Fluid dynamics is physics? not engineering? cool :-)

If you open Physics Today, December 2005 issue, you’ll find out an excellent artcile about Ludwig Prandtl’s Boundary Layer theory by John D Anderson Jr. Turbulent Boundary Layer is our “favorite” turbulent flow (see below the work we’ve done in the turbulent boundary layer flows, or follow the links to the authors, Uri, Roi or Alex)

We are proud to be a humble member of the experimental fluid mechanics community, working both in Physics and Engineering areas.

For those who cannot afford to subscribe for this journal or those who’s in engineering and never read this magazine, i made an unprofessional, ugly scan of the article. Please, use it only for the personal reading and do not distribute it. All the rights are reserved to Physics Today.

URAPIV users from the University Miguel Hernandez of Elche (Spain)

Our recent user, Jose Manuel Pedrero Canovas from University of University Miguel Hernandez of Elche (Spain) has provided us with very nice overview of his research and the results of URAPIV. He wrote us:

Here I send you some results of my experiments. As you can see, I use ‘overlapping’ to get more measurement points.

I compare the theoretical curve with the values obtained for each volume (liters/hour), as well as recording frequency (fps) and values of ITT and SPC. They are very good and these are the initial experiments to be able to extrapolate the work method to others in which we do not have theoretical solution.

We’ll continue in contact and thaks for the help!

The results look like:

in which we can observe a typical profile of an anular flow in a tube with an inner axis. We helped a bit with customizing the old Matlab version of URAPIV (for Matlab 6.5 or R13) and TIFF images that looked like this one:

obtained in the following facility:

Technorati, again

Technorati [more info about the site] has registered velocimetry tag. Amazingly cool, it points to URAPIV (through the openscience.org).

OpenSciense on URAPIV

It’s great to see that we’re noticed by the OpenScience Project. We quote:

“This is cool: URAPIV is an open source Matlab Toolbox for Particle Image Velocimetry (PIV) analysis. Particle Image Velocimetry is a planar, non-intrusive, optical imaging measurement technique that allows for two-dimensional, high-resolution velocity vector fields of laminar and turbulent flows. URAPIV is also a blog about the software.”

http://www.openscience.org/blog/wp-trackback.php?p=141

Stereoscopic PIV system, Multiphase Flow Laboratory @ Technion

The image is of the stereoscopic PIV system from TSI Inc. that we used in our research in the Multiphase Flow laboratory under supervision of Prof. Gad Hetsroni. The research was performed in a flume (water flow in an open-channel) that was made of glass (a part of it you can see in the image).

During the study we compared URAPIV to Insight (the software from TSI) that was version 3.4 at that time. We found excellent agreement between the two results. It is not clear who should be actually happy about the output. TSI has upgraded their software to Insight 3G. This product will include a large portion of Matlab (not open source, unfortunately) and it seems to be the direction. Their competitors, Dantec Dynamics and LaVision, among others, also incorporate Matlab in the analysis of the PIV realizations.

On the right side of the image above one can see the outlet tank and below you can see how it looks when we put 20 parts-per-million (ppm) of surfactant (surface active agent). It is only 80 grams of Agrimul PG 2062 (bio-degradable surfactant from Alkyl Polyglycosides family) but see what it did to our lab

Another publication, this time in Civil Engineering

Samer Sadek, Magued G. Iskander, and Jinyuan Liu, have published “Accuracy of Digital Image Correlation for Measuring Deformations in Transparent Media” in J. Comp. in Civ. Engrg., Volume 17, Issue 2, pp. 88-96 (April 2003). The researches used URAPIV as the basis for their Digital Image Correlation method.

URAPIV in Plasma Research

Yes, that’s true. Now, for the first time we (simple engineers :-)) are useful for the High Physics. The researcers from CASPER (Center for Astrophysics, Space Physics, and Engineering Research) Baylor University, TX, USA have used our open source code in Matlab and our ideas to analyze dust particles in plasma. Read their preprinted version on ArXiV, or find it yourself as
“Digital Imaging and Analysis of Dusty Plasmas”, C.M. Boesse, M.K. Henry, T.W. Hyde and L.S. Matthews, accepted for publication in Advances in Space Research, 2003.

URAPIV and X-Ray tomography

Yes, that’s right. X-Ray tomography is impossible without URAPIV Seriously, we are glad to see that our code is useful in the broad range of research areas. This time it is used in biology. X-RAY TOMOSYNTHESIS ELASTOGRAPHY is a name of the technique that found URAPIV applicable. Follow the [link] to the poster in PDF format by researchers (a cooperative research of Biomedical, Aerospace and Medical scientists) from the Boston University.

URAPIV in action

In 2004, a group of researchers from Netherlands and Ireland has used URAPIV source for the optical measurements in two-phase bubble flows in a convective flow. [abstract] of their paper in Measurement Sciense and Technology. You can obtain the paper also following its DOI: 10.1088/0957-0233/15/6/N01

It is interesting that the first author is Victor Chan (from Delft University) who had designed (though not updated very much recently) very informative website, devoted for the optical measurements in fluids: www.holomap.com

The same group has published in Proc. 11th International Symposium on Applications of Laser Techniques to Fluid Mechanics:

Y.M.C. Delauré, V.S.S. Chan and D.B. Murray Department of Mechanical and Manufacturing Engineering, Trinity College, Dublin 2, Ireland presented Bubble Wake Interaction with Convective flow from a heated vertical flat plate.

PIV application

Very interesting PIV application - an experimental investigation of lizards running on water (!). Cross-post from http://cerebralvomits.blogspot.com/. The original article is available from Proceedings of National Academy of Sciences, USA