interFoam - validation for bubble/droplet flows in microfluidics
 

Dear all,

It is a bit ashamed but I would like to share one of our work on the validations of interFoam, titled "Benchmark numerical simulations of segmented two-phase flows in microchannels using the Volume of Fluid method". In this work, we presented three benchmark cases - the steady motion of bubbles in a straight two-dimensional channel, the formation of bubbles in two- and three-dimensional T-junctions, and the breakup of droplets in three-dimensional T-junctions - and provided guidelines to set appropriate numerical settings for a simulation of microbubble/microdroplet flows.

Please find here the link to the paper: http://dx.doi.org/10.1016/j.compfluid.2013.06.024

If you can not download the paper, I am more than happy to send you a copy of it.

With best regards,

Duong

No need to be ashamed. Thanks for sharing!
-Kent

Hi Dear Duong
Thanks for your good paper.
I am new in interFoam. I have two simple questions.
1) how can we apply the smoother function (Eq.9 in your paper) in our problem? I think it can be set: system/fvSolution dictionary, PISO loop subsection was set with m corrections (nCorrectors)
is it true?
2) where should be determined the value of adjustable coefficient "Cγ in Eq.7"?
Thanks
Ali

Could you please share the case setup for openfoam? Best regards

Dear all,

I just got a bit of free time lately to reorganize my data. Here you can find the code and the test cases I have run for my validation. Please be aware that all these validations have been performed with OF-1.6-ext.

Best regards,

Duong

Hi,

I'm not sure but I think that the function fvc::average already exists and do the same operation as your "smooth function".

In the OpenFOAM C++ doc, you can read:

volField = fvc::average(SurfaceField)
Area-weighted average a surfaceField creating a volField.

So you can do your smoothing by :

Regards,

Pierre

Indeed you can also use that function. And it is much simpler I agree.

At the time I implemented that, I would like to have controls on the level of smoothing (averaging) and also to be able to implement different smoothers (which I did not find superior to that simple Laplacian). So that's why you have such a piece of code.

Best,

Duong

Hi Duong,

I just downloded your file (bubble_generation). I am able to blockMesh.

Check topology

Basic statistics
Number of internal faces : 44
Number of boundary faces : 56
Number of defined boundary faces : 56
Number of undefined boundary faces : 0
Checking patch -> block consistency

Creating block offsets
Creating merge list


Further when I run "interFoam" solver I get this error.

paramesh@HP-WS3:~/OpenFOAM/paramesh-2.4.0/run/tutorials/incompressible/pimpleFoam/bubble_generation$ interFoam
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.4.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.4.0-f0842aea0e77
Exec : interFoam
Date : Sep 30 2015
Time : 12:12:41
Host : "HP-WS3"
PID : 10778
Case : /home/paramesh/OpenFOAM/paramesh-2.4.0/run/tutorials/incompressible/pimpleFoam/bubble_generation
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0



--> FOAM FATAL IO ERROR:
keyword PIMPLE is undefined in dictionary "/home/paramesh/OpenFOAM/paramesh-2.4.0/run/tutorials/incompressible/pimpleFoam/bubble_generation/system/fvSolution"

file: /home/paramesh/OpenFOAM/paramesh-2.4.0/run/tutorials/incompressible/pimpleFoam/bubble_generation/system/fvSolution from line 55 to line 132.

From function dictionary::subDict(const word& keyword) const
in file db/dictionary/dictionary.C at line 648.

FOAM exiting


What is the problem?



-Sripad

That's the problem. As Duong stated the case setup is for OF-1.6. You'll need to update the dictionaries for 2.4.0. Compare the case with the tutorial cases and you will fix the error quickly.

Akidess. I notice the next error


PIMPLE: Operating solver in PISO mode

Reading field p_rgh



--> FOAM FATAL IO ERROR:
cannot find file

file: /home/paramesh/OpenFOAM/paramesh-3.0.0/run/tutorials/multiphase/interFoam/bubble_generation_trial/0/p_rgh at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting

You are missing the file p_rgh. Please have a look at the interFoam tutorials.

hey.. do you still have these files?
I wanted to download them and i am unable to get the files from this link

Problem solved, able to download now.

Could you please share the copy of your paper? Best regards

Hi,

I tried to update your solver to run on OpenFOAM 4.1. Unfortunately, I have obtained so much errors... Did you adapt your code to this version of OpenFOAM ? How can I achieve that ?

Best Regards,

Peter.

Hi,

I think that it should be quite straightforward to adapt/implement the Laplacian solver in interFOAM version. However, I did not work on this topic for a while, so I do not know any details to tell you. The only thing I could think about is the difference in library name and the change of alpha field.

Duong

Thank you for the reply. I will try to update the solver, if someone is interested by this update, please contact me, I will share.

Best regards,

Peter

Have a look at the following.


OF-4.x implementation of 'vofsmooth':
I have implemented Duong's "vofsmooth" in OF-4.x.
It was implemented using OF's run-time selection mechanism and a dynamic library trick, such that it should work with any solver (that uses OF's libinterfaceProperties.so: inter(DyM)Foam, compressibleInter(DyM)Foam, multiphaseInter(DyM)Foam, interPhaseChange(DyM)Foam and very likely some more.)
[Disclaimer: I have only tried inter(DyM)Foam in my work.]

See the README.md on GitHub:
https://github.com/floquation/OF-kva...faceProperties

Thanks a lot for sharing your code :-)

Best regards,

Peter

It's weird, but when I compile your code it works. Bun when I'm running the damBreak case, it returns the following error :

Selecting incompressible transport model Newtonian
Selecting incompressible transport model Newtonian
Selecting curvatureModel vofsmooth
kva: curvatureModel::read(vofsmooth);
kva: curvatureModels::vofsmooth::read();
kva: curvatureModel::read(vofsmooth);
#0 Foam::error::printStack(Foam::Ostream&) at ??:?
#1 Foam::sigSegv::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
Erreur de segmentation (core dumped)

Any idea ??

That had certainly puzzled me for some time as well, because the code is correct... However, since I am a self-educated fool (which I bet most of us are) whose messing with dynamic libraries, I was only thinking in terms of code. But although there is nothing wrong with the code, I did mess up the binary-compatibility, as I didn't know that any such thing (ABI) existed.

I am working on a proper "fix", which I should have soon. (That is, I should regain the binary-compatibility.) For the time being, you can easily work around this, as I described right here:
https://github.com/floquation/OF-kva...rties/issues/2
That solution boils down to recompiling your solver; or rather compiling a clone of your solver that is linked against my library.