COMSOL solver control
Hi, I am looking at a problem that solves physics at two different time scales. Basically, I want to do the following At a coarser time scale I want to solve a few partial differential equations...
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 ArticleDifficulty in using iterative method for Rf problems which has multiple ports...
Hi everybody, have anybody encountered the problem of keep on having ill conditioned preconditioner when you apply a lot of port condition on a single boundary (For grating structure simulations where...
View ArticleSolving For Total Field with Incoming Plane Wave
I am trying to find the total field for the a substrate with an incident plane wave (i.e. sunlight on a substrate). So far I have made an injection port with a plane wave, but the problem is that I get...
View ArticleNo convergence. Relative timestep too small. Double dogleg solver.
Hello, I am trying to use Double Dogleg Solver for a Navier-Stokes problem, and even tough the residuals in the convergence plot have reach 100% for the velocity and pressure segregated step, I get the...
View ArticleShape not in interpolation curve not preserved
I'm using an interpolation curve as a way to import a 2D geometry into my model. Figure1 shows the shape of the data I wish to import (as shown in Excel). However when I import this data, saved as a...
View ArticleGeometry optimization
Hello everyone, I´m modeling a simple heat transfer - structural problem, wher I have a 2-D rectangle with a hole in the midle. First I apply a Temperature load that produces expansion in the...
View ArticleCalculation of electrostatic forces
Dear all, I have a querry regarding electrostatic force calculations in comsol 3.5(a). According to the manuals and few tutorials on calculation of electrostatic forces in MEMS module, it seems to me...
View ArticleExtracting element data from higher-order tet-elements using MatLAB LiveLink
Is it possible to extract the specific nodes related to each tet10 element when using second order shape-functions within the MatLAB environment. I'm looking for a function similar to...
View Articlesurface integration (doing calculations with derived values)
Hello, I have a simulation with several subdomains. In the postprocessing, I'd like to relate two of those subdomains, i.e. I want to compare the power flow of say domain 1 to the power flow of domain...
View ArticleOptical waveguide 3d
Hi, I'm trying to model the modes in a waveguide at optical frequencies. The waveguide as a core (with slightly higher refractive index) and cladding a bit like a square optical fiber. I have adapted...
View ArticleSinusoidal Stress Time Dependent Study
I have been attempting to model a simple 5mm cube fixed on one side and with a sinusoidal time dependent stress on the opposite side. This should produce a propagating shear wave. I want to do this in...
View ArticleEstimated error in the energy norm OR the error norm.
Hello everyone, I am having trouble with something that I can't seem to find any help about in COMSOL support. I only see it mentioned very little and not in very much detail in the help documents. I...
View ArticleHow do you know which resonant frequency of the cantilever is the proper one?
Hi, everyone. I'm quite confused. It's a rectangular beam,with one end fixed. Then I do the eigenfrequency study. When I apply different mesh method to the beam, for example, first I use Free...
View ArticleMeshing Error
I am trying to mesh a geometry with 2 concentric cylinders present in a air flow passage for thermal study. While meshing.. i am getting the following error "intersecting face elements" for the inner...
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 ArticlePoroelastic waves - acoustic module - material definition
Hi, I would like to model a poroelastic material with the acoustic module. However, can you tell me how I can link my parameters to material proporties. My parameters are : - porosity - tortuosity -...
View ArticleNewbie needs help seting up ramp function as voltage source
I am new to comsol and cannot figure out how to assign a rect function as the input source to a strip of copper. I subsequently need to study the thermodynamics (which I have successfully done in...
View ArticleVery strange displacement values for eigenfrequency calculation of...
I am modelling a piezoelectric cantilever beam using the piezoelectric devices module in 4.2a. For certain beams, which have several piezoelectric elements on one beam, I get a very high value for the...
View ArticleTemperature Depdendent Electrical Conductivity acting weird.
Hi Everyone, I have two simple questions that I have been unable to answer after trying to work on them for a week. Please help me: 1) I have a very simple model (which I have attached), I am passing a...
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