initial value set-up
Hi, I have a 2D simulation running from T=0 to T=100. First, I run the simulation from T=0 to T= 50. Then I want to use the solution at T=50 plus some value changes in specific domain as the initial...
View Articleself-intersection
Dear all, I'm trying to mesh a more or less complex structure and right now, I always receive the error message that self-intersection is not supported. Can anyone explain this error message nearer to...
View ArticleFinding a mapping of Current Density (variable J) using the Electrostatics...
Hi everyone, I'm making a model using the Electrostatics Interface from within the limited AC/DC Module included with the base COMSOL Multiphysics package. Initially, I tried making my model using the...
View ArticleMagnetic field
Hello I created a simple model where the magnetic field and electric wire. 1 Why not spread outside the magnetic induction coil? 2 Why is not moving conductor in a magnetic field? What I made a...
View Articlecomputing accurate fluxes with periodic boundary conditions?
Hi everybody, does anyone know if I can compute the fluxes accurately, as described in the user guide on page 308 ff. and file 0973 from the knowdledge database etc, when using periodic boundary...
View ArticleElectrostatics vs Electric Currents Interfaces. Something is wrong...
Hi everyone, I mentioned this in an earlier post. I believe I have an inconsistency with the software (COMSOL Multiphysics Base Package). This may or may not be intended. When picking between the...
View Article3D Poisson equation problem coupled with Nernst-Planck equation
I used coupled Electrostatics physics and Transport of Diluted Species physics to simulate this problem. The source term in Poisson equation is the difference between cations and anions. Usually, the...
View ArticleSubsonic Ramjet Model
I am attempting to optimize the design of a ramjet to be created for rocket experimentation. I have been working on the model for the fall semester attempting to refine it. I am now using a 2d axis...
View ArticleLow Reynolds Turbulent Flow
Hi folks, does anyone know what the "spf.wall_spf" variable means in the AKN Low Reynolds k-ep model. I can see it in the equation view, but other than that, there is no more info... I am really trying...
View Articlebubbly flow: udrift in laminar flow...
Hi, I am currently working with the bubbly flow application mode in a laminar flow. The gaz velocity, ug, is computed thanks: ug=ug+uslip+udrift In the help, is it said that the drift velocity is...
View ArticleEffect of sound pressure on refractive index/density
Hello fellow Comsol users, Most of my experience comes from structural mechanics and fracture and would like to ask a little help regarding pressure acoustics. The presence of high and low pressure in...
View ArticleAssigning Materials
While assigning materials to some solids in my model, I am getting a red cross below the material name in Model Builder. What does that mean? What changes should I do to use those materials for the...
View ArticlePDE General Module for Stefan-Maxwell diffusion
Dear User's I am trying to perform a run at PDE general module and having some issues when i input the Flux vectors. Can anyone tell me how the form of such vectors should be?? Thank you very much
View ArticleSimulationtime for mapped meshes in 2D and 3D
Hi, Normally I used triangular meshes to simulate thin films on cantilever beams. Because of the very high aspect ratios I 've tried to use a mapped mesh for the rectangular geometry. The amount of...
View ArticleCooling after Inductive Heating of a Copper Cylinder (from Model ID: 148)
Hello, I am a new Comsol user. I have been trying to observe the cooling of the copper cylinder in the model 148, after a short period of heating. I tried to adapt the Icoil variable at the Single-Turn...
View ArticleManipulating data from tables
Hi all, I'm working on a model using piezodevice physics in the frequency domain, and I'm trying to plot admittance in dB (rather than siemen). I've found the admittance by taking the surface integral...
View ArticleALE question
Hi, I'm interested in the transient effects of a moving charged object on a grounded one (see image). I have first modelled this using a parametric sweep on the object's x position. But of course, this...
View ArticleGeneralized alpha time dependent solver
Hi, if I switch from BDF to the generalized alpha time dependent solver the solver works with a timestep of 0 or near zero. I can set a manual time step and the solver calculates the time correctly,...
View ArticleStraw Poll: Who would like to see the model gallery documentation overhauled???
Hello all, I thought I'd post this here to get the community opinions before suggesting it to support. If I want to learn how to use an aspect of Comsol I work through example models and I visit the...
View ArticleUsing step function in kinetic reaction simulation
Hi I am trying to simulate the kinetic reaction of biomolecule interaction in fludic channel expecting to have association and dissociation phase (concentration of complex versus time) in the same...
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