Fluid Structure Interaction with Two Phase Flow

September 13, 2017, 5:39 am

Hello to everybody,

I am working on a simulation trying to reproduce the flow of two fluids( gas and liquid) flowing on a silicone membrane which gets deformed due to the fluid flow.

I saw the tutorial about FSI here linked (www.comsol.it/model/fluid-structure-interaction-361) where is simulated the flow of only one fluid. I have problems to simulate the same physic with two different fluids. I tried to couple FSI and Two phase flow, phase field but it didn't work.

How can I solve this problem?

Thanks in advance

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Complex pressure values

July 7, 2017, 6:44 am

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Hi all,

Simple problem.

I have plotted the acoustic pressure but I would like to get the complex values for this (the real and imaginary part). How can I do this?

Also would it be possible to pick a boundary and receive all the values for that particular boundary?

Cheers in advance!

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out of memory in comsol

September 13, 2017, 9:05 am

≫ Next: How to excite all possible modes in a micro resonator

≪ Previous: Complex pressure values

Hi all
can any one help me with this prolem please . i have problem when the program working after sometimes tells out of memory . however i am working on sever and it has 256GB .

thank you

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How to excite all possible modes in a micro resonator

September 13, 2017, 11:56 am

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HI,

I am using Frequency Domain in WaveOptics Module to find resonant frequencies of a 3D micro resonator. The range of wavelength I search is in between 400nm to 600nm with a step of 1nm. However, the resonant frequencies I obtained from the Intensity Spectrum are not agree with the ones I obtained using EigenFrequency Study.

I noticed that in COMSOL examples, it says 'the excitaion should be as isotropic as possible, so it can excite all possible mode'. What does isotropic mean? If I use Edge Current as Excitation source, where should I excite on the resonator? Is there any guidence that I can follow?

Thanks a lot!

Best regards

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Solution Disappeared

September 13, 2017, 4:10 pm

≫ Next: Geometry settings tab not showing

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Hi

I am trying to solve Free and Porous media fluid flow in COMSOL.

The model is 4.7 millions DOFs and I am using direct MUMPS solver. I have Intel Xeon E5-264016 (2 sockets/ 16 cores) and 192GB of RAM.

The problem I am facing is that the residual tolerance of 0.001 is reached [the nonlinear solver diplays 100% of solution progress].

But the solver did not stop and continue to do calculations [the nonlinear solver diplays new 18% of solution progress] until the computer restarts without my command and the solution file is disappeared

I dont understand why this happening and what to do

Can anyone please help with this ?

Thank you in advance

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Geometry settings tab not showing

September 13, 2017, 9:14 pm

≫ Next: Acoustics and Heat Transfer Interactions

≪ Previous: Solution Disappeared

I am new to COMSOL. While working on my model, I did something that I don't know now and as a result, my geometry settings window is not available anymore. Tell me how to make my COMSOL interface (the window that opens when we open COMSOL working environment for the very first time) becomes same as it was when I installed it. I am attaching the picture of my COMSOL with this email. In this picture, I have drawn a sphere but I can't set its size, center etc. the window that does these things is hidden. Please help me solve this issue.

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Acoustics and Heat Transfer Interactions

September 13, 2017, 11:11 pm

≫ Next: Convert space between lines to Solid or surface

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Hi everyone,

I am very new to COMSOL and have a question about the acoustics package. Does COMSOL take in account the effects of acoustic vibrations on heat transfer through materials? Any information at all is helpful and appreciated.

Thank you

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Convert space between lines to Solid or surface

September 14, 2017, 1:33 am

≫ Next: For generating 1.2/50us impulse voltage wave in Comsol 5.3

≪ Previous: Acoustics and Heat Transfer Interactions

Hello,

I´m new at COMSOL. My first question according to the geometry is the following...

I built a parametriced Body with Lines. Now i want to make the space between the lines to surfaces or make the whole space between the lines to one solid. But with the convert function it doesn´t work. Can anybody help me?

Thankyou!

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For generating 1.2/50us impulse voltage wave in Comsol 5.3

September 14, 2017, 2:30 am

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≪ Previous: Convert space between lines to Solid or surface

The below post is related to an [archived discussion](/forum/thread/14102/is-it-real-to-simulate-full-lightning-impulse-1-2-50-us-in-comsol-4-0)
***
[start here]

Hi,

I have read you comment/suggestion regarding impulse voltage.

Can you please tell procedure in detail to create impulse voltage in Comsol 5.3?

Thanks & Regards,
Abhishek
L&T Technology Services

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//phoneyed3.rssing.com/chan-3365779/article19370-live.html

July 13, 2009, 11:42 am

≫ Next: Polymer thermal stress analysis, error: Out of memory during assembly

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Polymer thermal stress analysis, error: Out of memory during assembly

September 14, 2017, 6:38 am

≫ Next: How to connect electrostatic module to creeping flow

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Dear all,

I have confronted a problem when I wanted to simulate the polymer cooling process with "thermal stress" simulation. The Error showed: Out of memory during assembly.
I noticed that the comsuming RAM was increasing quite fast when the simulation starts, then the RAM memory is not enough. I noticed that when I just simulate the thermal process, everthing was good. Only when coupling with the Solid Mechanics study, the problem happened.
Could anyone give me some suggestions about the reason? I would assume it to be BC setting or multiphysics coupling.
I would attacht the model here as well.
Thanks!

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How to connect electrostatic module to creeping flow

September 6, 2017, 10:29 pm

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As you know we have a volume force term in navier stokes equation which is due to electric field or electric potential gradient (ρe*E ,E = −∇ϕ ) I want to introduce this force in volume force but I don't know how to write gradient term, I mean I cannot find the annotation or syntax to introduce gradient to COMSOL.

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Import SEM image as geometry

September 14, 2017, 10:45 am

≫ Next: Heat transfer thru different process steps

≪ Previous: How to connect electrostatic module to creeping flow

Hello All,

I have SEM image of a geometry that I want to import to the COMSOL.
I have tried importing by Definition>>Functions>>Image, but that just import the image and it can not be used as a geometry.

Does anyone have any idea how to import SEM images to COMSOL?

Thanks,
Hamed

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Heat transfer thru different process steps

September 14, 2017, 11:17 am

≫ Next: Electrostatic (es) to solid mechanics (plain strain) domain coupling issue

≪ Previous: Import SEM image as geometry

Hi!

Im working with a process where a piece om material is taken out of a oven at a ceratin temperature, T. Then it experiences convenction and radiation during 5 sec, i call this step1. Then, in step2, where i put it in a mould which gives me different scenarios, for example, bottom surface has a boundary temperature, Tb and only convection on two sides. How do i connect the result from step1 to step2? As of now i have two different physics, "heat transfer in solids 1" and "heat transfer in solids 2", both with different boundaries etc, see attatched picture! I tried to have study 1 and study 2 and in study 2 get values from study 1 but didnt get it to work.

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Electrostatic (es) to solid mechanics (plain strain) domain coupling issue

September 14, 2017, 12:05 pm

≫ Next: Suggestion to Radiation error: exactly one adjacent domain must be opaque. "

≪ Previous: Heat transfer thru different process steps

Hi,

I am trying to simulate a simple cantilever beam using electrostatics and solid mechanics coupled by moving mesh domain. The space charge densities are assigned to different domains within beam and electrostatic results are verified using theoretical calculations as well as other FEA tools.
I am trying to calculate force generated by electrostatic domain and couple to solid mechanics by Maxwell's stress tensor in both X and Y direction using boundary load. The resultant output displacement is much smaller from theory and other FEA tools. Could you please help me to understand the mistake I am doing here? I have attached my simulation file here for reference.

Thanks in advance

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Suggestion to Radiation error: exactly one adjacent domain must be opaque. "

September 15, 2017, 12:14 am

≫ Next: muti-turn coil

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The below post is related to an [archived discussion](/forum/thread/8909/radiation-boundary-condition-on-comsol4-0)
***
[start here]
I think, for a diffuse surface, you need to (1) point out a Opaque domin under the option of (Heat transfer in solides) or (2) set the radiation direction not to be opacity controlled.

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muti-turn coil

September 15, 2017, 2:55 am

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≪ Previous: Suggestion to Radiation error: exactly one adjacent domain must be opaque. "

(http://)(http://)The below post is related to an [archived discussion](/forum/thread/86941/reference-edge-current-direction-in-a-multi-turn-coil-domain)
***
how to find the automatic current calculation ? I have set the coil type to the numeric and set the next to the circual current,But I cannot find the automatic current calculation under the multi-turn coil.![](http://)

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cell Reynold number

December 28, 2011, 12:54 am

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Dear all,

I have some confusion regarding cell Reynold number option provided in COMSOL post-processing. What I understand is that cell Reynold number is calculated with velocity and length within/from a mesh element. Is it correct? If it is, it will show changes/different value of cell Re when i applied different mesh size, right?
So my question here is, what is the function/usage of cell Reynold number? or in what case it is normally applied?

Thanks a lot!

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Calculating torque or bending moment of a fixed blade in non-uniform flow

September 15, 2017, 11:31 am

≫ Next: ADHESIVE JOINT STRESS BETWEEN GLASS FIBER COMPOSITE SHEET AND ALUMINIUM SHEET

≪ Previous: cell Reynold number

Hi all,

Im doing a low fidelity analysis that simulates a blade rotating in a fluid where the fluid velocity varies linearly along the span of the blade (this is just an early stage model - not meant to be robust).

It's of interest to find the torque about the fixed location at the root due to drag but im having trouble doing this directly. I can easily integrate across the entire surface to find the magnitude of the total drag using spf.T_stressx, but this doesn't help as the line of action is unknown and changes with each design (I'm running a parametric study that alters some shape parameters).

Is there any way to integrate the drag along the span multiplied by the distance from the fixed location? This would give me the torque but I cant figure out how to do it with the derived values tool or by exporting nodal data.

Any suggestions would be appreciated, thanks.

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ADHESIVE JOINT STRESS BETWEEN GLASS FIBER COMPOSITE SHEET AND ALUMINIUM SHEET

September 15, 2017, 9:01 pm

≫ Next: width of a lumped port

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I'm currently working on a project which deals with stress analysis of adhesive joint between a glass fibre-polyester matrix composite and aluminium AA6061 alloy. As I'm new to comsol, can someone guide me regarding how to put adhesive layer between above mentioned sheets and also how to carry the tensile test on the final specimen.
Any leads would be helpful and appreciated.
Thank you.

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