transport of diluted species node" in COMSOL only lets me work with surface concentrations. I want to model a 3D problem that has a given volume concentration as...

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problem in inputting signal

i am working on SAW RFID using acoustic module with piezoelectric devices physics and i want to input a signal of type S= Acos(wt+p)rect(t/p) to the input IDT and i dont know how to do it .please help me.

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Pointwise constraint in weak form

Hello, What is the meaning of the value of "Pointwise constraint" in Comsol? It is a strong, bidirectional constraint. If the constraint expression is "-x+1", then is the value of the variable "x"...

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dependent variables: sweep over "initial values" and "variables not solved for"?

Hello all- I have 2 Studies in my 2D model: Study 1 solves for various fields within my geometry. These fields are different for each wavelength (lam0). Study 2 takes the lam0-dependent fields from...

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How to export data on selected points

Hi All I have 1D line plot and I want to export the data of the plot on selected grid points, not the entire plot. Any Idea or suggestion would be of great help. Regards, A.

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Is wave equation automatically included in plasma reactor interface for...

Hello everyone, I am trying to figure out the domain equations taken into consideration for plasma model node in microwave plasma module. If I create only one geometry in my simulation and specify it...

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Piezoelectric Ultrasonic motor

How to couple the piezoelectric generated wave to the slider(object) which is kept in friction contact with substrate? so that the slider will start moving, with force of the Rayleigh wave.

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Silicon onchip Microchannel Water Heat sink

Hi All, I am presently working on a project that involves the simulation of a micro-channel heat sink on COMSOL, i have gone through various literatures and have also followed the microchannel turorial...

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charge density in flow through capacitor

Dear all, I am relatively new to comsol. I am trying to solve a simple 2D flow through capacitor model with electrostatics module, laminar flow having 0.1 M NaCl as the dielectric medium. In the...

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Variable exchange between Matlab and Comsol

Hello everyone, I am running Comsol using the LiveLink with Matlab and am trying to do the following: I have a value, dt, which is 0 everywhere in the beginning. (I can either use dt=0, make an...

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Coupling plate and acoustics

Hi everyone, I'm trying to model a axisymmetric disk in 2D which is actuated with 40kHz in the middle in axial direction which gives a pressure wave in the surrounding air. The air is represented by an...

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How To Create Cross Section In 3D

I have been simulating Mie scattering in 3D by using symmetry so that only 1/4 of my model has to be solved for. The problem I have is that I would like to plot the solutions of the full model with 1/4...

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Different results of Simulation from Solid Mechanics and shell

Hello, I have a problem when doing a simulation with a bend pipe meshed by shell element. The results of principal strains are one time larger than meshed by solid mechanics. But the results of...

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Norton Creep parameters

Hi experts/users, I'm going to simulate creep of polymer by using Norton model in situation which temperature and applied force are constant. I've got question regarding parameters in Norton creep...

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dynamic or static pressure?

For some reason, the question I asked in this forum yesterday was deleted, so I´ll post it again..... Hi, I have a simple "problem" when using the "free and porous media flow" physics. The pressure...

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poroelastic pellicle squeezed at a constant rate: unknown error

Hi I am trying to simulate the squeezing of a poroelastic pellicle under two flat plates at a constant squeezing rate. However, an error comes up and I really don’t understand the reason. The error is...

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Adaptive time stepping scheme for laser pulse train with low duty cycle(1/250)

Hi, I am a new user of COMSOL. I want to simulate the hybrid laser machining process using this software, but the first problem I have to solve is the adaptive time stepping. The duty cycle of the...

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How do I load arbitrary current to the coil in comsol?

In comsol, I want to give the coil arbitrary current defined by interpolation, but it always wrong. My specific approach is: (a) the global definition, using interpolation method defined excitation...

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how to definite infinite thickness layer ????

hello, I simulate dual gratings by RF Module . But I do not know how to dedine infinite layer. I want to set a port as the light source in the top of the module. The material of the first layer is...

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Spherical Indentation

Hi, Im trying to model the indentation of a spherical probe into a nearly incompressible material (Hertzian Contact). The model seems to get a stress concentration at a single point rather than a...

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