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 coalescence0 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 !)

I will try adding some more videos / pictures on VOF modeling in the upcoming posts.

Presentations on Multiphase Flow

Its always nice to keep a directory loaded with presentations that contain valuable information such as modeling basics, some applications, discussions that we come across quite frequently. Sometimes, when I run out of ideas as to what kind of modeling should I consider or concerns regarding the physical approximations, an quick glimpse of some presentation slides provide me with the much needed break.

I am trying to load the blog with some presentations that I came across recently

An workshop conducted in Michigan State on MP flows with discussions and applications is available here

http://www.iihr.uiowa.edu/~istue/Workshop_michigan state.ppt

CFD usage in particle separation etc (from Alstom site)

http://www.chalmers.se/am/SV/forskning/forskningsavdelningar/stromningslara/siamuf/seminarium-arkiv/seminarium-maj-2006/downloadFile/attachedFile_9_f0/CDF_usage_in_Alstom_ECS.pdf?nocache=1202896312.71

the above site clearly shows the industrial CFD procedures - what the industrial CFDers really want to look at etc..its more of a perspective based presentation ..not too much tech :)

A nice presentation by Dr. Pannala (MFIX guy)

http://www.caer.uky.edu/presentations/seminar-Pannala-CAER2009.pdf

Another work by Dr. Syamlal - (The guy from Syamlal - Obrien model in Gas-Solid flows)
http://www.rpsea.org/attachments/contentmanagers/1932/Madhava.Syamlal.pdf

A general publication on mixing layers and particle dispersion : www.lc.leidenuniv.nl/lc/web/2006/191/presentations/Lakehal1.ppt

An presentation on Solid phase systems (transport of solid particles) http://www.netl.doe.gov/publications/proceedings/09/mfs/11%20P%20Chapman%2042209.pdf

CFD code validation study from Canada: http://www.acfda.org/docs/gtc_presentation_agranat.pdf
(has some nice modeling part inside !!)

CFD Presentation on multi-poly-dispersed flows : http://www.cfdoil.com.br/pdf/presentations/18_2_1445.pdf

 CFD in Bio-Respiratory work: www.imagwiki.org/mediawiki/images/6/61/APS2006.ppt 


Multiphase CFD applications in Fluidized beds (a nice one ..I will probably use this later ?)
http://www.aka.fi/Tiedostot/Tiedostot/ENERGIA/Vuosiseminaari%202009/Timo%20Hypp%C3%A4nen_Multiphase%20fluidized%20bed%20processes.ppt.pdf 

CFD multiphase simulations : Cavitation Modeling Papers

Many multiphase CFD studies such as those of bubbly flows find extensive industrial applications which in turn induces higher interest among researchers to push for achieving higher level of details. It wouldnt be wrong if we call 'cavitation' as one of the most sought physical phenomena involving multiphase flow that has attracted so many academicians and industrial research fellows all around the world.


Cavitation, for its part, find applications right from your house pump to complicated industrial mixing devices, such as spray applicators, injectors in automotive units, in ultrasonics industry (sono-luminescence) to just quote a few.

The interest has been so over whelming...that conferences among the world have started dedicating separate sessions on cavitation - experiments, numerical simulations, modeling...

Having worked with this unique multiphase flow application myself, I have often wondered how everytime I dig into the fundamental nature of this process, it unveils a completely different nature that keeps me wandering around the topic..so far, having done some serious numerical computations (using incompressible, compressible, analytical modeling ..just not experiments yet...well wait..i did produce cavitation using airfoils in a simple lab experiment..nope that doesnt count? ), I thought this special topic requires some nice postings so that people can find it useful to reference and compare their own work with peers.


Several colleagues have come over to my desk inquiring .."hey, do you have any information / notes concerning bubble dynamics? " and i go, wow..there is an entire book available on this topic ..for FREE !

The cavitation and bubble dynamics book by Dr. Brennan should be your first reference to cite and read !

http://caltechbook.library.caltech.edu/1/

The book is available as html , pdf etc...Nice images of cavitating process - vortex type, chain, cloud cavitation are alllll available !!

1. Find multiphase modeling of super cavitating flows here: Publication text by Kunz et al.

http://ftp.rta.nato.int/public//PubFullText/RTO/EN/RTO-EN-010///EN-010-13.pdf

2. On Propellar sheet cavitation:

http://www.ichd2010.org.cn/ICHD-EC/ICHD/eighth/papers/ICHD2008_2B-03_53.pdf

http://www.marinepropulsors.com/proceedings/TB4-1-Salvatore%20-%20Propeller%20Cavitation%20Modelling%20by%20CFD%20-%20Results%20from.pdf

3. By the way, I find a complete list of papers to follow, read, quote / reference and use for my own work from the listing of CAV2001 symposium !!

http://cav2001.library.caltech.edu/view/subjects/

Its free for download based on category (within cavitation ofcourse !) : bubbly flows, erosion, turbomachinery, vortex type...

4. Cavitation in Pumps:

http://turbolab.tamu.edu/uploads/files/papers/p23/P23Lec06.pdf

http://khzs.fme.vutbr.cz/iahrwg2009/docs/D3.pdf

5. Cavitation Simulation : Shock Emission

http://www.lhm.mw.tu-muenchen.de/gd/veroeffentlichungen/8th%20ETC%20Graz%202009.pdf

6. Dispersion in Cavitating Flows

http://proceedings.europeanmixing13.org/data/Baldyga_et_al.pdf

7. Dr. Kunz's work on Pump Cavitation

http://www.personal.psu.edu/rfk102/PROF/ASMEFEDSM01/finalpaper.pdf

8. Here is an article on Vortex Cavitation !

http://www.hitachi-pt.com/products/si/pump/pdf/pump_09.pdf

If you notice the commercial CFD vendors, here is my take on their release versions:

Everytime, a new release is made by the software...from version v.x to v.y etc, notice that, on most occasions, there is some type of enhancement to cavitation prediction claimed by the software developers! Now, that should shed a lot of light on how much the industrial expectation out of these vendors to predict most accurate results !!! Experimentally, work on cavitation has been quite extensive as well. However, I fail to report their stand owing to my strong belief in numerical modeling ;)

Some other cavitation models other than the conventional (familiar ones) can be accessed here

a recent article on tracking cavitation as a scalar: doi:10.1016/j.apm.2008.02.005 

Homogeneous equilibrium modeling approaches:

1. http://ta.twi.tudelft.nl/users/vuik/Heu00VW.pdf

2. http://homepages.cae.wisc.edu/~rutland/research.dir/nozzle_cavitation.dir/sae971597.pdf (Dr. Schmidt's work)

3. Found one in the cav2001 symposium : http://cav2001.library.caltech.edu/257/00/cav2001.pdf

4. Found another one but not able to link it from ICLASS 2006 based on HEM

Title: "Computational investigation of cavitating injectors flows using Homogeneous Equilibrium Model supplemented with a pressure correction equation" using openFOAM
Paper 06-087, ICLASS 06, Kyoto, Japan, 2006.

While looking for cavitation and corrosion, I found this book link: useful i guess

http://www.corrosioncenter.ohiou.edu/nesic/papers/FullText/book-5.pdf


Happy Cavitating !!!!

CFD Publications : Download, Share and Reference

On several occasions, I come across listing of publications/ conference papers available for free download for educational purpose and would try to mark the website for future reference. But, however, in time, I lose track of such nice websites and the link to those papers I wanted to download and read then. This has been a constant challenge to me and I hope, by creating this blog, I can put several listings on lectures / journals etc together and make them freely accessible to others.

Papers from NETL - the Energy Lab workshop on multiphase flow science (Fundamentals of Multiphase Flow) is available for download

http://www.netl.doe.gov/publications/proceedings/09/mfs/index.html

The NETL workshop has some exciting papers on transport phenomena such as fluidisation CFD, discussions regarding MFIX, multi-scale CFD simulations ..to count a few.

Publications from the Institue for corrosion and multiphase technology can be found at

http://www.corrosioncenter.ohiou.edu/publications.htm

The Ohio site has listings of patents - particularly in the area of slug flow, sediment transport etc. Interested people can take a look at these drafts at

http://www.corrosioncenter.ohiou.edu/Patents.htm

Dr. Pai's site has some nice listings on modeling of droplet dispersion, DNS, LES, Sprays etc..

http://www.stanford.edu/~mpai/publications.html (only few papers are available for download)

Several part of his work such as spray modeling (DNS, LES etc) are very famous and definitely be in my reference list while publishing in these areas.

Also, the website http://www.cfd.com.au/index.html provides a comprehensive list of CFD conference proceedings from 1997 to 2008 !!! Publications of varying interest in the CFD area such as Electromagnetic processes, Mixing and turbulence, power generation, flash melting, numerical methods, fluidised beds, stirred tanks, casting, combustion / particle flows are available by categories. One can choose the papers to download by organizing by authorship as well.

For example, Papers on Mixing and Turbulence from 1997 CFD conference proceedings can be downloaded from

http://www.cfd.com.au/cfd_conf97/mixing_and_turbulence.htm

Download the proceedings of openSource CFD International Conference 2008 from here

http://www.opensourcecfd.com/conference2008/index.php?option=com_content&task=view&id=3&Itemid=30

Download complete listings of Univ Iowa based researcher Dr. Becker's papers on phase change modeling !!

http://www.engineering.uiowa.edu/~becker/documents.dir/

Also, http://www.engineering.uiowa.edu/~becker/phasefield.htm provides the list directly.

Dr. Kirby's work (univ of Delaware) can be obtained from http://chinacat.coastal.udel.edu/papers/

The website http://www.scansims.org/sims2001/SIMS2001/Papers/  can be used to download publications from the 42nd conference on simulation and modeling organized by the Scandinavian Simulation Society. The complete list organized by session is available for download.

More archival publication listings (complete from 1998 - present) of the society of petroleum engineers can be accessed through  http://www.spe.org/jpt/print/archives/

The publication has nice discussions ranging from energy to technical issues in modeling / simulation (Principles of Modeling and Simulation: A Multidisciplinary Approach, Theory of Modeling and Simulation, Second Edition).

I will be adding some more listings for easy access to fellow CFDers and Fluid dynamics researchers :)

CFD Simulations: Matlab Usage / Coding / Applications ...

Over time, there has been increasing discussions on whether or not other commercial softwares be used to program CFD and post process calculations...for example: use of Matlab (Matlab: A Practical Introduction to Programming and Problem Solving). In this blog, I will try to post links and articles - which uses matlab for CFD (/ general numerical) calculations.

Website maintained in the mech and material science dept., oregon

http://web.cecs.pdx.edu/~gerry/class/ME448/codes/

has some nice listing of matlab codes for 1D, 2D finite volume based calculations !! A nice start for beginners and others who look to use Matlab for their scientific needs.

Discussions in the good groups on whether or not Matlab could be used in the CFD world was interesting:

http://groups.google.com/group/comp.soft-sys.matlab/browse_thread/thread/09dae3365cd4fa39

How about some nice shallow water modeling (CFD) using matlab: The file is available for download from the matlab central server

http://www.mathworks.com/matlabcentral/fileexchange/17716

I found a paper on

1. CFD graphical interface using Matlab: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.90.3658&rep=rep1&type=pdf

2. 2D Airfoil optimization using CFD (matlab based) : http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.108.854&rep=rep1&type=pdf

3. Thesis work: CFD program to model pressure distribution of melt flow using Matlab

http://www.me.umn.edu/~td/Lewandowski-Thesis.pdf

4. Discussions on SIMPLE algorithm in Matlab

http://www.mathworks.de/matlabcentral/newsreader/view_thread/246199


In the pre-processing segment, the use of matlab has been extensive as well:

1. DistMesh: a simple mesh generator using matlab can be found here (http://www-math.mit.edu/~persson/mesh/) . Nice application for unstructured triangular and tetrahedral meshes.

2. Gridgen: a matlab based orthogonal grid generator to construct orthogonal curvilinear grids is available here.

http://woodshole.er.usgs.gov/operations/modeling/gridgen/

The gridgen site has tutorials and details for download and installation.

3. The cornell based QMG package does finite element mesh generation in two and three dimensions

http://www.cs.cornell.edu/home/vavasis/qmg-home.html

For some fundamental functions usage and programming for coding the entire CFD structure or in parts (pre / post processing) these books may be helpful.

1. MATLAB Programming for Engineers
2. An Introduction to Programming and Numerical Methods in MATLAB
3. Engineering Analysis: Interactive Methods and Programs with FORTRAN, QuickBASIC, MATLAB, and Mathematica

Multiphase Modeling: Eulerian-Eulerian simulations / applications

Simulation of multi-fluid flows (Multiphase Phenomena and Cfd Modeling and Simulation in Materials Processes) are often complex and requires complex mathematical treatment at the interfaces defining the fluid boundaries. Modeling the interfacial effects have been the core research for multi-fluid researchers. Often, a typical multi-scale phenomena that needs to be simulated is broken down into different zones identified by the acting scales and then "modeled" based on the acting physics. The work is still on-going but has definitely met with a lot of success and is often the default setting in major industrial practices [Comparison of different model approaches for the simulation of multiphase processes [An article from: Atmospheric Environment]).

I have come across the smash-project some time ago and thought this post on multifluid modeling will get a good facelift starting with a decent description of this modeling project.

http://ralyx.inria.fr/2006/Raweb/smash/uid7.html

As stated in their website: "Smash is a common project between INRIA and the University of Provence. The main topic of our project focuses on problems related to mathematical and numerical modeling of heterogeneous flows such as multiphase media, granular materials or reactive flows with mass transfer" presents a good description of the team goal. The website contains in-depth details of the applied methods (with assumptions yes..., mathematical treatment and aspects of parallel / grid computing)

Theses work following this project are listed here

http://ralyx.inria.fr/2006/Raweb/smash/uid70.html

and publication description: http://ralyx.inria.fr/2006/Raweb/smash/bibliography.html

With reference to multi-fluid flow modeling and numerical analysis, the work of the Center for Risk studies and safety is a must read.

Their website http://www.crss.ucsb.edu/ gives a complete picture of the their code MUSIC and associated publications and presentations made at major conferences and journals.

The link: http://www.crss.ucsb.edu/music/LEVEL0/ lists all their publications and reports...i had bookmarked their information several years back and continue to look at their recent development in numerical analysis.

The papers (on multifluid analysis) from the 6th int. conf on CFD (Norway) can be downloaded from

http://www.sintef.no/Projectweb/CFD2008/Papers-from-CFD2005/Multifluid-flow-analyses/

I noted some papers which can be used for referencing and for extracting some finer numeric details while performing multifluid calculations include

1. Simulation of flow behavior in bubble column:
http://www.sintef.no/project/CFD2008/CFD2005_papers/36_Zhang_Deen_Kuipers.pdf

2. CFD modeling in gas fluidized beds

http://www.sintef.no/project/CFD2008/CFD2005_papers/42_Yusuf_Melaaen_Mathiesen.pdf

(Take a look at another papers on CFD work on fluidized bed:
http://www.scansims.org/sims2001/SIMS2001/Papers/Paper01-%20B.Halvorsen%20(SIMS_BrittHalvorsen).doc)


3. 2D/3D investigations of dispersion and mass transfer coefficients in a Eulerian multifluid model

http://www.sintef.no/project/CFD2008/CFD2005_papers/53_Guenther_Breault.pdf

4. Evaluation of num methods for solving population balance eqn

http://www.sintef.no/project/CFD2008/CFD2005_papers/45_Dorao_Jakobsen.pdf

There are several other nice papers available in the area of Environment/Combustion, fundamental methods and validation, some aspects of industrial CFD, oil and gas systems..

Nice application : Cyclone separators (gas-liquid) type

http://tustp.org/publications/cfd_bubble_carry_under_98.pdf

I normally tend to download the entire directory and keep it in my repository for future references ..even if i dont need them now. These papers are worth looking at and most of the time saves us lot of times when modeling similar to these are required to be computed.

For all those looking at ( or working with ) multifluid methods, the following paper can definitely be considered as a bible ;)

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA410325&Location=U2&doc=GetTRDoc.pdf

Also, Kunz's paper: http://www.personal.psu.edu/rfk102/PROF/JCPpaper/jcpfinal.pdf

Other publications of interest

1. http://www.cimec.org.ar/ojs/index.php/mc/article/view/2827/2764 (CFD in Trickle bed reactor)

2. http://www.sintef.no/units/matek/2420/242025/ (Nice presentations on multifluid - granular flow etc!)

3. http://www.opensourcecfd.com/conference2008/media/proceedings/OSCIC-08_CarneiroJoao.pdf (openFoam based polydispersed flow modeling)

4. http://www.cfd.com.au/cfd_conf99/papers/030LIOV.PDF (free surface flows in metallurgical vessels)

5. http://www.nea.fr/html/nsd/reports/2007/nea6298/Technical_Session_B1_Advanced_Reactors/7-Kanghs_PWR.pdf (CFD : subcooled flow under high steam flux)

I would post some more research articles that is focused on 1. Numerics 2. Applications.

Some nice books for reference on MP flows validation and application:
1. Improvements in multiphase flow measurement.(Measurement Matters)(Column): An article from: Pipeline & Gas Journal
2. Fundamentals of Multiphase Flow
3. Computational Methods for Multiphase Flow
4. Multiphase Flow Dynamics 3

If you have any queries or publications that you think should be posted in this regard, kindly let me know. Sharing the knowledge is the only way to excellence !!

CFD Simulations (Animations ?)

I came across nice animations of free surface flows from the CFD team of Dr. Veldman (http://www.math.rug.nl/~veldman/)

The familiar droplet bouncing problem treated by the CFD group is shown below.




The work on 3D dambreaking problem is shown below.



The website for downloading some impressive videos on Free surface flows can be found at
http://www.math.rug.nl/~veldman/cfd-gallery.html


Sample simulations of Free surface modeling is also available in the Univ Iowa website
http://www.engineering.uiowa.edu/fluidslab/gallery/ani-num-sim.html

A sample video downloaded from their site is posted here.

Flow over a Weir



An fire simulation is also available in the groups' site







Materials on : An introduction to CFD is available in their main page
http://www.engineering.uiowa.edu/%7Efluids/Lab/CFD_lecture_2003.ppt

Other handouts can be downloaded from
http://www.engineering.uiowa.edu/fluidslab/numsim/handouts.html


An virtual album of fluid flow can be viewed at : http://www.featflow.de/album/contents.html

These videos are copyrighted and have been posted here for educational purposes only. You can contact the respective institutions for further information.