Tuesday, February 9, 2010

VOF Modeling / Applications : Sprays / Droplet Breakup-Deformation-Coalescence .....

One the important problems where more academic fellows look to employ multiphase-VOF approach concerns the breakup of droplets (bunch of stuff can be investigated here : effect of shear, liquid/gas density ratios, velocity of impact etc). They keep publishing stuff back and forth so that they can honor their "commitment to publications!" either during tenure period or post-tenure (this time, the grad students are made to kill the problem !)

Anyways, being beaten down time to time or not, droplet simulations is something I have personally grown fond of ..especially the use of VOF in creating almost real droplets is simply artistic nonetheless !From studies on droplets, emerge, more sophisticated studies such as spray breakup, spray impingement problems etc that are of vast interest in real-world applications.

Having said that, it still becomes essential to find lot of literature in this special field so as to improve one's understanding of the phenomena and the applied numerical methods.

In this edition of the blog, I am going to share some of the droplet dynamics (breakup coalescence) studies that I have bookmarked and read over the years. Hopefully, someone may find it useful to read further into these nicely written work.

I came across this nice presentation sometime ago,

http://cfdcre5.org/cfdcre5-Dietsche.pdf

detailing aspects of droplet breakup from an industrial point of view. The presentation infact shows how droplet entering into a matrix of obstacles gets torn apart ! Mechanisms such as "stick and pull", spreading, etc are nicely indicated. Effect of viscosity ratios on the breakup rates are also available.

Dr. Renardy's work in VOF flows is well known. Their group site has a complete list of VOF papers including their PROST model.

http://www.math.vt.edu/people/renardyy/Research/Publications/

All kind of publications dealing with droplet oscillations, shear flow (droplet dynamics), deformation due to strain in both 2D/3D approximation are available for download.

Also, you can find the PROST model here

http://www.ann.jussieu.fr/~frey/papers/stokes/Renardy%20Y.,%20Prost-%20a%20parabolic%20reconstruction%20of%20surface%20tension%20for%20the%20volume-of-fluid%20method.pdf

How could I not include the famous openFoam based VOF studies: (fundamental presentation by Dr. Jasak)

http://powerlab.fsb.hr/ped/kturbo/openfoam/slides/UniDarmstadt_12Jan2005.pdf

Droplet sedimentation simulation using Finite Element - Level Set Methods - interesting one !

http://www.igpm.rwth-aachen.de/Download/reports/reusken/ARpaper55.pdf

Simulation of the dynamics of insoluble surfactant from Univ of Minnesota !

http://static.msi.umn.edu/rreports/2004/291.pdf

The above publication has extensive details of the numerical approach. The modeling includes surface tension force term represented by a linear/non-linear function of surfactant concentration using the continuum surface force (CSF) model. Nice read for developers and new onlookers.

How about DNS of droplets in a closed channel:

http://www.fusion.ucla.edu/neil/Publications/DirectSimulationOfFalling.pdf

The presentation below is litte off from the VOF topic: NEvertheless, you can see the application of VOF in inkJET print heads !!

http://www.coventor.com/pdfs/inkjet_design_for_web.pdf

A study on droplet deformation through a micro-fluidic orifice can be downloaded here.

http://anziamj.austms.org.au/ojs/index.php/ANZIAMJ/article/viewFile/953/791

Some VOF papers using different approaches (other than conventional VOF type)

1. Buoyancy driven droplets simulated using hybrid vof - LEVEL SET approach

http://ame-www.usc.edu/cf/Volterra2009/PROGRAM/PAPERS/Paper-62.pdf

2. Simulations of droplet flows using Lattice Boltzmann approach (just to make sure I do not shun LB approach ;)

http://staff.aist.go.jp/naoki-takada/fedsm2003-45166.pdf

3. A good article on jet breakup using particle method

http://www.nmri.go.jp/act/staff/k_shibata/Paper/SHIBATA_JetBreakup,%20.pdf

Shared Presentation of the Day: http://conferences.npl.co.uk/nmaet/downloads/presentations/costa.pdf
(Nice work VOF methods in Spray modeling !)

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