Hagen–Poiseuille flow
I would like to use Comsol for a microfluidics project I'm working on. As this is my first time working with Comsol I am trying to simulate a simple problem to compare the simulation with analytical...
View ArticleCFD - Surface roughness
Hey guys I really need your help on this one! I was wondering if any of you could tell me about the default settings of surface roughness's in COMSOL? All I've found about it in the documentation is...
View ArticleSpecifying a rotating boundary condition
I would like to simulate a rotating wall condition. For simplicity, imagine a square box. On the top surface of that box there is a circle. Inside of the box is a viscous fluid. I would like to impose...
View ArticleAssigning Materials to the solids in model developed
Sir, I was trying to assign material to the solids in the model. I am facing difficulties in assigning materials as the model kept on changing different colours and I am not sure whether my selection...
View ArticleNon - Isothermal Flow (nitf)
Sir, I have assigned materials to the domain elements that are required. And, in the step of inspecting the physics part after assigning materials, it is again asking for domain selection. What does...
View ArticleWhich solver type to use for coupled K-Epsilon and pipe flow model?
I have a heat exchanger model that I am solving with the CFD and pipe flow modules. I am unsure of which type of solver I should use. I have looked at the COMSOL example model 'heat exchanger plate'...
View ArticleFree & Porous Fluid Flow -- Measure of mass flux
Hi All, I am attempting to model a stream bottom seepage collection device, but I getting some strange results. I am starting out fairly simple with no lateral flow in the free fluid, and setting the...
View ArticleUsing strain rate as a variable
Hi All, I am using COMSOL 4.2 to simulate plastic deformation of aluminum via a dynamic-viscosity approximation. The approximation requires strain rate. My question is how do I access strain rate for...
View ArticleMeshing Internal Volume of CAD import
All, I am trying to model fluid flow inside of a CAD object. How do I create a domain inside the object that I can mesh? I have capped all the openings. Thanks, John
View ArticleProblem with meshing
Sir, While meshing my model, I am getting an error message as follows "Out of memory for mesh processing". What does that error mean and what are the correction requirements??
View ArticleDubinin Sorption Model on Dual Porosity System
Hope this message finds you all well. I have a little technical question. I am currently trying to build a dual porosity model using the earth science module of comsol multiphysics 3.5a. However, I...
View ArticleTry converting to triangular mesh on these faces
Dear sir, While meshing my model, only one domain didn't get meshed. And the error shown for a face which is not meshed is "Try converting to triangular mesh on these faces". And, I was not able to...
View ArticleProblem with periodic boundary condtion.
I am trying to implement the advection equation with periodic boundary conditions using DG. I have specified homogenous Neumann flux on all the boundaries and then I have used the periodic condition on...
View ArticleRandom nucleation
Dear all, I am currently involved in a phase change simulation. I have not yet found the way to deal with random nucleation occurring for instance during the quenching : during the transient heat...
View ArticleSharp Fluid-Fluid Interface
I’m new to COMSOL, and I was hoping someone here would be able to help me. I am trying to model fluid displacement in a pipe. I could use the two-phase flow module, but I don’t need that level of...
View ArticleWhat Physics I need for a liquid cooling problem with phase change
Dear everyone, I am totally new to COMSOL. Now I am working on simulation of a cooling system. It is a melted material thrown to another liquid (e.g. water). This may cause phase change of water from...
View ArticleModifying the Fluid Flow Equation System
Hi everybody, Is it possible to change the fluid flow equation system in order to fit a logarithmic function in the derivative? I am currently using the earth science module to model a dual porosity...
View ArticleHelp solving nonlinear 1D diffusion equation
Hi All, I need to solve the following 1D diffusion equation on domain x=[0,0.4] between time t=[0,2]: w(u) du/dt = d^2u/dx^2 where w(u) = 1+184/u*(-1/log(u))^(4/3) subject to the initial condition...
View Articlebuilding a multicomponent gas mixture in comsol
Hello All, I was wondering if someone could help me with building a multi-component gas mixture in COMSOL 4.2. I have my biogas composition of 66% CH4, 33% CO2 and 2% H2S and I need to define...
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