Journal of Visualization - Volume 4, issue 3

Authors: Ohta, J. | Mayinger, F. | Feldmann, O. | Gebhard, P.

Article Type: Research Article

Abstract: The present paper describes a method for evaluating images of a bubbly flow in stirred aerated tanks which are typical when pulsed laser holography is applied as the measuring technique. Features of the brightness histograms of reconstructed bubble images are discussed. A procedure is presented to evaluate the bubble images taken from a reconstructed hologram in order to determine the center of gravity of the bubble image. Double pulsed holograms were taken to measure bubble velocities …and diameters simultaneously. In this case, overlapping bubble images are sometimes observed in the reconstruction. This significantly impedes the evaluation of the characteristics of the bubbles. Thus, an algorithm is presented in this work to distinguish between single and overlapping bubble images and to separate the overlapping bubble image in a two-dimensional image for a bubbly flow at low void fraction recorded from double pulse holograms. This algorithm was confirmed to be effective if the bubble images are extracted from the entire image. Show more

Keywords: image processing, overlapping bubble image, short time holography

Citation: Journal of Visualization, vol. 4, no. 3, pp. 285-298, 2001

Authors: Grant, I.

Article Type: Research Article

Abstract: The 9th Millennium International Symposium on Flow Visualization (9misfv) was held in Edinburgh, Scotland from the 22nd August to the 25th August 2000. The symposium attracted, by a significant amount, the largest number of participants in the history of the symposium series. A total of 396 presentations were made at the symposium. These were distributed through 74 technical sessions covering a full spectrum of topics in 373 oral presentations and 23 poster presentations. The symposium commenced …with an opening address and welcome to delegates by the Symposium Chairman, Professor I. Grant. The technical presentations commenced with Professor G. M. Carlomagno giving the invited Leonardo da Vinci Memorial Lecture entitled "Infrared Thermography: a Particular Surface Flow Visualization Technique." Each day of the meeting commenced with an invited Keynote lecture, given in plenary session, by a recognised authority in the respective area. These were, in order of presentation, Professor Toshio Kobayashi "High Performance Computation and Visualization of Fluid Flows," Dr. Juergen Kompenhans "Qualitative and Quantitative Visualization of Wake Vortices in Industrial Test Facilities," Professor Jim Whitelaw "Aspects of Unsteady Combustion" and Professor Mory Gharib "On the Role of Flow Visualization in the Understanding of Cardiovascular Fluid Dynamics: from da Vinci to Harvey." During the symposium two awards were made to distinguished scientists. These were the Leonardo da Vinci award to Professor Giovanni Carlomagno and the Asanuma award to Professor Wolfgang Merzkirch. Show more

Keywords: flow visualization, combustion, channel flows, cavity flows, bluff bodies, aircraft, acoustics, Computational Fluid Dynamics (CFD), cylinders, droplet break-up, electrodynamics, fluidics, holography, infrared thermography, interferometry, jets, liquid crystals, low Reynolds number flows, medical, multiphase flows, natural convection, numerical visualization, particle image velocimetry (PIV), particle tracking velocimetry (PTV), porous media flows, rotating fluids, Schlieren, supersonic flows, turbulence, unsteady flows and instability, vortices

Citation: Journal of Visualization, vol. 4, no. 3, pp. 299-304, 2001