Simple example to solve ODE
Hi, I am a complete newbie with COMSOL (I have the MultiPhysics module, version 4.3a), and I have only followed some initial tutorial examples in the manual (e.g. "the wrench"). However, as I...
View ArticleInitial 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 Articleobject in a magnetic field
Hi, I'm working on a similar problem as yours. I'm currently making a model on Comsol which calculates how the angular rate of an object in a magnetic field decreases over time. What I did, I put an...
View Articlecoupling solid mechanics with magnetic fields
Hello, I'm currently trying to analyze the change of magnetic flux that is made by a 3D magnet that is adjusted on a periodically moving beam. (Physics: SOLID, MF and Time Dependent) But unfortunately...
View ArticleShallow water waves model in coefficient PDE or general PDE
Dear All, I want to solve the Shallow water waves equation in PDE module in 2D. h is the water elevation. How can I implement an incoming pulse in the times domain from the left on the structure. If I...
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 ArticleParticle Selection
Hello, I running a simulation to release particle in an electric field and observe their tracks. I wish to find out how many particle and how fast they reach a certain boundary. I have been able to...
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 ArticleHow to use compressible gas flow .
Hi I am trying to find a module for doing the analysis of a gas flow in a little 2-d chamber where I am using a compressible gas at a predefined pressure from a tank ranging from 3-6 psi-g at the inlet...
View Articlehow to apply two phase voltage in an Piezo Divice
Hi, I modeled a piezo actuator driven by two phase voltage that one is 90-degree behind, that is sin(wt) and cos(wt). Now I'm doing a frequency domain study，BUT how could I applied the voltage? I've...
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...
View Articlewater hammer
hello to everyone well I'm a student and hydraulic master2 I presonte memory of my study is to fain ^ ^ analysis of a battering ram in a pipe under COMSOL aep ^ 10 next joure. I have download COMSOL...
View ArticleInterrupt studi
Hello. I am new to COMSOL and I want to ask how to interrupt study in some condition and change the parameters of the model? Thank you. Goodbye.
View ArticleTo solve electric double layer between parallel plate
Hi. I'm trying to solve electric double layer between charged parallel plate using Nernst-Planck eqn & Poisson eqn rather than Poisson-Boltzmann eqn. Because I want to research double layer overlap...
View ArticleHow to get a solution for EDL
Hi. I'm trying to solve the electric double layer structure using Nersnt-Planck eqn and Poisson eqn rather than Poisson-Boltzmann eqn. My domain is pallel plate of which height is nanometric, typically...
View ArticleError: Parameter lists gives empty sweep
Hello, I would like to know the reasoning behind this error in return of a monotonously incresing series of frequencies. Examples: a) 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90,...
View Articlerelation between two sudy
hi all, i created a model of piezoelectric device in piezoelectric module,now i want to transfer it to electromagnetic wave module because i need S parameters(that aren't in piezoelectric answers)but...
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 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 ArticleTwo interdependent studies - but I cannot use results from frequency domain...
Dear all, How can I use the result from a parametric (parameter 'b') sweep-frequency domain study (e.g. emw.Ez(b) ) in another function defined under Definitions (e.g. f(emw.Ez(b)) ) which is used as...
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