Global parameters vs. Model/Definitions/Variables
It seems that the geometry can only be defined by global parameters while the rest of the modeling can also use variables. Is there a way to access the model variables in the geometry such as...
View ArticleCalculated initial values NOT the same as specified
I have seen this now in 2 simulations... The initial values specified in Initial Value Domain nodes are NOT the Initial Values the solver ouputs, either at t=0 of the solution nor when asking the "Get...
View ArticleInitial carrier concentration of diode example
Dear Comsol users I'm trying to solve the semiconductor diode example from the model library under no applied bias. I'm only interested in the carrier distribution in equilibrium for now. 1) In the...
View Articleyield stress
Hi I'm trying to understand how can i define yield sterss for a bingham plastic material in COMSOL. The stress expression for this model is: shear stress = yield stress+m*(shear rate) Any comments on...
View ArticleCreating Geometric Entity from Iso Surface
Is there a way to create a geometric 3D entity from a region in the results that has a solved field value that is less than or equal to some constant? In this way I could conveniently do averages over...
View ArticleHow to creat TE plane wave in Comsol 4.0 RF module
I am a new player in Comsol 4.0. My question is : How to creat ideal TE plane wave in Comsol 4.0 RF module? How can we know the wave produced is an TE plane wave? I tried three methods as mentioned in...
View ArticleMismatch between calculated answer from Comsol and Matlab
Anyone know why the result generated from Comsol (4.2) different from the result calculated by using Matlab? I am doing 2D mode analysis for photonic crystal fibre, i draw and defined all parameters...
View ArticleNew user-defined material
I'd like to add a material to the user-defined materials list. I've looked through the manual and don't see how to do this. Furthermore, there are no materials in the database that seem similar enough...
View ArticleHow to reduce the model file size
Hi, I built a 3D heat transfer, time dependent model. After simulation, the model file goes beyond 5G. Is there anyway I can reduce the file size? I only care how the maximum temperature changes with...
View ArticleMoving laser
I'm a simulation a moving laser though a zinc pill, the problem is that i can't move the surface with the heat flux, the thing is that if i use a Parametric sweep Comsol will compute one point and...
View ArticlePrincipal stress 2d vs 3d
Hi everyone, I have the same model made in 2d and 3d. First and second pricipal stresses are similiar in both models. But third principal stress in 2d are unrealistically high, however in 3d have value...
View ArticleExtracting absorbed power
Hi all! I am currently doing a 2D model where I have an incoming power, and then I have absorption within the material. As a result, I have the value of the intensity everywhere, but I don't know how...
View ArticleComsol 4.2a Requirements
Dear All, I want to buy new computer with which I want to do simulations around 700 000 - 1000 000 number of degrees of freedom. I of course thought about desktop PC, i7 processor, 24 GB work memory....
View ArticleDisplay time-dependent solutions in units of years?
How can I display (in a legend for a plot to be specific) my chosen solutions in different units than seconds? I am dealing with thousands of yeras, and a legend with entries like 9.46728e11 is not...
View ArticleIncomplete instruction for Model Library example (Sliding Wedge)
Hello, I'm trying to create a model from Model Library, using only pdf instruction. The model is Sliding Wedge (Structural Mechanics Module/Contact and Friction/sliding_wedge). The problem is, that a...
View ArticleDifferentials ux and external functions
DEar all, I haven't found any answer in the external function section of the user's guide for what appears to be a really simple question. I need to create an external function which will simply...
View Articleabbreviations for physical parameters
Dear all; I am learning comsol for specific models and found a potential of comsol for the models. But, I am not sure how to input diverse physical parameters such as strain rate in the equation. For...
View ArticleUnits not considered
Hi I define a constant NA with units cm^-3 and a function f(x) = NA*exp(-(x/k)^2), where 'x' and 'k' are in meters making the units of f(x) essentially cm^-3. However, in the variables list, where I...
View ArticleLoad in movement
Hi all, Is there any way to simulate a LOAD MOVING along the boundaries of my object (2D)...so I can see how it deforms as the load passes? Im using the solid mechanics module--> BOUNDARY LOAD??...
View ArticleBending loss in PCF
I want to find out bending loss in PCF using COMSOL 4.2 software. How i will get bending loss from this software. Samiul
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