How to activate equations (used in heat source) for particular temperature? And how to intepret them into the heat source (Q)
Hi! i cannot understand how to apply an AC voltage to an electrode. Could someone provide some guidance?
Hi all,
So here's my problem. I have an antenna connected to a 175 W amplifier via a waveguide. It's transmitting power to a nozzle (essentially a receiving antenna) approximately 1 m away. I am trying to determine how much power reaches the focal point of my parabolic nozzle through post processing.
I am new to COMSOL, so if anyone has any suggestions on how to do that, they would be greatly appreciated! Thanks a lot.
Hello,
I wonder how to obtain the mass and stiffness matrices of the problem I am working with. The structural problem is modelled using 3D shell elements, with a total of 624 nodes of which 12 nodes are constrained, i.e. with 612*6=3672 degrees of freedom. My intention is to obtain the mass and stiffness matrices of the constrained structure, i.e. the matrices with size (3672x3672) and the description of the degrees of freedom. The livelink for matlab function mphmatrix gives me either:
Unconstrained mass and stiffness matrices E and K with size (14832x14832)
Constrained mass and stiffness matrices Ec and Kc with size (12240x12240)
I don't understand why the constrained matrices have more degrees of freedom than: number of degrees of freedom per node x number of nodes
Kind regards,
Lucas
The below post is related to an archived discussion
[start here] Hello everyone, I have a really nice machine in the lab with windows 10 server. I have Comsol version 5.5 installed. I am trying to run an CFD module computation, where I am trying to create a fine mesh.
But I find that though my computer has 512GB of RAM,when i am trying to create a fine msh ,the comsol only uses 2GB at the beginning，after an hour it just rase to 10GB. Also,I have a 96 core CPU.
Coule anyone please explain to me if there is a way to overcome this problem. did anyone else have the same problem?
Thanks in advance.
Hi Richard,
As you know about our RF heating project using a cavity and antenna. I am not sure how to excite a cavity by using a slot feed. could you advise me on
A) how to make a slot in the top surface of a rectangular block
B) what type of port I need to apply.
C) anything else please?
Best regards, Azeem (Freshseal Ltd Telford)
Hi there, I hope to simulate heat drives the groundwater flow. can I use the Darcy's Law and Heat transfer in porous media ? Imagine a porous medium filled with water, where the pressure is distributed according to the hydrostatic pressure. After the bottom is heated, the pore water will flow under the thermal drive. When the temperature is high enough, will phase change occur? which interface should I use? How to simulate? Thanks a lot~~
Hi,
I've created a Composite material in the COMSOL Composite module and I would like to make an equivalent anisotropic bulk material to simulate in Solid Mechanics to get a rough idea of the effect of geometric features that can't be modeled as shells. Using the Cell Periodicity I have already created the anisotropic material. Since this doesn't account for different fiber orienations, I was wondering if anyone has been able to create a material that can account for this or knows how?
Thanks, Wil
The below post is related to an archived discussion
[start here] I am using 5.5 version and have the same problem. The walls are defined in the wall catagory and I have tried, without changing anything else, the following wall conditions bounce, diffuse scattering and isotropic scattering, Mixed diffuse and specular reflection (probability 0.5) general reflection (x=3m.s, y=-5m/s reflected velocity). The software seems to be ignoring the walls?
When I used Comsol with MATLAB to do optimization problems, MATLAB always iterated to a certain number of steps before an error was reported. I noticed that comsol's server was automatically shut down at this point. Can you give me some advice?
Hi all, So here's my problem.I am trying to to simulate a motional current load that when the material is ablated under the action of electric current, the current will be loaded on the material which is not ablated below. Is there any way to do that? if anyone has any ways on how to do that, they would be greatly appreciated! Thanks a lot.
I wonder how the degrees of freedom are organised on the eliminated stiffness matrix exported from a 3D structure composed of shell elements. The structure has no constraints, as I want the free-free frequencies and mode shapes, then I was expecting eliminated mass and stiffness matrices of size equal to the (#degrees of freedom) = (#nodes) * (#dependent variables). However the eliminated matrices have a size equal to (#nodes) * 5.
I know shell elements nodes have only 5 degrees of freedom, but since they are not on the same plane, I was expecting 6 degrees of freedom per node, not 5. If someone can explain-me how this matrix is organised, I would be very grateful :)
Best regards,
I have a planar inductor model and am trying to simulate the geometry coil analysis. But for some reason I'm getting the following error:
"Errors when compiling equations:
Inconsistent circuit setup. The circuit contains hanging nodes.
-Node name: 0 -Feature: Ground Node 1 (gnd1)."
dear sir; i'm working on eddy current testing, i'm working with two idependent coils, one for excitation an the other dor pick-up coil, but how can i make pic up coil (without excitation just the effect of induced current)? best regards
hi, please suggest how to model piston moment in tube. I am trying with two phase flow moving mesh. I used Navier slip at wall water boundary and normal mesh displacement for piston but it's not working.
PROBLEM: I am looking into a way to simulate solar cell with photovoltaic effect (occuring in semiconductor) and resistive losses (in metal contacts).
Semiconductor is simulated using Semiconductor (semi) physics and the dependent variable is electric potential V (as well as Electron solution varibale and Hole solution variable). Metal contacts are simulated using Electrical Currents (ec) physica and the dependent variable is also electric potential V.
By default, Comsol does not offer physics coupling. On the other hand, the problem is quite simple, I need continuity in current flow at the boundary, where the 2 physics meet.
QUESTION: How to assure continuity in current flow at the boundary of Semiconductor and Electrical currents physics ?
Hello everybody!
In a plastic perfect simulation (2D-Axial) with large deformation, the software was not be able to evaluate 'comp1.solid.Fiil22' defined as "comp1.solid. Fpi22". I searched the last one on "equation view" section but i did not find it, I'd like to know how It is defined or how I could do it.
Thanks.
I want to study deformation of viscous particles under the influence of a fluid flow, while passing through a constriction. Here properties of the particle and fluid are different. Are there any tutorials similar to this study? What modules and properties need to be defined for the particles of this nature?
Hi there,
I have a simple model with a few cylinders on top of each other, each made up of a specific material. I also have a .txt file that specifies some 100 points by their x-, y-, and z-coordinates (three columns: x, y, and z). I wonder if there is a way for me to import the coordinate information into comsol and have comsol produce a new table with four columns: x, y, z, and some other material property of my choice. I have created a variable for the material property of interest, but I'm stuck at importing and processing the xyz coordinates. Many thanks in advance for the help!
Best, Max
Can any one help me with a comsol file for bistable cantilever or Nonlinear cantilever system or Nonlinear bistable energy harvester dynamical system or Magneticaly coupled cantilever system something like this.
please help me with this ,