CAD import file boundary conditions
I have a 2D model I've imported from CAD that consists of many interlinked hexagons making up a larger hexagon (like a big hexagon with smaller hexagon-shaped holes throughout). I'm trying to do a...
View ArticleBoundary conditions in Equation-Based Modeling
I am trying to solve a set of three "Helmholtz-type" equations using the Equation-Based Modeling of Comsol. There are three independent variables, call them u1, u2, and u3. The equations are (with some...
View ArticleALE+ PDE form
hi all. I have a PDE coefficient form for evaporation of fluid in a fluids mixture. The governing equation has the general form of: d(X)/dt=d{D(X,T)*d(X)/dz}/dz in above X is the evaporating fluid...
View Articletumor ablation model
hello, i am trying to make a model like" tumor ablation" model in comsol Heat Transfer Module but i want to change the current from DC to AC current and i want to plot the electric field distribution,...
View ArticleCan I suppress breaks if there is an error?
I have a model that I would like to run in a parameter sweep. However, some of the parameters I give the model fail to yield stable solutions and hence cause a break. I don't necessarily know...
View ArticleLine maximum - data manipulation challenge
I need to take a series of derived maximums (for Temperature, say) from a regular array of parallel lines which are perpendicular to the y-z plane and pass through a bounding box in 3D space. The data...
View ArticleHelp with Tracer Dye Profile in Laminar Pipe Flow
I am new to COMSOL. I am currently in a Finite Element class and we have an educational license for Abaqus, but as the lone environmental engineer in the class it doesn't provide me with much useful...
View ArticleConverting a circulator into an isolator
HI!! I have implemented the '3-port circulator' example provided with the rf module and now I want to convert it into an isolator.After some search on the internet I have found that a circulator can be...
View ArticleSteam
I'm working with steam and condensate phase shift. I wonder who can help me with the correct handling of steam?
View ArticleHelp. contact pair penetrate each other.
Dear, all, I have a basic question regarding to mechanical contact. I have just run a very simple simulation: a deflected beam contact a fix cubic. However, I always got penetrated displacement of the...
View ArticlePoisson-continuity coupled equation
Hello, I try to model the corona discharge in wire-cylinder geometry governed by the equations: nabla (V) =- rho/epsilon0 (Poisson equation) and grad (rho) * grad (V) = rho ^ 2/epsilon0 (equation of...
View ArticleStep function
Very simple question, but I can't find out how to do it. I have a external temperature, "Temperature 1", which is 100 C. After 330 seconds I would like it to drop 80 degrees to 20 degrees. I should be...
View ArticleFail to evaluate the derivative at a line
Hi, I am using COMSOL 4.0 RF to model light scattering. In 2D model, i calculate a very thin sheet scattering, which is 1D geometry in such 2D model. So i use the surface current boundary condition for...
View Articlemodeling evanescent wave
Hi all, How to generate or simulate evanescent wave in COMSOL? can total internal reflection work? There seems to be rare examples in this field and expect for any ideas from you.
View ArticleModeling a Diode
Hi, I am trying to follow the example of semiconductor diode available in:www.comsol.com/showroom/documentation/model/114/ in a COMSOL 4.2. I believe that I have followed exactly what is describe in...
View ArticleCan I use COMSOL to solve integral equations?
Dear all, I have some integral equation to solve. Can I do that with COMSOL or I always need to change it to PDE? Thanks a lot!
View ArticleCapillary filling changing area
Dear all, I have been working on a simple 2-phase flow through a capillary. The next step in my model is for the fluid (water) to leave the capillary to a duct with a higher surface area. The model...
View ArticleQuestion on objective function for 'horn_shape_optimization' for own design
So I understand the objective function is: -10*log10(0.5*realdot(pm,pm)/2e-5^2) which makes sense when reading literature but when looking at the definition of 'pm':...
View ArticleEnforcing variables to be greater than or equal to zero
Hello, I'm modelling diffusion through a porous medium with adsorption. The main dependent variable for mass concentration tends to go below zero which is not true in reality. Is there a way to enforce...
View ArticleHelp me please! how to draw the magnetic field lines in 3D, as
Hi all! I need to add the magnetic field lines (and possibly add metal bars between the head and emitter) to the model 2190 Absorbed Radiation (SAR) in the Human Brain. PS Since I'm a beginner, then I...
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