Initial negative concentrations
HI All, I am trying to simulate a A+B-->C chemical reaction. I dont know why my reactants (A and B) concentration is going negative. How do I fix this? I have attached my model as well as pic of the...
View ArticleError in swept of a mapped/quad mesh
Dear all, I am getting a problem in the meshing of a multilayer, composed of 3 very thin layers (0.3, 0.01, 0.04 mm). I want to mesh them using a mapped mesh, and then swept (using one swept for all...
View ArticlePML Error: Could not find any cartesian regions
Hi I am new to PML. I am using Structural mechanics module to implement PML in a cantliver to determine the waves propagating to the PML. I am getting this error: Could not find any cartesian regions....
View ArticleHow to set boundary conditions?
I'm new to COMSOL. Where can I find the options for setting up boundary conditions for a model? I need scattering boundary.
View Articledefining output variable of an interface as dependent variable in global...
I am trying to simulate surface deformation due to magnetic field. My model consists of a cylinder filled with conductive fluid surrounded by a single coil (approximated by a line element). I coupled...
View ArticleTwo-phase flow physics
Hi there, I have experience dealing with CFD problems with the finite volume method. I use my own code, starccm+ and openFOAM very often. I am trying to make some animations with a multiphase flow for...
View Articlemodeling of Diffusion
Hi, I want to model a simple mass diffusion process, but with a concentration dependent diffusion coefficient. In variable I defined a function for diffusion coefficient. but when I want to solve the...
View ArticleMeshing problem for coaxial cable with helical inner conductor
Hi Good day. I am using a coaxial geometry which has helical inner conductor and cylindrical outer conductor. I am also using emw physics.while simulating/mesh generating I am getting error which...
View Articlevertical exaggeration
Hi all, I'm trying to change the views of my 2D plot in order to have a vertical exaggeration (1:4). I've tried to play with the lock aspect ratio but it seems the model is squeezed into a cube-like...
View ArticlePrescribe number of Meshing Elements
Good day, for a model of simple geometry (sphere) and fixed volume, is there a way to define a specific number of meshing elements? I am trying to solve my system with a specific number of elements and...
View Articleelectrohydrodynamic problem
Hi all, I'm currently simulating the electromechanical effects of water droplets under both AC and DC voltages. The water droplet is placed between an energized and grounded electrode on an insulating...
View ArticleGeneration of thicker boundary layer mesh
Hello guys I wanna make some think boundary layer meshes. In my simulation, the boundary layer thickness delta is so big in that Re_x = 9.8 and delta = 5.0x/sqrt(Re_x). So I think the boundary layer...
View ArticleCreep - Plasticity
I want to use the non-linear structural mechanics module for simulation of plastic deformation by yielding. There is a creep module and a plasticity module. In the creep module, I find more suitable...
View Articleimport particle positions in Particle Tracking
Is it possible to import particle positions in COMSOL for particle tracking? If not, can you add one, please?
View Articlewhat does the "exclude algebraic" error estimation option do?
I'm working on a time dependent convection-diffusion simulation. The Peclet number is 10^3 to 10^4. The maximum Reynolds number is ~100. The solution tends to diverge at a point where the input...
View ArticleMagnetic Force on an armature
Hello I'm dealing with a very simple problem that has been very frustrating for me! I would appreciate if any one can assist me with that. I'm modeling an E-shaped core in 2D magnetic field module. It...
View ArticleLarge Eddy Simulation
hello I want to use Large Eddy Simulation on comsol but I can't found it. Can you help how to do this. thanks a lot
View ArticleBase vector coordinate system
I am modeling the anisotropic behavior of a plate that have fibers oriented in different directions. For this purpose, I am using the structural mechanics feature. I am orienting my fibers using a...
View Articlehow to do moving mesh in 4.2a
Hello everyone I am implementing a rectangular piezoelectric converter, in which i want to be vary the length and width of the piezo layer via moving mesh ale. I studied one of the paper of "Thickness...
View Articleexport mesh data for an explicit selection
Dear all, I am a relatively new user COMSOL with a lot of Finite Element experience both on the programming and theory level. I started with COMSOL today which went actually quite fine and fast. I...
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