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modeling of Diffusion

Hi, I want to model a simple mass diffusion process, but with a concentration dependent diffusion coefficient. In variable I defined a function for diffusion coefficient. but when I want to solve the...

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Meshing problem for coaxial cable with helical inner conductor

Hi Good day. I am using a coaxial geometry which has helical inner conductor and cylindrical outer conductor. I am also using emw physics.while simulating/mesh generating I am getting error which...

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vertical exaggeration

Hi all, I'm trying to change the views of my 2D plot in order to have a vertical exaggeration (1:4). I've tried to play with the lock aspect ratio but it seems the model is squeezed into a cube-like...

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Prescribe number of Meshing Elements

Good day, for a model of simple geometry (sphere) and fixed volume, is there a way to define a specific number of meshing elements? I am trying to solve my system with a specific number of elements and...

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electrohydrodynamic problem

Hi all, I'm currently simulating the electromechanical effects of water droplets under both AC and DC voltages. The water droplet is placed between an energized and grounded electrode on an insulating...

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Generation of thicker boundary layer mesh

Hello guys I wanna make some think boundary layer meshes. In my simulation, the boundary layer thickness delta is so big in that Re_x = 9.8 and delta = 5.0x/sqrt(Re_x). So I think the boundary layer...

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Permanent magnet machine modelling!

I am simulating a permanent magnet generator, in 2D Comsol, 'emqa', 'ALE' mode. But there is a problem concerning magnetic circuit saturation as the followings: - My programs are convergent with linear...

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How to find what "compute differential" documentation

When I am plotting a Nyquist plot, I came across this option "Compute differential" under "Expression evaluated for:" option. I just don't know what this means. But instead of asking what it is, I want...

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Error: 'Non Linear Solver did not converge'

Hi, I am working a a 2D model of a rotating machine. I am using the material soft iron (without losses) from the ACDC material library. Every time I use the HB curve as the magnetic field constitutive...

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Magnetic Force on an armature

Hello I'm dealing with a very simple problem that has been very frustrating for me! I would appreciate if any one can assist me with that. I'm modeling an E-shaped core in 2D magnetic field module. It...

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Large Eddy Simulation

hello I want to use Large Eddy Simulation on comsol but I can't found it. Can you help how to do this. thanks a lot

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Base vector coordinate system

I am modeling the anisotropic behavior of a plate that have fibers oriented in different directions. For this purpose, I am using the structural mechanics feature. I am orienting my fibers using a...

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Initial negative concentrations

HI All, I am trying to simulate a A+B-->C chemical reaction. I dont know why my reactants (A and B) concentration is going negative. How do I fix this? I have attached my model as well as pic of the...

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Creep - Plasticity

I want to use the non-linear structural mechanics module for simulation of plastic deformation by yielding. There is a creep module and a plasticity module. In the creep module, I find more suitable...

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import particle positions in Particle Tracking

Is it possible to import particle positions in COMSOL for particle tracking? If not, can you add one, please?

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how to do moving mesh in 4.2a

Hello everyone I am implementing a rectangular piezoelectric converter, in which i want to be vary the length and width of the piezo layer via moving mesh ale. I studied one of the paper of "Thickness...

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Countor data set does not generate plots

Hi, I´m solving a very easy Laplace equation on Comsol, I would like to extract values of some variables I´d define along the isolevels of another user define variable. I´m able to create the Contour...

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Fluid flow with a moving solid object/hole

Hello, I would like to model the airflow in a room occupied with people, and to allow the people (cylinders) to move around in the room. Is this possible in COMSOL? For a silly example in 2D: I have a...

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export mesh data for an explicit selection

Dear all, I am a relatively new user COMSOL with a lot of Finite Element experience both on the programming and theory level. I started with COMSOL today which went actually quite fine and fast. I...

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optical fiber modeling

Hi everybody, I'm dealing with a very simple problem that has been very frustrating for me! I would appreciate if any one can assist me with that. I am performing a simulation of light coupling...

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