Waveguide amplitude errors, scattering boundary condition
Hello everyone! I am modeling a waveguide with the purpose of verification, but I am getting high errors in amplitude when the length of the waveguide is not a multiple of the wavelength of the...
View Articleaccuracy in evaluating refractive index
Hi, I am using RF module > perpendicular mode in order to simulate the distribution of modes and get the refractive indices, when I use related m.file of the geometry ,I get refractive indices with...
View ArticleEvaluation of calculated parameters on a specific grid of points
Hi all, I am doing some calculations on solenoid magnets and would like to get the magnetic flux density vectorial components at specific points of a helix that are defined in an external file. I would...
View ArticleMagnetic Force on an armature
Hello I'm dealing with a very simple problem that has been very frustrating for me! I would appreciate if any one can assist me with that. I'm modeling an E-shaped core in 2D magnetic field module. It...
View Articleadvice for simulation set up or suitable tutorial (3D stress distribution...
Hi All, I am trying to help my fellow Orthodontics to showcase COMSOL's ability to simulate one of his problem. But I am struck and getting inconsistent results. The simulation is very basic and...
View ArticleModel couplings: Integration vs. Summation over nodes
Hello, I am working with two modules Structural Mechanics and general form PDE as coupled. I need a model coupling to define an integration. When I choose "Summation over nodes", my model works fine,...
View Articleabout heater simulation in the room
Hello! I am use comsol 4.3a , and use the non-isothermal flow physics to simulate the heater in the room. And the room has a door , and I want to set the door is open, and it is connect to the...
View ArticleOptimal parameters in a GMRES solver with GMG preconditioning
Hi, I am solving a high-frequency 3D acoustic problem with millions of DOFs. Documentation suggests to use a GMRES solver with GMG as a preconditioner. However, it gives very little details on the...
View Articlefailed to evaluate jacobian in using velocity field in fluid particle tracing
Hi, I have tried to edit drag force's equation view in fluid particle tracing(fpt). COMSOL for example, uses "model.input.u1-fpt.vx" for relative velocity in x direction but when i use it in my...
View ArticleFlow between parallel plates
Hey, I am trying to model flow between 2 parallel plates both of which are moving towards each other. The equations applicable are Continuity and Navier Stokes. However, I am quite not able to find the...
View ArticleHeat transfer from the pipe to surroundings
Sir, We found three options for "Wall Heat transfer" in "Non-Isothermal Pipe Flow" namely 1. Temperature (nitf/nitf) 2. Temperature (nipfl/nipfl) 3. Userdefined. (with an option to check "Take average...
View ArticleMeasuring the temperature at a point
Sir, In a non-isothermal pipe flow model, we have specified wall heat transfer with external temperature as 293.15K and the check box for taking average from adjacent domains is also checked. After...
View ArticleFailed to evaluate variable in particle tracing module
Hello! I'm trying to simulate particle temperature in particle tracing module. But, when I try to plot a line graph of particle temperature, I see this: Failed to evaluate variable Variable - mod1. Tp...
View ArticleScatterer on substrate, RF module
Dear All, Probably some of you RF module users saw module “Scatterer on substrate” in model gallery. I have question about that, and I have question about total field formalism in generally. So, basic...
View ArticleMoving items relative to each other
Hello, I am a beginner user, and I was wondering if anyone could help with my problem. I am trying to calculate electrostatic forces between objects, as one is moving relative to another. Must I create...
View ArticleMapped mesh in 3D
Dear all, 1-I trying to mapped mesh a solid in 3D, but it sends me an error message "Error: 7161:The mass matrix is zero" when i try the eigenfrequency, and yet if the default mesh does not send it....
View ArticleError with mesh change
I made a simple eigenfrequency study with a beam using a Free Tetrahedral mesh and it worked fine. But, when I change the mesh type to Mapped and define the size of elements to 5mm, I received an error...
View ArticleHyperelastic Material Models
Are there any talks about COMSOL implementing other hyperelastic models like Yeoh, Ogen or Arruda-Boyce? Thanks.
View ArticleEigenvalue analysis " Mass matrix is zero"
I am trying to run a Static Eigenvalue analysis of a structure . My model is a stone-building , so i just enter the properties of the material and the constraints . When i solve the problem appears the...
View Article"Failed to compute elastoplastic strain variables" Help Please
Hello, I am an absolute beginner at COMSOL Multiphysics and I am trying to model the effect of the movement of soil on a steel pipeline buried in it. I have attached the model file with this post. I am...
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