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stratification
Hi everyone! Let's picture three objects densely pressed to each other. First object is heated, the other one is cooled, and the third is in between. Certain temperatures cause a gap between objects...
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rigid solid 2D axisymmetric
I have created a 2D axisymmetric and I want to make one of the elements a rigid solid. However I cannot find the option in the right-click menu of the physics node. It usually is in domains in a 3D...
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Heat exchanger
Hi I have a question regarding modeling an air-air heat exchanger I hope you can help me with. I have a serpentine flow pipes and a box for the air forced convection. I started with a very simple...
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Error message after compute, modeling CFD of equipment in tunnel, advice? [CM...
Hi, I'm a very very beginner in using COMSOL Multiphysics 4.4, I've never used it before, but I've done some tutorials from the installer. Now I'm trying to compute this model (can be seen attached,...
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Directional Coupler
I am trying to model a directional coupler in 2D. I get the following error Undefined value found. - Detail: Undefined value found in the equation residual vector. There are 1 degrees of freedom giving...
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Pressure in Earth crust
Hello, I am trying to model the Earth crust. My model is 50 km * 30 km and in 2D (plane strain). I am using the solid-mechanics physics with linear elastic material. Fora first test, I chose E =...
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Fixed Beam Deflection
Hi, I have a circular beam fixed at both ends using "Beam" physics and "Stationary" study. By applying an edge load on the beam I would expect to observe a deflection of the beam. In contrast only the...
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Material Properties setting problems in AC/DC Module
Hello, I've created a simple 3D model in the AC/DC Module. When I'm viewing the geometry using the select domain option I can view and select all of my 10 domains. But when I go to assign materials to...
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Laminar flow of Carreau fluid with variable density
Hello, I am using the Laminar flow physics together with the Carreau fluid properties and I was trying to write a formula for the density as a function of pressure 'p'. From my experimental data I have...
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Compressible Navier-Stokes with Non-newtonian viscosity in PDE module
Hello, I am new to COMSOL and I've been trying to model some incompressible Navier-Stokes system with variable viscosity, a Carreau viscosity to be specific. I have used the CFD module to model this...
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Truss interface - excitation
Hello, Since I read that the truss interface can only sustain axial forces, does anyone know if I could do a frequency domain study and excite the system by a transverse force? thanks, Nicolas T.
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Dynamic stiffness of rubber bushing with static pre-load
Hello, I am interested to model a rubber bushing and to calculate its dynamic stiffness (frequency analysis). The bushing is pre-loaded, which means it could have large deformations. Any good advice on...
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2D-Axisymmetry not considered for domain probes in the calculation "Average"...
Is the 2D-axisymmetry not considered in the calculation of domain probes? I learned, that I had to check the checkbox "Compute Integral in revolved geometry" when I wanted to calculate the correct...
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How to limit time step size, when time depend solver neglects Nyquist Theorem?
I have a boundary condition: Boundary Temperature varies as: 293.15[K] + sin(t/100[s]) * 1[K] The Time Dependend Solver generates a time series beginning with 0,1,10,20,40,80,160,320,640,1280 ... where...
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beam buckling analysis
Hi, I am trying to analysis a beam buckling under gravity with different boundary conditions. It can be fixed-free or fixed-fixed but slided in one direction. Can anyone give some suggestions about...
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full model of a coil spring?
Hello, I'd like to model a coil spring, to include changes in diameter due to compression, and longitudinal and torsional modes. Is this a reasonable task for Comsol, or would it be prohibitively...
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Analytic expression
Dear, I want to write an expression for sine wave which is time dependent. The parameters are the amplitude is 3, duration of the wave is 0.1 milliseconds and the frequency of waves is 150 Hz. I tried...
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how to set two conditions for one boundary condition(vector)?
Hi all, I want to define two conditions for one part of rectangular that I have in 2D (xz) and put two different value of pressure head in one boundary condition, like Hp=0 if z>= - 0.5159m and...
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problem with piezoelectric impedance two method
Hello, I use two method to calculate piezoelectric impedance. method 1: I use (pzd.Y11) to calculate impedance of piezoelectric. method 2: I use Electrical Circuit (cir) coupled with Piezoelectric...
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Piezoelectric Power Output Visualization
Hi, This is probably a simple question but what the heh. Lets say I have a simple energy harvester beam model fixed at one side and supplied with a body load at the other. This body load is simply...
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