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-   -   Rise of a spherical bubble terminal velocity (https://www.cfd-online.com/Forums/openfoam-solving/58449-rise-spherical-bubble-terminal-velocity.html)

sega June 4, 2008 14:54

Update on the case. The veloc
 
Update on the case.
The velocity gradient mentioned above was due to boundary influence.

With a slightly bigger geometry the result is within 1.4 % error of the estimated value of the terminal velocity.

http://www.cfd-online.com/OpenFOAM_D...s/mime_pdf.gif risevelocity.pdf

ngj June 6, 2008 04:44

Hi Sebastian I have just fo
 
Hi Sebastian

I have just found a tool called sampleSurface, where you can extract isoSurfaces. Look in the template-dict in

~/OpenFOAM/OpenFOAM-1.4.1/applications/utilities/postProcessing/miscellaneous/sa mpleSurface.

Have a nice weekend,

Niels

azman October 20, 2008 15:32

Hi all, sebastian, thanks
 
Hi all,

sebastian, thanks for sharing your case in this forum. at least I know now what to look out when simulating rising bubbles with InterFOAM. I have been playing around with the InterFOAM solver for about 2 weeks now, and was toying with the idea of solving the concentration field of oxygen bubble rising in water using InterFOAM.

I am not sure whether you or anyone have ever tried it.

The first strategy that came to my mind was ..just adding the scalarTransport equation (just like how it was defined in the ScalarTransportFoam) in my InterFoam solver, after the gamma equation and velocity equation is solved.

solve
(
fvm::ddt(C)
+ fvm::div(U, C)
- fvm::laplacian(DT, C)
);
with DT = gamma*D02_liquid + (1-gamma)*DO2_air

I am however not sure how I can include a jump condition at the interface, such that CO2_liquidinterface = HenrysKoeff*C02_gasinterface. I fear that this is not possible with the VOF method since VOF doesnt track the interface per se, but just the vol. fraction of each cell, and magically reconstruct the interface. Am I right?

I recently came across a paper from Bothe et al., about direct numerical simulation of mass transfer between rising bubbles and the surrounding liquid that can be accessed through the link below.

http://chemie.uni-paderborn.de/fileadmin/chemie/Arbeitskreise/Warnecke/Literatur /bubblyflows.pdf

In their work with a self-built fvm code, the VOF method was used too, with the PLIC method to reconstruct the interface. The scalar transport equation was solved as follows:

Inside each phases:
dC'/dt + div(C'*u) = DT.grad(C')

whereby C' = C_liq at the liquid phase
C' = C_gas/H at the gas phase
DT (as above)

at the interphase:
C'_L = C'_G
D02_liquid*grad(C').n = H*D02_Gas*grad(C').n

Does anyone know what to include in the solver, such that the condition at the interphase is fulfilled.

isabel June 26, 2009 08:19

How do you use fundySetFields?
I want to define a spherical bubble of radio 0.001 and center 0,0 and I have typed:

funkySetFields . . -field gamma -expression 0 -time 0 -keepPatches -condition "pow(pos().x,2) + pow(pos().y,2) < pow(0.001,2)"

But I received this error:

bash: funkySetFields: command not found

ngj June 26, 2009 08:22

Search this forum, and you will find the place, where it can be downloaded as an add-on to OF. Further you will find a thorough wiki on the subject.

Best regards,

Niels

brugiere_olivier July 6, 2009 09:11

Hi all,

I have a bubble and I would like make the same graph than Sebastian. I have find the velocity 's maximun. But now I would like find the cell where this velocity is localise.

Thank's for your help

Olivier

sega July 6, 2009 10:05

Quote:

Originally Posted by brugiere_olivier (Post 221589)
Hi all,

I have a bubble and I would like make the same graph than Sebastian. I have find the velocity 's maximun. But now I would like find the cell where this velocity is localise.

Thank's for your help

Olivier

I have chosen the center of of the bubble for my plots.

brugiere_olivier July 7, 2009 03:25

Thank's to your help, but how do you find the center of the bubble ?
Because I can't fetch your archive barycenter.zip

sega March 3, 2010 17:11

Oh, this has been far in the past.
I was stumbling about your question just today.
Unfortunately I can't fetch the file for myself and I have lost it due to some system error ...

Can anyone post it again?

isabel March 4, 2010 03:42

Hi sega,

There is a paper in which is defined the rise velocity: "Thermocapillary motion of deformable drops and bubbles" by Hermann, Lopez, Brady and Raessi.
In this paper, the equation (3.2) is used to compute the rise velocity of a bubble.

bita.kh January 30, 2011 05:39

rising bubble
 
hi all

i simulate rise of spherical bubble with interfoam,but i can't open cases in this forum,can anyone help me?:)

sega January 30, 2011 06:10

1 Attachment(s)
Quote:

Originally Posted by bita.kh (Post 292806)
hi all

i simulate rise of spherical bubble with interfoam,but i can't open cases in this forum,can anyone help me?:)

If by "Case" you mean "Thread", try to use the "New Thread" button. :)

duongquaphim September 27, 2011 10:01

Hi Sebastian,

I saw in the first post that you used symmetryPlane with interFoam but you found some problems. Did you find ways to fix it? I am also facing problems with using symmetryPlane in interFoam as in my post http://www.cfd-online.com/Forums/openfoam-solving/92524-strange-pressure-behaviour-symmetricplane-boudary-condition-interfoam.html.

I hope to hear your comments on this.

Regards,

Duong

srikanth_b October 26, 2011 14:39

numerical dispersion in OpenFoam
 
hi Sebastian,
I am a student (new to OpenFoam) and am working on studying the rise behavior of bubbles in sheared liquids. I am using a 3D case without axial symmetry and am simulating flow in a linearly sheared rectangular column.
Due to the large size of the column I am unable to use a mesh with a resolution greater than 10 cells per diameter. I am also facing the same problem of smearing in testcases as fine as 15 cell per diameter.Have you found a way of resolving this.

P.S. I am also working in Fluent and the same mesh works perfectly without any smearing.Is this an advantage of PLIC over Interface compression ?
In anticipation of your reply
Regards

kmooney November 1, 2011 13:12

There is a good comparison of the performance of various reconstruction methods here if your interested:
Volume Tracking Methods for Interfacial Flow Calculations, Murray Rudman 1997. International journal for numerical methods in fluids.

I'm guessing the PLIC is saving you from poor interface resolution in the Fluent cases. Unfortunately it's not currently implemented in OpenFOAM although I believe there are some people working on it for structured hex meshes.

Hrushi November 19, 2011 09:26

barycenter and drop rise velocity
 
Quote:

Originally Posted by sega (Post 205371)
Hello.

I received a question about how I calculated the terminal velocity.

I have used a post-processing tool I got from the university. I don't know in detail where it comes from, but it was really useful:

http://www.cfd-online.com/OpenFOAM_D...hment_icon.gif barycenter.zip

The tool calculates the location of the mass center of the phase gamma=0 at each timestep.

I tun the tool over my case and put the results into a file named 'center'.

barycenter . . >center

Then I picked the times and positions of the masscenter and calculate the displacement over time which is representing the rising velocity.

Greetings. S.

Hi Sebastian,

I am able to simulate drop rise velocity using interFoam solver. Then I ran barycenter utility as posted above successfully.
I am now stuck at how to extract the time and barycenter coordinate (say in .xy format)?
So that I can calculate instantaneous drop rise velocity over a time.

How did you pick the times and position of the masscenter from center file generated using barycenter utility?

Hrushikesh

sega January 7, 2012 05:03

Quote:

Originally Posted by Hrushi (Post 332772)
Hi Sebastian,

I am able to simulate drop rise velocity using interFoam solver. Then I ran barycenter utility as posted above successfully.
I am now stuck at how to extract the time and barycenter coordinate (say in .xy format)?
So that I can calculate instantaneous drop rise velocity over a time.

How did you pick the times and position of the masscenter from center file generated using barycenter utility?

Hrushikesh

Well I used
Code:

barycenter > center
to produce an output file "center", deleted everything i didn't want manually and imported the data with MATLAB ...

A.J.Chaves August 21, 2012 11:53

Barycenter utility
 
Hello

I am new here in the forum and I have been working with the same case of the bubble rising. I'm using interDyMFoam and an parallel processing to simulate the case. Now I want to calculate the barycenter of the bubble so I can get the velocity in each step of time. I downloaded the barycenter utility, but when I try to install it, an erro message occurs.

ana@ana:~/OpenFOAM/OpenFOAM-2.1.0/applications/utilities/postProcessing/barycenter$ wmake
Making dependency list for source file barycenter.C
could not open file readEnvironmentalProperties.H for source file barycenter.C
SOURCE=barycenter.C ; g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3 -DNoRepository -ftemplate-depth-100 -I/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/transportModels -I/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/transportModels/incompressible/lnInclude -I/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/transportModels/interfaceProperties/lnInclude -I/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude -IlnInclude -I. -I/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/OpenFOAM/lnInclude -I/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/OSspecific/POSIX/lnInclude -fPIC -c $SOURCE -o Make/linux64GccDPOpt/barycenter.o
barycenter.C:49:44: error: readEnvironmentalProperties.H: Arquivo ou diretório não encontrado
In file included from barycenter.C:52:
createFields.H: In function ‘int main(int, char**)’:
createFields.H:92: error: ‘g’ was not declared in this scope
In file included from barycenter.C:55:
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/setInitialDeltaT.H:35: error: ‘CoNum’ was not declared in this scope
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:3: warning: unused variable ‘nOuterCorr’
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:6: warning: unused variable ‘nCorr’
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:12: warning: unused variable ‘momentumPredictor’
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:15: warning: unused variable ‘transonic’
make: ** [Make/linux64GccDPOpt/barycenter.o] Erro 1
ana@ana:~/OpenFOAM/OpenFOAM-2.1.0/applications/utilities/postProcessing/barycenter$

I'm also a new user of the linux system but I guess the erro occurs because I'm using an new version of the OpenFoam (2.1.0) instead the original one that the utility were made for.
If anyone could help me, I would be grateful.

Hrushi August 22, 2012 02:09

Quote:

Originally Posted by A.J.Chaves (Post 378000)
barycenter.C:49:44: error: readEnvironmentalProperties.H: Arquivo ou diretório não encontrado
In file included from barycenter.C:52:
createFields.H: In function ‘int main(int, char**)’:
createFields.H:92: error: ‘g’ was not declared in this scope
In file included from barycenter.C:55:
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/setInitialDeltaT.H:35: error: ‘CoNum’ was not declared in this scope
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:3: warning: unused variable ‘nOuterCorr’
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:6: warning: unused variable ‘nCorr’
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:12: warning: unused variable ‘momentumPredictor’
/home/ana/OpenFOAM/OpenFOAM-2.1.0/src/finiteVolume/lnInclude/readPISOControls.H:15: warning: unused variable ‘transonic’
make: ** [Make/linux64GccDPOpt/barycenter.o] Erro 1
ana@ana:~/OpenFOAM/OpenFOAM-2.1.0/applications/utilities/postProcessing/barycenter$

I'm also a new user of the linux system but I guess the erro occurs because I'm using an new version of the OpenFoam (2.1.0) instead the original one that the utility were made for.
If anyone could help me, I would be grateful.

Hi Angelo,

Yes, you are right. You need to make some minor changes in that code. I had done it a year back. I will have to look into my old files. If I get it, I will upload it here asap.:)

Hrushi September 21, 2012 15:24

baryCenter
 
1 Attachment(s)
Hi Angelo & Tayo

Here is the updated version of baryCenter baryCenter-of201.zip utility. I have tested it on OpenFoam-201. You can comapre the each file in zip archive with one that you have to recognise the changes one needs to make it usable in OF201.

Hope it helps.

Regards
Hrushi


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