Convergence problem with system of pde's: compressible flow + pde for density
Hi, Here is the problem: I am solving these equations having a periodic boundary conditions in a square. At the top and bottom of the square the constant velocity v0 and pressure p0 is applied. It is a...
View ArticleError simulating fluid flow through microsieve
Hi everyone, I'm newbie to COMSOL Multiphysics. I'm trying to anticipate when a microsieve is broken under fluid flow (blood filtering), but some errors keep occuring. Please help me! Thanks very much!...
View Articleone step vs. parametric sweep convergence
Good morning, My solid mechanics model is basically a needle (modeled as a 3D solid not a beam) which is fixed at one side and laying over a box at the other side. When the box is moved upward the...
View ArticleHelp with "Nonlinear solver did not converge"
Good day everyone! I am working on a multiphysics problem involving reaction engineering, thermal stress, fluid flow in porous media, and species transport in porous media. At a certain timestep, I...
View ArticleI have two models, model 1 and model 2. When solving model 2, the initial...
I have a question. I have two models, model 1 and model 2. When solving model 2, the initial value of model 2 is the result of model 1. should I set it ? special information as follows: (1) Model 1 and...
View Articlefailed to find a solution when coupling heat transfer with fluids dynamic!!
Hi everyone I'm trying to model a transformer using multiphysic (thermal, fluid dynamic) modeling on Comsol. when using only the thermal modeling, (only using heat transfer physics) the program is...
View ArticleFrequency Dependent Permitivity.
HI Comsol Users I am trying to model the e-filed lines expected for a PbTiO3 crystal with electrodes on top and bottom to which I apply a voltage to the top one and leave the bottom one grounded.. I...
View Article3D SPF Convergence Issues
Hello, I'm working on a 3D model in an attempt to simulate water waves in a tank generated by a sinusoidal pressure source. I've been able to create an otherwise equivalent 2D model which works, and...
View ArticleExtremely high local stress maxima in static analyses
Hi, i'm experiencing a problem with a quite simple static analysis in comsol multiphysics. In attachement 1 you can see the geometry of the model, which consists of two plates (aluminium) that are only...
View ArticleMoving mesh plus automatic remeshing
Hi, I want to simulate a cavity that moves into a solid with a specified velocity in a transient simulation. When the mesh quality becomes too low, I want to use the automatic remeshing feature....
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Coupling problem: Nernst-Planck equation with Poisson not converging
Hi, I am unsuccessfully trying to implement to Poisson equation through the Electrostatic Module into the Module "Transport of Diluted species" for a stationary case. Beside those modules I use the...
View ArticleError message: Failed to evaluate expression. Failed to evaluate operator....
Hi people I have been encountering this error message: Failed to evaluate expression. - Expression:...
View Articlecomsol error Failed to evaluate variable.
I have this error, see the attached file. Can any one help me quickly, please ? Thanks.
View Articlecluster computing
Hello, Can anyone help me figure out these errors andor how to run a very large model on multiple nodes? I am having a terrible time trying to run a very large model on multiple nodes on our cluster. I...
View Articlebaffled duct - PML 3D PROBLEM
Hello every one, I’d like to excite a cylindrical waveguide (rigid in one face and flanged in the other one) with a monopole located in M(x,y,z) and compute the pressure inside the duct. Also, compute...
View ArticleSolver Configuration for Nonlinear Highly Coupled Fluid Flow Chemical...
Good Evening, I've been working with Comsol for the last four months trying to model a system using the Free and Porous Media Flow module coupled with the Concentrated Species module (along with the...
View ArticleWork on COMSOL through MATLAB?
Hi, I would like to run COMSOL through MATLAB but don't understand how? For example when I have saved a COMSOL simulation as M-file and tries to open it in MATLAB it won't open and I am not sure how to...
View ArticleProblem in one of the Model Library of Comsol 3.5
Hey guys, I'm currently trying the model 'Two Phase Fluid-Structure Interaction' in V3.5's Model Library. You can find this at Model Library-> MEMS Module-> Microfluidics Models->twophase fsi....
View ArticleParametric Sweeping a Geometrical Parameter! Possible?
I have a polymer coil in a solid cylinder. This is a reaction-diffusion model. I think usually the materials property or other similar non-geometrical properties are sweeped in parameter sweep. I want...
View Articleproblem in comsol program
Hi comsolers, I defined two projects in comsol in 2D for solving richards equation: first project: simple rectangle that left boundary was defined as pressure head=0.8 and right boundary as pressure...
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