Piezo energy harvester
Hi, I'm new to this Forum, greetings to all. I am studying on piezoelectric energy harvester, trying to simulate the power output of such an device with COMSOL. I know that there are other discussions...
View ArticleScttering problem using comsol4.2
I wanted to calculate scattering absorption cross section and thereby extinction for a nanoparticle. I am not sure how to go for that in comsol4.2. Can anyone please tell a basic flow to accomplish...
View ArticleCOMSOL 4.3a Installation Problem
After installing 4.3a, whenever I open most files (or try to at least), I get the following error in a pop-up window:
View Articleselection of physics
Hi friends i am trying to build a model for analysis of two gases entering a room and after mixing/diffusion in room the concentration is to find. there should be two inlet conditions for two gases and...
View ArticleCreating and using external Matlab functions
Does anyone have any experience in creating and using external Matlab functions? I am running Comsol 4.0a, and would like to be able to pass parameters to a Matlab function, do some calculations, pass...
View ArticleComsol 4.2a, RF MODULE, Mie Scattering
Hello Fellows, Can anyone send me .pdf file about Mie Scattering module, or .mph file but for 4.2a version.? I have to learn about scattering and absorption cross section, so i think it can be very...
View Article[Solved] Selection Left Click
Hello community, I am faced with a strange problem. I just updated to Comsol 4.3 after using 4.2a for a long time. But it seems I can't left-click on an object to select it anymore. I don't know...
View ArticleUrgent : Boundary layer meshing problem
Hi, I need a help to understand the boundary layer meshing in COMSOL. I have an axisymmetric model of a simple cylinder of diameter radius 6 mm. For the penetration depth of 0.14 mm at the outside...
View ArticleHow to define a dispersive material as a function of COMSOL predefined...
Hi: I defined a dispersive material function (frequency dependent relative permittivity) in Global Definition. Function name: LD_real Expression: ff E-14+0.6 Argument: ff Argument unit: Hz Function...
View ArticleModel saved in 4.2 need to be saved in 4.1
hi friends! i am trying a model of air and hydrogen mixing phenomena. i was using version 4.2 now i am using 4.1. The model i have, is saved in 4.2 i need it to be saved in 4.1 so that i can run it ....
View ArticleBoundary current source vs electric potential source
Hello, I have a question about the AC/DC module -> Electric currents. I made a simple model of a spherical homogenous volume conductor. Inside this sphere I added a cylinder along the 3-axes. On the...
View ArticleHow can I get the field distribution after the incident wave is subtracted?
Hello! I have a question need your help. I calculate a grating model in comsol4.3, and is illuminated at normal incidence with a TM-polarized plane wave. There question is how can I get the...
View ArticleBest way to switch on fields in time-dependent simulations
Hi, Is there a kind of recommendable way of switching on fields in transient emw-simulations. Right now, I'm using the step-function, included in Comsol, and I have some problems with the converge of...
View ArticleNegative port impedance
Hi All, I am currently doing some antenna modeling. The antenna is excited by a 50 Ohm coaxial port. I get reasonable S11 results at resonance but the lumped port impedance is negative e.g. -5 Ohms....
View Article3D Natural Convection Hot Plate
Dear all, I am having trouble with modeling natural convection for a while. I have started with a very simple case of having a hot plate at 150 degC surrounded by room temperature air and want to...
View ArticleBias Current Density
hi!! I need to generate 1.5 Tesla magnetic flux out of a rectangular block. what value of current density (J) should i use? what is the constitutive relation to find the required current density...
View ArticleMeshing errors
I just stated using COMSOL and I'm trying to build two helical coils stacked on top of each other with a ~5cm gap. Whenever I attempt to build the mesh I get the error tree, failed to generate mesh for...
View ArticleWhat kind of strain or stress should I be reading in the results for...
Hi, I am doing a piezoelectric simulation and using a force, I have displaced the piezoelectric cantilever. However, in the results section, I'm not sure which type of strain should I be looking at as...
View Articleadiabatic air compression
Hi, I want to ask what kind of modules I need to realize adiabatic air compression. I am not sure weather I need to define compression heat using ideal gas law or some modules can consider compression...
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...
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