Setting initial values for an iterative solver
Comsol user interface shows some options for setting initial values at the stationary study step at 'Initial values of variables solved for'. These are either zero or a solution - but we want to set...
View Articletrack velocity of inflow fluid
Hi all, I have a tube which has an inlet to allow fluid to flows in. Would like to know, how can i track the velocity of inlet fluid flow when it flows inside the tube? By using particle tracking...
View ArticleAccess to a local stiffness matrix - possible modification of the gloobal...
Dear all, I´d like to kindly ask you if you could tell me, if there exists a way how to ge the access to the global stiffness matrix assembling process in order to make some modifications. I don´t want...
View ArticleDiffraction on an isolated line
hello everyone, I have a problem. now I want to simulate the diffraction for an isolated line, and I want to observe the intencity of different diffraction orders, both transmitted and reflected....
View ArticlePiezoelectric Eigenfrequency analysis - Decay factor - Understanding results
Hi, I carried out successfully an eigenfrequency analysis of a piezoelectric structure and now I need some help in understanding the meaning of the results. These are the six eigenfrequencies that I...
View Articleflux along -x
Hi all, I am doing simulation on waveguides (2D simulation, vertical section). I calculate the flux along a vertical line. I would like to control the flux along -x to see if there are some...
View Articlebeam vibration by a shaker
Hello, eneryone. I am doing a project simulating a simple beam structure vibrated by a shaker. The left end of the beam is fixed with the shaker. If I want to set the beam vibration acceleration at 10...
View ArticleHow to solve the problem of negative concentration
I am a totally new user on comsol. Now I try to simulate the mixing in the microchannel without reactions. I use the laminar flow and Transport of dilluted species. There is a similar example from...
View ArticleCoordinates in mapped system, expressions (X.Y.Z)
Hi there Im student, and working now on SAW Pressure sensor My PC have 4Gb RAM and I cant use 3D for this modeling. only 2D So, my surface material is ST cut Quartz, Euler Angles is (0;132.75;0),...
View ArticleNVIDIA driver 305.93 causing erratic behavior
COMSOL was working great until I got a Tesla NVIDIA GPU. After installing the driver NVIDIA 305.93 I started getting erratic behavior when mouse clicking on the graphics. When I click to highlight a...
View ArticleDiscussion Forum now Supports LaTeX Equations
Hi, We have just implemented the support of being able to communicate your mathematical equations using LaTeX formula entry. This is described in the 'Help' section, by clicking on the Help button or...
View ArticleFace and edge selection broken in 4.3/4.3a on NVidia/OpenGL
Continued from other thread:www.comsol.com/community/forums/general/thread/32259/ The other thread was marked as "Solved", but it's not solved (using software rendering is not a sufficient workaround),...
View ArticleThermal Conductivity as a function of temperature
Hi all, I am trying to include thermal conductivity as a function of temperature in my model but its giving me error 'inconsistent unit'..let us say the function is -1.27E-9*(T)^3+8.09E-6*(T)^2-...
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Area terms while using Axial Symmetry
Hello everyone, I have what I beleive to be a somewhat simple question. I would like to model simple heat convection out of a cylindrical wire or water pipe. It really doesn't matter what it is, just...
View ArticleOscillating boundary condition
Hi, How can we impose oscillating boundary condition in terms of velocity, on a boundary of a defined geometry. Thanks in advance Saurabh
View ArticleBoundary conditions in the tutorial model (Periodic boundary conditions)
Hi all, I have question regarding the boundary conditions used in the tutorial model about periodic boundary conditions. In this model a plane wave with a wave-vector with non-zero x- and z-component...
View ArticleWhy does COMSOL lead to zero solution for a high-order PDE?
Dear all, I'm trying to solve a system of PDE, where the highest order is 4. COMSOL supports finite elements of 5th order. So solving the equation system should be possible by using COMSOL. But the...
View Articlewhy my model works on Mac OS but not Win 7 64bit
I have a very funny situation in the coupling the fluid flow with moving mesh and transport of diluted species. It works very well with macbook air 2011 version but not with my HP PC workstation 8gb...
View ArticleHow to model adsorption on a solid surface for a 1d stationary model
Hello, I created a 1D, stationary model using the Diluted Species Interface to model the diffusion and reactivity of several species within a diffuse layer adjacent to an electrode surface. Now I am...
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