Modelling Continuity equation in COMSOL
Hi, I have a modified equation for the fluid continuity equation based on the perturbation expansion. The modified eqn is: d(rho_1)/dt + rho_0 * div (v_1) = 0 (also attached the eqn in the png...
View ArticleLimiting simulations-Dynamic Pull-in Cantilever
Hi everyone, I have a quick question, Can I tell comsol to simulate till it reaches some theoretical value and the stop? I mean, what I'm trying to do is Simulate the dynamic behaviour of a cantilever...
View ArticleEquation View of Heat Transfer
when the Physics "Heat Transfer" used, we can see such Variables in the Equation View: ht.kxx Thermal conductivity, xx component ht.kyx Thermal conductivity, yx component ht.kzx Thermal conductivity,...
View ArticleDefine a Mixed (cauthy) boundary condition for Richards Equation(subsurface...
I read some paper, in the old version of COMSOL, we can choose a Mixed boundary condition (mix of Dirichlet, Newman and Cauchy conditions). in order to automatically transfer the boundary condition...
View ArticleCreating a region with a constant gradient field
I want to create a region of air with a static magnetic field in the z direction that has a constant slope (gradient) in that direction as well, for example H(x,y,z)=(0,0,1+z/10). Once I have this, I'm...
View ArticleHow to get final dimensions i.e. outer profile in COMSOL?
Dear friends i want a help in this part. Here, i'm explaining the full problem. # i got the co ordinates of a biological part from image analysis in MATLAB . I plotted those points in the COMSOL (...
View ArticleUnable to create mesh : Error Free Tetrahedral 1
Hi everybody, I am having this error when I try to mesh a 3D structure : The following features have problems : Features : Free Tetrahedral 1 I don't find a way to have more information about this...
View ArticleEuler-Euler Model: reached singularity
I am running a Euler-Euler model and get a singularity error about six seconds into a 12 second analysis. It appears that there is a high velocity flair at an inlet when the singularity occurs. I have...
View ArticleStrain localization
Hi everybody, If I press a soft block of material with elastic modulus of 60 MPa with a hard sphere, when would I have the strain localization? Does buckling means strain localization or a sign of...
View ArticleBezier Curve equation
Hello, My model involves drawing a second order Bezier curve, and as part of it I have to be able to get the "Y" value on the curve for a certain "X" value. Normally that wouldn't be an issue because...
View Articlefunctionality of time-dependent adaption
Hello, I’m member of a research group at the University of Augsburg which is working on acoustic-wave-simulation in composite materials using COMSOL. Since the problems we solve are extremely...
View ArticlePotential Distribution in AC/DC Module, Comsol 4.3
Hey, i am working with the AC/DC Module in Comsol 4.3. I have a formula for the potential distribution (V) and I want to calculate the electric field by using the relation: E = - grad(V). Are there any...
View ArticleUsing a built in physics interface
Hi All, I have a modified equation for the fluid continuity equation based on the perturbation expansion. The modified eqn is: d(rho_1)/dt + rho_0 * div (v_1) = 0 (also attached the eqn in the png...
View ArticleThermal bridge
Hi, I study thermal bridge during my internship and I try to simulate basics thermal bridges like a training session. I'm blocked in a final analysis after modelling. I don't know what expression I...
View ArticleMemory Error
Hi everyone, When computing recently a 3D geometry with conjugate heat transfer module, I got this error:"Failed to find a solution. Out of memory during LU factorization. Returned solution is not...
View Article(backstep Time dependent problem)Failed to find consistent initial values....
Hello, I am using comsol 4.1, the model verification models in model library CFD Module --> verification models --> backstep. this model is steady study , and when I add a time dependent study...
View ArticleSimulatneous temperature distribution...!
Dear Comsol Users, I am willing to come over to you again, this time with some questions I would like to be enlighted. I've built a 3D heat exchanger (coil) inside a material (cylinder) and with...
View ArticleLink Matlab to Comsol in MAC - path problem
Dear all, in the bin/comsol.ini file I defined MLROOT=/Applications/MATLAB_R2011b.app The problem is that when clicking the app COMSOL with Matlab a problem appears. checking the setlog I says...
View ArticlePipe Heating Control HELP!!!
Hey everyone, Attached is a model I have of air being heating as it passes throug a pipe. Right now the Q (heat source term) was calculated to raise the temperature of the pipe from the inlet temp of...
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