PDE
I am currently working on COMSOL 4.0a. Can anybody tell me how the variables for stress are defined in COMSOL? Since I want to define a Coefficient PDE, which its diffusion coefficient (c) is coupled...
View ArticleCoupling Stationary study -> Time dependent does not work
Dear all, I have a very simple model (attached): a 2D model where I impose an initial strain, that generates stress. This stress will be relaxed by creep. The stress caused by imposed strain is...
View ArticleMeshing 2-D and 3-D geometries with matching meshes
Hi! I have a very expensive 3-D electro-chemistry problem which I am trying to simplify. The problem has fluid flow and electro-chemistry (tertiary current distribution) equations in it. I would like...
View ArticleEigenfrequencies of a spring WITH Gravity
In the real world, I have a flat steel beam that is acting as a spring. It starts out curved into a semicircular shape, and then it is loaded with a hanging weight that brings it down flat. I want to...
View ArticleTime dependent study on a 3D multiturn coil inside of an electrical circuit
Hello, I am trying to model the voltage in function of time across a 3D multiturn coil inside of an electrical circuit. To do this I use the Magnetic Fields and the Electrical Circuit physics and a...
View Articlefinite element method
What COMSOL product is useful in solving a system of coupled (linear) differential equations by the finite element method? Thanks!
View ArticleMWP combined with DC
Dear Daniel, I am geting tired of comsoling... because I do not know anymore what I can do to make my models converge. i started with the waveguide microwave plasma from the model-library. I put some...
View Articlehorizontal stress only shows in the top layer
hi i'm simulating a road using the elastic model. the road has 3 layers (asphalt, foundation, soil) with different moduli. when I apply the loads of the wheels, I can clearly see how the vertical...
View ArticleStore part of solution for next run
Hi: I have 2D and 3D models of the same experiment which are in the same file. I would like to do two things: 1) Store the solution of the 3D run and store seperately the data from a "cutplane". 2) Use...
View ArticleModel 4.3 vs 4.3b not converging
Hi folks! I've just updated from 4.3 to 4.3b and I'm trying to get some convergence but to no avail. I'm using the Mixture Model with the Schiller-Naumann slip model for settling suspensions. I get...
View ArticleViscoplasticity: stationary and transient modeling
Hi! I am trying to work on a model that has both viscoplasticity (Anand model from the Nonlinear Structural Materials Module) and contact. First, it seems like I'm having penetration. A stationary...
View ArticleAccessing prior solutions while solving a Time-Dependent Study
I am trying to create a condition for my bioheat transfer simulations that will deactivate blood perfusion effects when the maximum temperature (at any previous time point) exceeds 60 degrees Celsius....
View ArticleWill the increase of the relative tolerance reduce the solving time ?
Dear all, as mentioned in the title, I would know if the change (specifically an increase) of the relative tolerance in Time Dependent solver (but also in Stationary solver, why not) will reduce the...
View ArticleNanoparticle Growth
I have started working on nanoparticle growth kinetics and nucleation of the metal atoms. This is my first experience with COMSOL. I want to know how to start things off. Even a simple model is fine. I...
View ArticleProblem with Neumann boundary condition definition
Hi, I am simulating a Helmholtz equation (using the PDE mode module) with a Neumann boundary condition. Some days ago, we decided to update our Comsol version from 3.4 to 4.0. In the new version we...
View ArticleNernst-Planck equation
Hey everyone, I am new in using the Comsol software (4.1). I want to model ionic behavior in a conical nanopore and need to solve the Nernst-Planck, Poisson and Navier Stokes equations. However I need...
View ArticleTransport of diluted species and electrostatics
Dear Community, I am trying to combine the physics of the poisson equation (electrostatics) with the nernst-planck (transport of diluted species) in Comsol 4.1 for like 6 weeks now, and all I get is...
View ArticleAxisymmetric Hertzian Contact mechanics model
Hi, I am trying to model a sphere pushing on a surface. To do so, I have created a 2D axisymmetric model with a point load close to the apex of the half-circle; as putting a point load right at the...
View ArticleTrouble coupling heat transfer physics for both fluids and solids
Hey all, So I'm getting stuck with my model where I try to couple three different physics. The three physics are: Electric Currents, Heat transfer in Solids, and Heat transfer in Fluids. Basically what...
View Article3D Model of "Voltage Induced in a Coil by a Moving Magnet"
Hi I wanted to do the 3D version of the Model "Voltage Induced in a Coil by a Moving Magnet" which is in the Comsol Library. I used the same physics, materials and boundary conditions, but...
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