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Overpotential Definition
In the user guide for the electrochemistry branch, overpotential is often defined as the difference between electric and electrolyte potential and the reversible potential, i.e. eta = phi_s - phi_l -...
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Variable used in Solver Configuration - where to define?
To manually set the Maximum Time Step, I would like to link it to the frequency of a boundary frequency. But I cannot use a variable defined in Global Definitions/Variables or in...
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Using Norton Bailey Law: How to determine the Reference stress
Hello all; Can anyone tell me that what does that mean by "Reference stress" in Creep modeling? How to determine it? Usually, Material constant "A" and "m" are used for creep.
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3D AC Coils with Moving Mesh
Hi guys, I'm trying to model a pair of coils, one active with a varying AC current and a parallel passive coil that is suppose to act like a sensor. In this model I'm sending a metallic object through...
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PML width for Longer wavelength
I generally use the wavelength(in case of shorter wavelength)as the starting PML width. This does not create a large geometry to solve, saving some memory. But, my recent models have longer...
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Particle Tracking in AC Fields
Dear COMSOL Community, I would like to track particles in an electric field generated by an AC electrode geometry. I have successfully gotten the particle tracking to work with a DC setup, but find the...
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mass flowrate is non conserved
Dear all, I was trying to simulate the water flow into a system with two inlets and three outlets and I used the ''surface integration'' io order to compute the total mass flow rate and I found that...
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Extruded round edges don't appear smooth
Hi all, I'm a complete COMSOL novice, so I'm probably missing something extremely obvious, however: I am drawing essentially a circle with a rectangle cut out of it to provide a flat edge, and extrude...
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Divide in Comsol
The funniest thing that I have ever seen just happened to me while using Comsol. With all due respect, Comsol gives me a wrong answer for a simple calculation (number from solution/constant number). I...
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How to support flexible tube.
Hi- I am doing a 3D FSI model on a simple branched artery with blood flow. I naturally want the artery to expand and contract as the fluid moves though. What is the best way to constrain the inlets /...
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PML,eigenfrequency analysis
Dear all, I'm new to Comsol sofware. Could someone please tell me if I can use PML in eigenfrequency analysis mode in piezoelectric devices interface of structural mechanics Module. I'm using Comsol...
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Manipulating data in tables
Hi everyone, Such a simple question it seems but I just can't find the answer. How do I manipulate the data in tables? E.g. how to add a column to the table which is abs()^2 of another column? Or how...
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Display results on a different geometry
Hi, I've got the following problem: I'm calculating the temperature and displacement field in an axis-symmetric pressure plate (basically a circular ring) of a clutch system using the "Weak...
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Frequency Dependent Permitivity.
HI Comsol Users I am trying to model the e-filed lines expected for a PbTiO3 crystal with electrodes on top and bottom to which I apply a voltage to the top one and leave the bottom one grounded.. I...
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Thermoelastic damping in MEMS resonators
Dear all, I'm using Comsol to simulate a mems resonator. I want to model thermoelastic damping in the resonator. When I use anisotronic material for my model, I got errors. But when I tried to simulate...
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error during meshing
Hello everyone, Can you please suggest me how to solve intersecting face element error and failed to generate mesh for a particular domain ? This is the error message am getting: Finalized geometry has...
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Coupling problem: Nernst-Planck equation with Poisson not converging
Hi, I am unsuccessfully trying to implement to Poisson equation through the Electrostatic Module into the Module "Transport of Diluted species" for a stationary case. Beside those modules I use the...
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Parametric Sweeping a Geometrical Parameter! Possible?
I have a polymer coil in a solid cylinder. This is a reaction-diffusion model. I think usually the materials property or other similar non-geometrical properties are sweeped in parameter sweep. I want...
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Cannot start up COMSOL 44
Hi, I have installed both COMSOL 43a and COMSOL 44. I used to be able to use both, but suddenly - after rebooting my computer (I work on Linux) - COMSOL 43a starts up fine, but COMSOL 44 has a problem....
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