Convergence problem with Comsol 4.3b
Hi Everyone When I run the model in the 4.3a, it can work very well. The convergence firstly is about 1e4 to 1e5. When the comsol software is updated from 4.3a to 4.3b, the convergence becomes 8e8 and...
View ArticleFor a 3D geometry, is there anyway to get data from one of the plane without...
I have a 3D cylinder, is there anyway for me to get the information on the top surface and feed the information back to my simulation? is the boundary probe the only way? Or is there any way I can say...
View ArticleLift and drag force
Hi all, I am simulating a 2D, turbulent flow over the airfoil. In the post-processing level, I do not know how to get lift and drag forces applying on the airfoil. To compute reaction forces, As far as...
View ArticleInitial Values of a Simulation
Hello, I'm trying to use in a time dependent simulation as initial values part of the values I have solved in a previous simulation. I want to use part of the solution, and give other values different...
View ArticleHow to unite objects with assembly mode?
Hi everyone, I'm modelling coils using the Multi-Turn Coil Domain, and I'm having trouble getting the magnetic fields to work when I finalize the geometry with an assembly (I need to use assembly mode...
View Articlehow to show the error curve
Hi All, Normally there is an error curve to show the convegence speed when running a case. However, I closed some windon in Graphic and this error curve is not shown. Wihout this curve, I am not able...
View ArticleTime integration of a variable over the domain
Hi, I am solving a periodic fluid flow problem over a 2D domain. I need to find the time averaging of the term u*ux+u*vy at each point on the domain. I tried defining a global ODE but it gave an error...
View Articlesegregated vs fully coupled solver in comsol
Hi All, I have compared these two solvers for a heat transfer case with surface-to-surface radiation. Acutually simulation results, i.e., temperature distribution in the domain, are quite different....
View Article3D Wall Shear Stress
I realise this may have been asked before, but I'm running a CFD simulation of blood flow through a 3D cerebral aneurysm model. Initially, I have a laminar flow study in which I would like to visualise...
View ArticleStep function
Very simple question, but I can't find out how to do it. I have a external temperature, "Temperature 1", which is 100 C. After 330 seconds I would like it to drop 80 degrees to 20 degrees. I should be...
View ArticleMEMS
How can i compute the displacement due to gravity in a silicon proof mass in accelerometer and therefore i need to compute the change in capacitance in the accelerometer. My basic question is how do i...
View ArticlePartial integration in full integration
Hello all, I am trying to calculate the induced voltage in a coil in the time domain, the formula is: V=int(part(A)/part(t)dl) i hope you get the idea, that is a line integral for one filament of a...
View ArticleQuick question regarding integration order in Generator 2D model
Hello all, I have a quick question regarding the integration order of the z component of the electric field in the example model "Generator 2D". In the example model the order of integration, and thus...
View ArticleMaking the Generator 2D model into a Motor 2D model
Hello all, How would one change the example model, "Generator 2D" into a motor? Is there a way to make the rps parameter of the "Prescribed Rotational Velocity" property be based on the magnetic field...
View ArticlePDE
I am currently working on COMSOL 4.0a. Can anybody tell me how the variables for stress are defined in COMSOL? Since I want to define a Coefficient PDE, which its diffusion coefficient (c) is coupled...
View ArticleTime dependent study on a 3D multiturn coil inside of an electrical circuit
Hello, I am trying to model the voltage in function of time across a 3D multiturn coil inside of an electrical circuit. To do this I use the Magnetic Fields and the Electrical Circuit physics and a...
View ArticleDefine an arbitrary EM wave
Hello I am new in Comsol and i have a problem : i want to calculate SAR for SAM phantom for different types of EM waves. but the source of EM waves ( signal generator ) isn't important. is there any...
View Article3D RF Module Calculation on Multiple Cores
I am planning to build a computer for running Comsol, and was hoping to find out how well Comsol can utilize multiple cores for RF Module calculations. The most demanding calculation that we would like...
View ArticleCapacitive Shielding
Hi everyone, I'm trying to model a capacitive shield made of aluminium. The shield function is to interrupt the capacitive coupling between un helical coil and a charge inside the coil. Our objective...
View ArticleAcoustic-Structure Interaction
Hi, I'm trying to solve a time-dependent Acoustic-Structure problem that consist in a acoustic pressure applied in the inlet of a tube as a boundary condition, in the outlet of this tube I applied a...
View Article