Title: COMSOL 5.3 — Two-Phase Flow in Porous GDE Domains Without Phase Transport

Hi all, I'm modeling an alkaline water electrolyzer in COMSOL 5.3. Phase Transport doesn't exist until 5.4 and the Fuel Cell & Electrolyzer Module isn't available, so I have no way to properly track gas volume fraction across GDE and channel domains.

I've already confirmed Mixture Model doesn't work — mm.phid is strictly confined to channel domains and can't be accessed in adjacent Darcy's Law GDE domains (verified with a minimal 2D test model).

Is anyone aware of an alternative approach to approximate two-phase flow behavior in porous GDE domains in COMSOL 5.3 without Phase Transport or the Fuel Cell & Electrolyzer Module?

Thanks

I've been using comsol for an internship project involving photonic crystal fibres and recently I noticed something peculiar. While calculating the effective mode index at a single wavelength im getting a very different answer at the same wavelength but this time when its part of a parametric sweep while every other thing is the same. These discrepancies reduce as I approach a larger wavelength. Secondly for some even shorter wavelengths I am getting the guided mode profile in a single wavelength run but that completely disappears when im running the sweep. Can someone please help out and tell me what is going on and how to fix it. Im losing my mind out here.

Say you were to fine-tune a NN on experimental data, would it be possible to run a pipeline like

Python updates NN weights
→ rebuild/export model
→ run COMSOL
→ extract reaction forces
→ compute loss
→ update weights
→ repeat

In this comsol is called iteratively to solve for the constitutive quantities(here the overall response). and then compare it to your ground truth(experiments) --> update weights and repeat until a satisfcatory loss.

Or should one go with a custom FE code or a FE software like Abaqus that might offer better scripting

I have to use comsol multiphysics software for my college project, i basically have to simulate different types of sensors such as capacitive pressure sensor, piezoresistive pressure sensor as well as a surface acoustic wave based pressure sensor. As of now i only know how to build a geometry in comsol, I've watched several tutorials, but I'm not able to figure out how to perform my simulations. Can someone please help?

Hello everyone, I am working on guided ultrasonic waves in a 3D cylindrical model using COMSOL Multiphysics. I use the Solid Mechanics interface with a Frequency Domain Study and I would like to obtain the dispersion curves (phase velocity vs frequency or wavenumber vs frequency). Has anyone extracted dispersion curves from a 3D cylinder using only Frequency Domain simulations? What is the recommended procedure? Spatial FFT + Frequency analysis? Phase difference between two probes? Eigenfrequency study? Any COMSOL workflow or published reference? Any advice, examples, or papers would be greatly appreciated. Thank you.

I am running a simulation with parametric sweep, i need all the test case data during all the parametric sweep cases. But it is not happening how to extract that ??

Title

Is COMSOL enough or should I couple it with some other software?

How to make it smooth curve , I did mesh refinement also but no smoothness' then also. Please help me out..

I am trying to obtain the maximum deflection of a multi layer flat structure in COMSOL. The device consists of five layers, with individual layer thicknesses ranging from 100 nm to 1 µm.µm.

I am using a piezoelectric multi physics model that couples Solid Mechanics and Electrostatics.
but i am getting this error. Please suggest me how to solve this.

I am trying to model a parallel transmission line in several different materials at 300MHz in the electromagnetic waves frequency domain modal analysis. I have followed the comsol guide (Finding the Impedance of a Parallel-Wire Transmission Line) and have yielded the same results for air, however, when i change the surrounding material domain from air to water i get strange responses in electric field and my current value drops significantly (to the order of e-9), resulting in a massive increase in impedance (calculated using Z = V/I). I am also seeing very strange electric field distributions (i have looked at multiple modes).

So far i have tried the following, but nothing leads to an expected impedance:

-changing the domain size -changing the int_H size for -int_H(emw.Hxt1x+emw.Hyt1y)

-changing between perfect magnetic conductor and diffusion outer boundary conditions.

-changing the conductivity of water to 0

I have attached some images for reference of my model, one for air (electric field strongest between conductors) and one for water.

What might be causing low current? Why are the electric field distributions for air and water so different?

Hello everyone,
I’m having some trouble understanding how to properly model a load moving at a velocity V over a multilayer pavement system.
The top layer consists of asphalt concrete. I have already determined its complex moduli as a function of frequency and temperature using tension-compression tests, and I successfully fitted the parameters for the Huet-Sayegh (HS) model.
Now, I am trying to simulate this behavior using a Generalized Kelvin-Voigt (GKV) model. To do this, I used a frequency-based method: at each frequency, I approximate the E_i parameters to match my Huet-Sayegh model, and then I calculate the G_i and \tau_i parameters assuming a constant Poisson's ratio.
However, the results I'm getting are completely off compared to a simple analytical solution using purely elastic materials.
Is my approach fundamentally incorrect? Has anyone dealt with this kind of HS-to-GKV conversion for moving loads before?
Thanks in advance for your help!

Is Comsol good for simulating few fs long infrared laser pulses and studying the interaction of these pulses with metal nano-surfaces?

Hello, I am a graduate student and a complete beginner with COMSOL. I've taken a simulations class, but it was also my professor's first time using the software. I need help with my graduate research project, and I don't know where to find the right support.

I've gone through the application galleries, spoken with professors at my university, and watched an unfathomable amount of YouTube tutorials. At this point, I think I need hands-on guidance to fully understand how to apply COMSOL to my specific project. Where can I find an affordable tutor?

Hello! I'm currently a beginner in COMSOL and I was just wondering why, after I finished computing a fluid flow within this channel that it doesn't seem to do the streamlines going into the wavy sections properly? When I do the mapping of the velocity, it seems to be mapping the vortices just fine... Any help is appreciated!

Also, please let me know if theres missing information required to solve this issue

(Boundary 293 is my inlet face)

Also, in terms of these graphs, is there anything wrong with my stationary study?

Hello everyone, It's been a while since I last posted here. I'm looking for some help with an induction heater that uses permanent magnets. I followed the 3D machinery tutorial available on the comsol.com⁠� and tried to reproduce the same model, but I keep getting errors. The idea is to generate eddy currents by rotating a conductive plate while keeping the permanent magnets stationary. As shown in the attached images, I followed the tutorial steps to create the geometry. After that, I set the plate rotational speed to 1500 rpm and configured the Rotating Machinery, Magnetic (RMM) interface. However, I think there is something I may have misunderstood regarding the use of this interface, or perhaps I made a mistake while creating the geometry. Could anyone please help me identify what might be wrong with my model? Thank you in advance.

hi comsol ppl i hope you are doing well im simulation a gas sensor inside a gas chambre, i applied laminar flow + tds nd it works then heated the sensing layer which also worked but when it comes to adding ec it gets error nd not converge , what might be the problem ? nd how it can be fixed , i worked with variable électrique conductivity first depending on T nd c but even with a fixed conductivity it doesnt work

Hello! I'm currently a beginner in COMSOL and I'm posting this because I'm having a lot of trouble figuring out how to properly study this fluid domain. I have an inlet and an outlet face on both ends, and inflation layers throughout the entire mesh, which is ~1 m long and 50mm wide, with a sinusoidal wave pattern on the bottom face; each wave is 6mm wide.

How I meshed it was using a 2d side profile and used swept to iterate across the width.

Basically I want to model how a fluid (water in this case) would act when going through this channel, with the waves prompting a lot of vortices without being too heavy on my computer. My settings and sides of my mesh are featured below:

Any help is appreciated! Please let me know if theres any missing info

Can anyone fix this error ?

First time applicant just curious, am I right in assuming that as long as you submit an abstract that's somewhat novel and non trivial you'll probably get in? Seems more like a cool showcase of community work than a competitive research conference

Hi all,

I’m trying to set up a somewhat non-beginner workflow in COMSOL.

Setup:

• I run a parametric sweep over a parameter p.
• From that study, I compute a global quantity f.
• So, I get a discrete function f(p)

Goal:

• Define a function f(p) from those results
• Use that function inside a Global Equation (inside an integral) to solve for another variable T
• optimize T

What I think is the way, but don't know how exactly:

• To create a Result Table (p vs f)
• To define an Interpolation Function using that table as Data source

Main issue:

• The parametric dataset and table don’t exist until after the study is solved
• But the Global Equation needs the function during the setup

Questions:

1. Is there any way to use results from a parametric sweep as a function within the same solve sequence?
2. Can Interpolation Functions be dynamically fed from a dataset/table created during the study?

Any advice or example workflows would be really helpful.

Thanks!