Surface evaporation, condensation
Hi, I want to model surface evaporation from a water flow at 40 Celsius and observe the consequent condensation on a cold surface. Can you help me with the model that I should use? I could not find...
View ArticleUsing the results of iteration as input to next iteration?
I am using Comsol to calculate cooling in oil-paper isolation. The iteration is slow and does not converge easily. I have reduced the damping factor to achieve a reasonable solution. It would be fine...
View ArticleURGENT!!ERROR
Hi!during the simulation an error appears: Failed to find a solution: In segregated group 1: The relative error (0) is greater than the relative tolerance. Returned solution has not converged. What...
View Articleerror MEMS
Hi Ivan sorry if I am contacting you but I need help. I have problems with the attached exercise. The error that appears is"Failed to find a solution: In segregated group 1: The relative residual (0)...
View ArticleInternal and external natural convection seperation
Hello COMSOL Community, Firstly I would like to say thanks to everyone who so regularly contributes to these forums and breathes life into them; namely Ivar. I have been setting up a relatively complex...
View ArticleAverage velocity profile
Hello everyone, I simulated fluid flow in a medium composed of porous matrix overlaid by a channel (attached figure). I am going to plot the average velocity profile along the length to examine the...
View ArticleForced external convective cooling
I have what must be a stupid question about cooling by external forced convection. I'm trying to model a metallic object that is locally heated on one surface and that will be cooled on the other...
View ArticleMatrix has zero on diagonal
Hi experts, I mat a problem when simulate a AC/DC model. it came out as below: Failed to find a solution for the initial parameter. Segregated group1 Matrix has zero on diagonal. Returned solution is...
View ArticleNACA 0012 Airfoil with Spalart-Allmaras turbulence model
Hello, I am new to COMSOL and I thought I would start with a relatively simple model: a NACA 0012 airfoil at 0 angle of attack. The domain is small and the mesh resolution is relatively coarse to get...
View ArticleSurface evaporation, condensation
Hi, I want to model surface evaporation from a water flow at 40 Celsius and observe the consequent condensation on a cold surface. Can you help me with the model that I should use? I could not find...
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 ArticleMeshing Air
I'm new to 3D COMSOL and I have the geometry for a chamber that will have air running through it while it performs its function. I am easily able to mesh the geometry, but I'm having problems finding a...
View ArticleCreate Probing Surface then Surface Integrate over it
Good evening Ladies and Gentlemen! I'm working with a 3D fluid flow model, and I want to find the mass flow rate through an arbitrary cross section of the flow. How can I create a surface that can then...
View ArticleSolving a 4th order PDE: how to specify boundary conditions
A fourth order PDE like the biharmonic equation: ∇^4 w = 0 can be placed in Comsol's standard forms by writing u = ∇^2 w, so that we have system of equations:∇^2 v = w∇^2 w = 0 where v = v(x,y) and w =...
View ArticleHow can I simulate this problem??
I'm new to COMSOL, I want to simulate multiphysics(flow rate and electric field) but have some problem about meshing geometry. I use ITO electrode and water contain in the microchannel. ITO thickness...
View ArticleFind Cross Sectional area perpendicular to an axis at every point
I have a variable diameter hose and I want to find the mass flow through this hose at every point. There are no bends in the hose except to change its diameter so the hose's central axis is in a...
View ArticleTotal Mass and Mass Flow Rate discrepencies
I have a pipe that flows air through a porous media. I calculated the mass flow rate by doing a surface integral across my inlet and outlet. I put fp.rho*v in the integral expression box (where v is...
View ArticleConvergence problems with non-newtonian power law fluid
Hi, I'm modeling fluid flow through a microfluidic bifurcating network. Among other things, I am calculating the volumetric flow rate for a given applied pressure and comparing it to experiment. The...
View Articleflow boundary conditions: periodic velocity fall and normal velocity zero
Hello, I am attempting to simulate a 2D flow of a suspension of solid disks on a square lattice. To reduce the computational expense of this simulation, I'd like to consider shear on a single disk at...
View ArticleVariables
Hi everyone, I have a simple question for you. If I have a variable 'D' , coeficient difusion, depends to temperature (T) with the expression D(T)=0.29*T. the range of temperature is (900 kelvin to...
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