Isolating components in study steps (and solutions)
Can someone help me understand why even though I tell all my study steps under one study to use only a single physics interface the solver still tries to find dependent values for variables under the...
View ArticleMass flow rate vs temperature.
Hi, I used Comsol to model a really simple problem. A pipe with 50mm diameter and 25m long with an inlet temperature of 20°C and 0.5kg/s of mass flow rate. Also, the pipe´s wall temperature was 150°C....
View ArticleOptimisation of processing parameters in laser sintering of metal/alloy powders
Hi everyone, I am new to COMSOL Multiphysics.. Can anyone help me in simulating selective laser melting(SLM)/direct metal laser sintering(DMLS) of metal/alloy powder media in layer-by-layer fashion? IN...
View ArticleLimiting the Parametric Sweep study step to a specific step(s) in the study.
I'm doing a small signal analysis (stationary, freq-perturbation) and I want to run a parametric sweep (on geometry) for the stationary step only. I can't seem to figure out how to isolate this within...
View ArticleRotation of 3D geometry taking too long time to compute
I am using the rotating machinery laminar flow physics. I am trying to solve with time dependent study. Every time after computing 7% or 4% it hangs up and continues doing iterations upto 2000 and...
View ArticleSimple structural mechanics model does not converge
Hi, unfortunately I can't find the reason, why my simple mechanical model does not converge. Can someone help? Thank you. Kind regards, Levin
View ArticleImplementing functions into COMSOL
I've (very) recently started working with COMSOL with the aim of implementing "extern" formulas for certain equations into COMSOL using different models. For that I need to know how to define any...
View ArticleHow to vary the magnetic field?
Dear All, In Wave Optics ----> Electromagnetic Waves I wish to study the effective refractive index variation w.r.t. variation of the magnetic field. Here, I need to know how to vary the magnetic...
View ArticleWarning: a third set of iterations may be needed
Hello everybody, When I am performing a study with the segregated solver (with 2 segregated steps), I encountered in the log file and after a few iterations (generally 3) this warning "Warning a third...
View Article3D modelling of ICP torch
Hello! I'm trying to modelling 3d ICP torch. But i have problem with Magnetic Field. I don't understand how can choose input power? I see only current and voltage.Also, what is the difference between...
View ArticleFailed to find a solution. System matrix is zero. Returned solution is not...
I am trying to solve 2 coupled ODEs and am using the coefficient form PDE module to solve it. I have zeroed out the coefficients of the terms with time derivative. Btw this is a 1D problem where the...
View ArticleHeat transfer problem - Wrong Solution due to Heat flux boundary condition...
I'm doing a simulation of a channel flow with thick walls to understand the differences between macro scale and micro scale effects. When I impose an heat flux boundary condition with a certain value,...
View ArticleConvergence problem while simulating a degaussing process
Hello, I'm currently running 3-D simulations of ferromagnetic materials that are being degaussed. When I use the "Magnetic Fields" node it works quite well, however, then everything depends on the...
View ArticleSolid and Fluid motion with eigenfrequency study
Hello, I made a very simple geometry in 2D, such as the cross-section of a microcapillary. I want to find some eigenfrequency which can make a few modes on a microcapillary. So, for the shell I used...
View ArticleConvergence problems/solver tuning in simulation of instationary journal bearing
Dear COMSOL Community, In a instationary journal bearing simulation I want to evaluate the resulting stresses in the bearing shell. Therefore i solve the reynolds equation on the journal bearing...
View ArticleInitial Values setting during parametric sweep calculation
Hi all, When I was doing parametric sweep in a stationary solver, I found that once the "stationary solver" is started, the initial value for every parametric step is defined by solution of the last...
View Articleoptimization of a time-dependent problem
Hi everybody, can you indicate me a Comsol doc or a Comsol tutorial paper in which i can find an approach to solve time-dependent optimization problems? The fact is that I need to know if it is...
View ArticleModel convergence issue
Hello everyone I am conducting a time dependent study. My model converges for smaller time scales viz range(10^-12,10^-6,1.1354e-5) . However, when I run the study for a larger range, which is...
View ArticleRestore model
Hi My computer shut down itself and I had not saved changes to my model. Could anybody guide me how can I restore my unsaved model? Appreciate the help Thank you Best regards
View ArticlePlotting Probe Measurements
Hello All, This seems like it should be a simple answer, but I'm having trouble. I have a permeability model set up using Darcy's Law. I have a transient step function to change pressures throughout...
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