Two-phase flow including both incompressible and compressible fluids
Hello! I've been struggling to construct a Comsol model that simulates two-phase flow, in which one fluid is water(incompressible), the other is air(compressible), which can reach Mach number of around...
View ArticleUnexpected error
Hi every body, I am using Comsol 4.2a. I would like to modify material constants but when I try to do it appears "An unexpected error as occurred". I try to make a new file with only one rectangle and...
View ArticleDerivative of Interpolation Functions
Dear all, I am trying to understand if, given an interpolation function (defined by a table of points in an external file like *.txt file) it is possible to define the derivative (spatial) of the...
View Articleintegrating a lookup table for frequency dependent variables
Hi everyone, I have created a lookup table for frequency dependent values of epsilon_r. This table includes two interpolation functions: one for the real part (eps_real) and the other for the imaginary...
View ArticleTemperature effect in Electrostatic module.
Hi, I am using Comsol ver 3.5a. Can anyone guide me that how could i observe the effect of temperature on capacitance value in Electrostatic module ? From where i can change/control the temperature in...
View ArticleResonating magnets
Hi folks, Me and my team-mates are working on a project and we now need to simulate a design we made. We have a tube with a length of 10cm and a diameter of 2cm. At both ends of the tube, say x = -5cm...
View ArticleMultilayer structures: multiple Rectangles or one Rectangle with Layers?
Dear all, I am dealing with multilayer structures, and I have a small doubt: modelling a multilayer, do I get the same results (and of course the same physical meaning) using: 1) different rectangles...
View Articleset path of the external matlab function
Hello all, I am trying to run a Matlab script of my model which in turn uses an external Matlab function. When I run the model from matlab, comsol opens a new Matlab process and tries to call the...
View ArticleElectric field not adjusting with moving mesh
Hi, I have created a model which is effectively a capacitor with a moving plate. I have ground electrodes on the fixed top plate and +/-100V electrodes on the bottom moving plate. I am using ALE with...
View Article2D AC Coil Setup for Magnetic Induction Tomography
Hello, I have managed to create a simulation of a coil in 2D, using just a magnetic field source, however I would like to replace this with a frequency dependent magnetic field. How would I do this?...
View ArticleSolidworks model meshing issue
I created geometry of a saddle coil pair in Solidworks and then I imported it to COMSOL using the geometry import option. When I build meshes, it gives error of meshing around edges and corners. COMSOL...
View ArticleTime Steps
While simulating our case, we have used strict time step with maximum as 1800 seconds. But still, it is taking a time step of 0.1 sometimes. This is making our simulation quite slow during the middle...
View ArticleConvergence Problem: Error smaller than Tolerance
Hi everyone! I am trying to model non-isothermal, reactive fluid flow in a channel with catalyst-coated walls. Therefor I couple the "Transport of Concentrated Species"-module with the "Non-Isothermal...
View ArticleComsol 4.2a Java error with Mac OS X 10.8.3
Hi every body, I am coming back with my "unexpected error". It seems that it should coming from Java. I am working under Mac OS X 10.8.3 and with Comsol 4.2a It appears an expected error with the log...
View Articlefailed to generate mesh for face
hello, i imported a solid geometry to comsol, but when i generate mesh i get error: failed to generate mesh for face, i tried to make custom mesh for these faces, but did not solve the problem. can...
View ArticleDiaphragm
Hi, I am trying to do simulation of air horn diaphragm, Inputs: Diaphragm dia and thickness and material property. Input pressure on diaphragm. Output: Max deflection of diaphragm. Kindly provide me...
View ArticleSimulation time for 2D and 3D vastly different (with comparable DoF)
Hello, I have a question regarding relative simulation time for 2D and 3D structure. I am using COMSOL RF module to simulate an optical structure. When I try a 2D case with very fine mesh density and...
View ArticleParametric sweep and geometry change
a,b,theta_a and theta_b are global geometry parameters. theta_a = 2/a, and theta_b = 2/b. a,b,theta_a, and theta_b are all used in geometry creation. I am running a parametric sweep for parameters a...
View ArticleDiscrepancy between particle trajectory and streamline?
Hello, I'm trying to teach myself how to use the particle tracing module, so I'm modeling a simple T-junction microfluidic channel. I get an unexpected result, however, when I trace the particles....
View ArticleParameters calculation
Hello, I would like to ask if anyone know where I could find a full list or a list of the parameter comsol calculates when solving a model?. For example I know for piezoelectrics Y11 corresponds to the...
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