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Heat loss in hydraulic hose

Hi, I'm working on an project where it's in my interest to find the heat loss to the surroundings, from the hydraulic fluid inside a hose. I have access to Comsol Multiphysics 4.3 through my work and...

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Scaling of motional mass

Hello everyone, Thanks to this forum I have found out how to calculate the motional mass for different vibrational structures. The calculation of (MPF_mod1.u^2)/(TotalMass) and for v and w gives a nice...

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Problems with boundary layer meshing

I am trying to mesh a k-epsilon model and cannot generate a boundary layer mesh. My model has a very narrow region and I expect that that is the problem area. The error I get most often is: Could not...

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SPIRAL HEAT MODEL

HI, Just i want to know howl can i change the height of the COSOL spiral heat model, it's around 6mm, and i want to make it at 60 mm thanks

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How to analysis a muffler(decibel & Frequency rate of outlet)? please help!!!!

Hi guys! I have a model muffler of an exhaust that will to analysis. i will to measure Sound intensity(db)& frequency of outlet. i show a picture of my muffler in this picture(I show inlet &...

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Problems about Periodic Conditions in the tutorial model “Periodic Boundary...

Hi all, Recently I confront one confusion about periodic conditions in the tutorial model - Periodic Boundary Condition. In Periodic Condition, it selects only boundaries 1 and 6 which are parallel...

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How to define AC voltage and the direction of AC current in comsol

Hello, guys: I am a new user to Comsol and I am currently doing electromagnetic single phase power transformer model using comsol. The Physics i am using is Electric Currents (ec), Magnetic and Fields...

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Error: Unknown property: funcname

Hi, I have defined a MATLAB function which is called by COMSOL. I get an error message such as: Undefined value found. - Detail: Undefined value found in the equation residual vector. There are 2128...

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Plasticity

Whats the difference between Small Plastic Strain and Large plastic strain? How is a model with contact and friction to simulate? What is important? My models usually have convergence errors when I...

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Continuing Modeling Issues with 2D & 3D piezoelectric SAW model

Hello all, I’m in desperate need of help with my model. The initial model setup is a 2D cross-sectional SAW device where I have silicon, a metallic electrode as my ground, a buffer layer, a...

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Particles traveling through boundaries

Hello All, I am attempting to use the particle tracing function on a laminar flow in a small channel with obstructions in the channel. I modeled the design after the lunchtime seminar on the particle...

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Eigenfrequency seems right, but displacement units are totally wrong.

Dear Comsol Community, in the model attached I have a 20 micron long beam using the Solid Mechanics module to get the Eigenfrequencies. I calculated them manually using Euler-Beam theory and the first...

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Preparation of figures for papers/thesis?

If it has been written somewhere, can someone point me to where there is a guide to producing figures from 2D plots? I am using COMSOL 4.2a, and want to use some surface plots alongside legends of the...

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RF Source

Hi, I want to apply a current or a voltage source to a rectangular surface in a COMSOL RF module problem. Would you please let me know how I can do that? Regards, Elham

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must i compute the whole programe again?

Hello, I am a beginner of comsol. Most of the time, i made mistakes and got different solution from references. Then i changed Model settings and tried to find the right solution. But usually it take...

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Modelling Metallic Diaphragm

I am a novice COMSOL user using the software for a student project so apologies if my problem below seems simple. I have a 2D axisymetric model of a thin metallic diaphragm (approx 25mm di and 0.025mm...

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Limiting simulation volume/area or displacement for mechanical model

Hey, while doing a buckling study of an optical fiber I tried including a fixed box around the fiber to constrain the movement of the fiber within this box. Sadly this increases the required simulation...

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Heavyside-Function and Divison by Zero

Hi I stumble realising a Gaussian-beam like in the tutorial model "Nanorods" (using RF-module). Problem: Part of the wave function has a singularity: constant/z Solution in tutorial: Define a...

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How to implement a biphasic asymmetric waveform?

Hello everyone. I'm trying to figure out how to implement a biphasic asymmetric waveform in Comsol 4.3a. I need to be able to use the following electrical simulator settings in order to stimulate an...

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Adding a Faxen Force on Stokes drag force in Particle Tracing Module

Hi everyone, I am trying to use the particle tracing module with a non-uniform laminar flow in a channel. I am using "Drag Force" to trace the particles' motion. However, the Stokes force is defined...

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