Hi,
I need to model a hexagon spiralled channel in a similar fashion of a circular one, which is taught here: https://www.comsol.com/blogs/how-to-build-a-parameterized-archimedean-spiral-geometry/
Would anyone have any hints? Thanks in advance!
↧
Hexagon spiralled channel
↧
Problem in the creeping flow model: does not work in one case but works in a very similar case
Hi, I'm having a problem with comsol : I do not know if it come from a ill-posed physic or if it's a "numerical problem". Indeed, I use the creeping flow model on a rectangle with an inlet (p = 1) to the right, outlet (p=0) to the left and symmetry up and down. The result is given in the first picture below and it doesn't work. Then I consider the same geometry minus a circle (its center is on the lower border of the rectangle ; see the second attachment below) and with the same boundary condition : here the computation is done by comsol and the result seems consistent (cf. last attachment). I do not understand why it works in one case but not in the other. Do you have any idea where this may come from?
↧
↧
Balanced and Unbalanced Signals
Hello,
I would like to study on baluns by using COMSOL. I need to convert between a balanced signal and an unbalanced signal. I had assumed that the coaxial lumped port is unbalanced. But after I did some simple test on the Dipole Antenna with a Quarter-Wave Coaxial Balun example, I got confused.
The reason of my confusion is that, There is not a real difference between the electric field distribution on the dipole arms when the balun exists and doesn't exist. I attached both images to this discussion.
Without a balun, Is it supposed to be left arm is not electrified since it is connected to outer metallic shield?
↧
Periodic Boundary condition in a multiphysics.
Hello everyone,
I am new to COMSOL, and I was in a confusion about the boundary conditions applied to the multiphysics. I am working on a piezoelectric model and want to apply periodic BC to the model. Do I need to apply it from both physics (solid mechanics and electrostatics) or it is fine if I apply it from just solid mechanics. I also want to know about how to apply initial or external strains on points rather than domain.
Thanks
↧
How to extract the stiffness matrix and mass matrix of the element in comsol
How to extract the stiffness matrix and mass matrix of the element in comsol， I know that the code mphmatrix can extract the global stiffness matrix ，global mass matrix and so on. Yet i want to extract the matrix information of element，but i do not how to extract it? can comsol solve this problem. Or someone can offer me other methods, it is thanksful. If there is no other way, is it only possible to construct a shape function to perform the grouping of the element stiffness matrix.
↧
↧
Heat profile used in different model
Hello, I am pretty new at comsol, I have simulated joule heating physics and achived heat profile across my design. Now I wish to simulate stress induced by heat in the same model. The problem with simulation is that I am unable to work with identity pair in solid mechnics and I am using identity pairs joule heating simulation. I tried changing the from identity pair to contact pairs but they won't work(perhaps I don't know how to make them work). So I have decided to use the heat profile achived in the joule heating simulation for solid mechanics. Is there any way to simple import the heat profile or use that temperature to continue with simualtion?
↧
why partial derivative of the hydrostatic pressure field equals to 0?
Excuse me, I solved the two-dimensional hydrostatic pressure field solid.p. The hydrostatic pressure solid.p distribution is not uniform. Use d(solid.p, x) to solve the partial derivative of solid.p along the x direction. Why is the calculation result 0?
↧
How to download the software--comsol multiphysics?
Hello,can you help me to find the way about downloading it?I can't find corresponding download link.I want to study it in some experiments as a college student.Thank you.
↧
Surface plot of velocity in Comsol for a 2D flow case
If I want to plot surface velocity profile in Comsol such that we have a plane on horizontal surface and variation of velocity is shown in vertical direction as if it appears to be a truncation, how to do that? I am attaching a similar figure of what I need to draw. If anyone has any idea regarding this, kindly help. Thanks.!
↧
↧
Implementation of Preisach Hysteresis Model
Hi, I have implemented the model of a common mode choke for electrical drives, now I have to calculate the magnetic losses of the ferromagnetic core. In order to do this and to make the hysteresis curve BH, I would use the Preisach Model. Someone could give me directions point by point on how to do it. Thanks a lot
↧
Implement function in Type field
Hi,
i have a question about my problem. It is a Iron block with an hole (borehole). On the inside of the borehole i want to heat the block with the "boundary heat source --> heat rate" function. It works for all the surface (uniformly). But now i want to try to heat the surface with the interpolation function (already done with excel for e.g and import in comsol.) or piecewise. The total heat have to be 92W. The field is always yellow. Maybe anyone have an advice or the solution.
Thankfully
Emir Iljazi
↧
How to calculate the rotational speed of pm-motor
Dear all
I am Joey.
I am simulating a permanent magnetic motor with rmm physics. I need the torque, the rotational speed of rotor, should I define a parameters before calculating? Also, if you know more about motor, I am learning about the way of controling the pm-motor, hope you can share your idea with me.
Regards
↧
magnetic field due to thin solenoid
Hi. I'm completely novice in comsol, and I'm trying to simulate magnetic field due to solenoid.
I was wondering how can we simulate "n turn per unit length [m]" in comsol.
Here, I want to have a solenoid of length 50mm and n = 100 turn per m, so I've put 5 for the values of N turn in coil domain, but I'm unsure about the values that I got.
For a single coil, it has approximately 5.52 micro T, and if I extend that into solenoid with 5 turns for total length, it should give around 5.52*5 ~= 25 micro Tesla.
But as you can see from the attached file, it gives around 80 micro T, which seems wrong.
I've attached both single coil and solenoid, with same radius and distance from the point that I'm interested in.
Also, I'm trying to simulate a thin solenoid, which means we can ignore the thickness of the wire. So i've made a geometry of cylinder which has a really small difference between inner and outer radius. Is it valid to do so?
↧
↧
Frequency response analysis of a damped piezoelectric resonator
I've been having a problem doing frequency response analysis for a quartz tuning fork. I was able to obtain a decent frequency response without any damping and it kinda forces the response to be a very sharp resonance with finer steps. I tried to add isometric damping similar to the shear stress quartz oscillator and it creates a nice response except at the resonance where there's a drop in its amplitude. I have no idea what is the cause of this problem. I have added an attachment of the responses with and without piezoelectric damping.
↧
How to evalute stress on gauss point with MATLAB?
The below post is related to an archived discussion
[start here] Difference B/W Von Mises Stress And Von Mises Stress Gauss Point Evaluation.
Does any one know what is the difference between simple von Mises stresses and von Mises stresses Gauss point evaluation. Also what is the difference b/w the effective plastic strain and simply strains in x and y directions.
How to evalute stress on gauss point with MATLAB?
↧
The model - An immersed cantilever beam
I am interested in this model's details (designing and simulation), so if any could help me with any attachmet files for the same.
↧
Simulation of MOSFET model.
I want to simulate Mosfet using 2D plot . Can anyone suggest some tutorial or help me understanding the MOSFET simulation
↧
↧
Changing phase field model in comsol
Hello everybody,
I want to change the phase field equation in the comsol and I don’t know how I can do it.
In the attachment, you can find all information about my problem.
Thank you for your help in advance.
↧
Drawing a triangular hole in a cuboid
How can I draw a triangular hole in a rectangular channel? I am currently creating a 2D workplane and after drawing the required geometry in 2D, I am using the difference option. But the triangular region is not being selected. If this would have worked, I would have then used the extrude option.
If anyone has idea regarding this, kindly help.
↧
CATIA Import
Hi,
I am trying to import a CATIA model into COMSOL 51, however I keep getting this error:
Error : Translation aborted due to out of memory allocation problem
However, my model imports fine on COMSOL 54. I am not sure why it is not importing on COMSOL 51? I have tried with various different machines and they all open with COMSOL 54 but not with COMSOL 51. The size is approx 195 mb.
Your help will be greatly appreciated!
Cheers
↧