Quantcast
Channel: Latest Discussions - COMSOL Forums
Viewing all 6573 articles
Browse latest View live
↧

Java runtime error occured when I computing model and COMSOL was shut down.

February 2, 2020, 8:30 pm
$
0
0

I am using COMSOL Multiphysics 4.3b.

There was no problem when I compute model with respect to 'heat transfer solid' only.

But when I compute model with respect to 'heat transfer solid' and 'solid mechanics' , after I click the compute button, COMSOL suddenly shut down. And log file is created.

I think there is no problem in model because I can compute it at another computer(It's specifications are lower than mine in every aspect!!!).

Is AMD ryzen not compatible with COMSOL Multiphysics? If it isn't the reason of failure, what is the cause of this problem??

There is log below.

#**

A fatal error has been detected by the Java Runtime Environment:

#

EXCEPTION_INT_DIVIDE_BY_ZERO (0xc0000094) at pc=0x00007ffa48d99f82, pid=11324, tid=11596

#

JRE version: 6.0_20-b02 Java VM: Java HotSpot(TM) 64-Bit Server VM (16.3-b01 mixed mode windows-amd64 ) Problematic frame: C 0x00007ffa48d99f82

#

If you would like to submit a bug report, please visit: http://java.sun.com/webapps/bugreport/crash.jsp The crash happened outside the Java Virtual Machine in native code. See problematic frame for where to report the bug.

#**

I tried again with COMSOL Multiphysics 5.0, it was also shut down and another log file is created. The log is below.

#

A fatal error has been detected by the Java Runtime Environment:

#

EXCEPTION_ILLEGAL_INSTRUCTION (0xc000001d) at pc=0x00007ffa41ac9fa2, pid=14224, tid=9884

#

JRE version: Java(TM) SE Runtime Environment (7.0_67-b01) (build 1.7.0_67-b01) Java VM: Java HotSpot(TM) 64-Bit Server VM (24.65-b04 mixed mode windows-amd64 compressed oops) Problematic frame: C 0x00007ffa41ac9fa2

#

Failed to write core dump. Minidumps are not enabled by default on client versions of Windows

#

If you would like to submit a bug report, please visit: http://bugreport.sun.com/bugreport/crash.jsp The crash happened outside the Java Virtual Machine in native code. See problematic frame for where to report the bug.

Again, there is no problem in model and formula.

* My computer comprises ryzen 5 3600(RAM), Samsung DDR4 16GB(RAM), ASUS a320m gaming(M/B) and GTX 1660 super.

Please let me know how to fix it.
↧
Search

How to deal with geometry overlapping

February 3, 2020, 2:25 am
$
0
0

Hello, I have a geometry model which is continuously transposed cable, so all the strands are tranposed connected, first I draw rectangular and a polygon to define its spine, then I use sweep to model the cable, the thing is, when I finish doing this, I found there are somewhere two strands overlapped each other and I could not have the correct contact pair for later use, I've tried many options in comsol but end up nothing, anyone knows how to deal with it?

↧
↧

Boundary conditions for porous media in dam break case !

February 3, 2020, 7:18 am
$
0
0

I have a dam break simulation created on comsol as seen in the following video https://youtu.be/02tGVX0PRGo

This dam break is simulated using (Two phase flow - laminar - phase field) Now I want to place a porous media in a place as shown in the attached pic

I think that using the model (Two phase darcy law) is the suitable model but not sure.

I am asking what is the boundary condition that i need to specify for this case(porous media) and how to couple the (dam break) with the (porous media)

Thank you in advance

↧

Simple thermistor example

February 3, 2020, 7:46 am
$
0
0

Hello,

I am trying to test an example of using a bisection method in matlab with COMSOL. I've attached a paper that I'm following.

I need to 1) get a simple thermisor Comsol programme 2) run the bisection method in matlab using Livelink with Matlab

Any ideas of where I could start would be greatly appreciated.

Kindest regards, Sinéad

↧

Post processing visualization takes a lot of time than the study solution time. Need tips..

February 4, 2020, 12:46 am
$
0
0
  • I did a 2D Axisymmetric pressure acoustics frequency domain analysis.
  • The solution had completed less than a minute.
  • I wanted to visualize the sound pressure leve on a cut plane from the 3D dataset (made by revolved 2D).
  • But every time I press plot, it takes about 4 to 5 minutes to plot. If i want to change for example the deformation scale and plot again, it take another 4 to 5 minutes.

Is there anyway to solve the revolved 3D dataset so that I can reduce the time for plotting?

I have attached the link to the picture of the result and post processing part. Let me know if mph file in necessary.

https://imgur.com/w9nAsRd

↧
↧

Magneto-elastic modes in magnetic nano-structures after pulse laser excitation.

February 4, 2020, 2:01 am
$
0
0

Dear all Group members, I have moved to comsol for one of my problems which require multiphyics but I have no idea where to start as I am a novice to this Software. Probem description is below: I wanted to simulate magnon and phonon modes excited by a femtosecond laser in a magnetic material nanostructures (working as a magnonic crystal as well as phononic crystal at a same time). Due to the excitation, some of the magnon and elastic modes get coupled and leading to locked spin wave modes.
Please let me know how can I proceed to simulate such modes and if there is some relevant literature, help me with that too. Thank you in anticipation.

↧

Surface reaction

February 4, 2020, 2:26 am
$
0
0

Hello, I'm simulating this case: a channel in which an exothermic reaction takes place on the surfaces. I'm using " surface reaction " and trasport of diluted species for the mass transfer. I'm new in comsol. In the phisycs " Transport of ...." i have to use some condition on the boundary or automatically there is a diffusive flux?

↧

Comsol crashes only when computing "solid mechanics"

February 4, 2020, 3:49 am
$
0
0

I have a problem using COMSOL Multiphysics.

When I computing a "heat transfer in solid " model, there is no problem.

However, if I computing a "solid mechanics" model, the COMSOL crashes and "hs_err" file comes up.

My computer RAM is sufficient to compute the models(16GB). And computing the models in another computer makes no trouble.

Although I reduce the number of meshes, COMSOL still crashes, even faster.

In addition, what I found is that CPU does not worked after I clicked the "compute" button.

Right after I clicked, the usage of CPU rised up to 33% and didn't rise any more. And then CPU usage decreased and, at that time, COMSOL was shut down.

My CPU is AMD Ryzen 5 3600 My GPU is Geforce 1660 super MY RAM is 16GB

Please tell me how to fix it.

↧
Search

Finding the mode shapes at the outlet

February 4, 2020, 5:17 am
$
0
0

Hello,

I am currently modelling a rectangular duct with the acoustics module. I am feeding various modeshapes e.g (1,0) (1,1) etc in the inlet via the port functionality and would ideally like to find what modeshapes come out downstream in the duct.

I have attempted modal analysis studies finding multiple modes in the outlet, yet this only gives the effective index value. I wonder is there a way of converting this into the modeshapes present e.g (1,0) or (2,0)? Is this even a function possible in COMSOL?

I saw this post using dispersion curves: https://uk.comsol.com/blogs/how-to-use-dispersion-curves-to-analyze-fluid-filled-pipes/?fbclid=IwAR1SrEapN4MJmnAOqUEr90PkxJ8CBdEEck__e0Sqoy4Dpe7589EI10zFt_4#goto-comments But I am unsure how to apply what is mentioned in my own models.

I wonder if anyone has had to do a similar analysis and has any pointers for me?

I would be really grateful for any help.

Thanks

Liam

↧
↧

Overhead Power Lines

February 4, 2020, 12:17 pm
$
0
0

Hello everyone,

I have the next problem that I do not know how to solve, I have a cable made of steel and aluminum wires and I would like to observe the heat distribution of this cable if it is traveled by a current of 800 A, but the aluminum I would like to be a non-linear material in which I can add, through points, a magnetization curve (B-H).

Is this possible? If it is possible, please describe this process.

I have attached a file in which I worked, but the material used is linear.

Thank you in advence!

↧

How to do a parameter sweep of a 2D axisymmetric resonator with EWFD and guarantee I store the effective index of the fundamental 00 mode??

February 4, 2020, 5:35 pm
$
0
0

Hello,

I have a 2d axisymmetric model that is just a rectangular ring resonator waveguide.

I would like to do a paremeter sweep over waveguide geometry and get the effective index of the TE00 or TM00 modes.

The problem is that if I choose to search for my effective index via the "closest in absolute value" or "highest real value" approach as I do my parameter sweet over waveguide geometry, the effective index of the, for instance, TE01 mode becomes the one that the parameter sweet stores and the effective index of the TE00 mode as I would like.

Is there a way to guarantee during a sweep that the effective index of the fundamental mode is stored?

Thank you.

↧

Cluster computing on two desktop computers running Windows 10

February 4, 2020, 11:33 pm
$
0
0

Hi, I have been runing some large-model simulations and would like to utilise serval computers I have in my office, however we don't have a cluster server. I have Comsol installed on every computer. I would like to know if it is possible to configure them to run as a "cluster", because I seem not to find any appropriate article online. So, one computer would act as a headnode and all the others would be nodes, All computers are running Windows10.

Vladimir

↧

Chemical reaction

February 5, 2020, 4:50 am
$
0
0

Hello

How to model a reaction where solid converts into another solid and liquid using reaction engineering physics? Reaction engineering thermodynamic system wizard contains only liquid and gas but no solid.Could anyone suggest how to identify the elements using thermodynamic wizard?

Thanks Alok

↧
↧

Convert a PDE to the Weak Form

February 5, 2020, 8:07 am
$
0
0

Hi,

I have a 2D geometry and time-dependent study with 1D heat transfer in solids, 2D chemical reaction and 2D gas diffusion physics, where I'm using the coefficient form PDEs to model the chemical reaction and gas diffusion.

Now I want to rebuild the model but with using the weak form physics for the gas diffusion. My question is how can convert the following equation into the weak form?

dP/dt+∇. (-D ∇P)=f

where :

P is the dependent variable to solve for.

t is time

∇ is [d/dx, d/dy]

f is a function of the gradient of another dependent variable with time (let's call the other variable CA)

I tried the following two formats but the study didn't converge all the way due to either initial values problems or other errors that I didn't get when solving with Coefficient form PDE, which suggests the weak form expression is wrong.

1st trial:

(-d(P, TIME)-d(-D*d(P, x), x)-d(-D*d(P, y), y)+-d(CA, TIME))*test(P)

2nd trial:

-d(P, TIME)*test(P)+D*(Px*test(Px)+Py*test(Py))+ -d(CA, TIME)*test(P)

I know this is rather a "mathematical" question than a technical one, but would appreciate your help. Thanks!

Eman

↧

Version Control System & Application Builder

February 5, 2020, 1:56 pm
$
0
0

Is there a way to integrate the COMSOL application builder with a version control system to make larger code projects easier maintainable (e.g. GIT or others)?

If there is no such integeration, what is the COMSOL recommended way of handling code versioning in larger code projects?

↧
Search

Piecewise Function is giving Unknown variable error.

February 5, 2020, 8:11 pm
$
0
0

I am using comsol 5.4. When I define a piecewise function and use it to write expression it is giving an "unknown variable error". (see images). What is going wrong here??(units are all correct)

↧

There is a practical question about the solid-liquid interface and I don't know how to model it

February 5, 2020, 8:27 pm
$
0
0

Inject a fixed amount of water into an irregular identified container, and want to determine the distribution of water in the container and the position of the liquid surface under the effect of gravity.     I would like to ask you what module you should choose to model and how to set it up?

↧
↧

Object disappearing due to high aspect ratio

February 5, 2020, 9:42 pm
$
0
0

Hello everybody, I have been using joule heat module to simulate the quench propagation in 60 cm long superconducting thin film. The thin film with the structure of Au/YBCO/sapphire is made of a 100 nm thick gold layer, a 300 nm thick superconducting layer and 0.5 cm thick substrate. But the problem is that the gold layer object automatically disappear in materials interface and joule heat module interface if I define length of thin film beyond 40 cm long.

Any solution is appreciated. Thank you.

↧

Temperature profile around a plasmonic substrate

February 5, 2020, 9:53 pm
$
0
0

I am trying to simulate the temperature profile around a plasmonic gold plate in 2D surrounded by water. I am using 2 modules ewfd and ht in solids and fluids. The input field is getting totally internally reflected at the glass-water interface. The water surrounding the gold plate is open to the air and is initially at the same temperature as the surrounding. I am running a stationary study. I expect the temperature of the gold to be significantly larger than the surrounding water as the thermal conductivity of the gold is much larger than the water. But the temperature difference between the gold and the water is approx 0.02 K. Please let me know about the possible mistake in the implementation of the module and how to move forward from here.

Also when I run a time dependent study, the temperature keeps on increasing and never equilibrates.

↧

Wall Problem in 2Phase Euler-Euler Simulation

February 5, 2020, 11:21 pm
$
0
0

Hello,

I have a problem with a turbulent 2Phase-flow (bubbles in liquid) Euler-Euler simulation for a vessel which contains rectangular internals. I specified the interface between fluid and internals as wall. I get the following error messages for the walls of the internal (translated from the German Version): the Jacobi-Matrix could not be evaluated - Expression: -comp1.ep4+comp1.ee2.ep_w

Does anybody know what I can do to avoid the problem ?

↧
Viewing all 6573 articles
Browse latest View live
Search
<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>