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defining temperature of inlet fluid?
Hi How do I inject a fluid with a required temperature through an inlet? Obviously it's temperature needs to be different from the initial fluid in the model . thanks Dave
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transport of diluted species in microchannel
Hi all, I am trying to calculate the concentration profile of two species with different diffusion coefficients in a narrow tube. The physics I'm using is " Transport of diluted species" for the...
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Vibrations: Eigen Frequency Analysis
I understand that Eigenvalue=(Eigenfrequency)^2 , where eigenfrequency is is in Rad/second i.e angular velocity. To get cyclic frequency we divide eigenfrequency by 2 PI i.e. f (Hz)= eigenfrequency/2...
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Simulation not terminating once error is smaller than defined tolerance
When using comsol 4.4 (and using segregated groups) to solve a problem involving natural convection, I am noticing that simulations do not stop even when the error in each group is below the defined...
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Using a function as an input to simulate turn-on turn-off sequence
I'm using the Joule Heating module and I'm modeling a simple wire heater that heats up when I run a current trough it. I want to see how the temperature of the heater decays as a function of time in...
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Temperatures calculated but thermal expansion calculation is missing ?
I generate a quite simple 3-D model: A cylinder made of copper with a radius of 0.2m and a height of 0.5m and heated at its mantle with a total energy of 1000 Watts for one hour. Within this cylinder...
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Error in eigenfrequency study
Hi, I am trying to run a vibration analysis on a part. I used the Solid mechanics module and the Eigenfrequency study. I specified the boundary condition, the loading and the material. But when i...
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Interrupting Parametric sweep without loosing results
Hi, i'm running a large parametric sweep which turned out to dramatically slow down during the last few combinations. My machine has been crunching for days now and i'm wondering if there's a way to...
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Time dependent study with Transportation of Diluted Species in COMSOL
Dear All, I am simulating transportation of target molecule to bind with probe molecule in a particular spot in flow system. I can see the increasing of the concentration of complex occurring from...
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total flux condition
Hi everybody, Does anybody know how to introduce the Robin condition (total flux condition) for the chemical species transport module? Thanks, Joana.
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Average over a parametric sweep
Hi, I have a parametric study and would like to plot the average of an expression. E.g: parameter alpha=0,1,2,3 then I would like to have an operator like average(expr,alpha,list_of_values) Is there a...
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Mutlitphysics node needed? For heat transfer through solid and through fluid...
I simulate heat transfer through a water volume (cylinder shape) totally included within a copper cylinder. I assign the materials "copper" to the outer cylinder and "water" to the inner cylinder. I...
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Problem to eddy current response in 2D modeling
I built a model in COMSOL 4.3a using AC/DC module to simulate eddy current response excited by a linear coil. A sin wave is used as excitation signal in a linear coil, and the response of eddy current...
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Pulse input Rectangular Waveguide
Hi everyone, Is it possible in comsol to give a pulse shape input to a port of rectangular waveguide as a power source.? Actually I want to heat a certain material inside a rectangular waveguide for...
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Natural Convection in simple 2D geometries not converging (despite several...
I am trying to use comsol 4.4 to solve natural convection problems in 3 very simple geometries (cavities). I have considered two flat geometries and a cylindrical geometry. One causes no problems to...
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Error:"Variables property does not include all degrees of freedom in xmesh".
Hello, I have tried to simulate two groups of cylinder permanent magnets and try to calculate the magnetic forces. I use Swept mesh for the magnets and Free Quad for the air (which I use a big sphere)...
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Force required to constrain bending
Hi, suppose I have a tube fixed at each end. COMSOL can compute the sag of that due to gravity. No problem. But suppose that sag is constrained - the sagging tube has reached the floor and can sag no...
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3D model with two crossing symmetry planes
Dear Comsol users, I'm doing simulations with a 3D model, which has two crossing symmetry planes (xz and yz). Therefore it would be enough to simulate just a quarter of it. Now I wonder how to set up...
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How to find out about the variable name phys.Solid.sl (in an error message)
I get an error message:"Tensor inner product failed. Tensor product must a least have rank equal to 2.""phys.Solid.sl:item.alpha" How can I find out where and how the variable...
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out of memory in stationery solver
hi, I designed a MEMS piezoelectric accelerometer and trying to simulate in comsol. I am getting the error every time I compute " out of memory in stationary solver"... Please help me to solve it......
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