Begell House Inc.
Journal of Flow Visualization and Image Processing
JFV
1065-3090
1
3
1993
FLOW VISUALIZATION METHODS IN INTERSECTING DUCTS
159-170
10.1615/JFlowVisImageProc.v1.i3.10
Shinzaburo
Umeda
Department of Architecture and Civil Engineering, Fukuyama University
Wen-Jei
Yang
Department of Mechanical Engineering and Applied Mechanics University of Michigan, Ann Arbor, Michigan 48109-2125, U.S.A.
The flow in the intersecting region of two streams inside an X-shaped flow network is complex due to combined results of the ramming phenomena and the centrifugal force induced by the flow passage geometry. In order to determine the flow mechanisms, this study applies a combination of (1) the particle tracing method to observe streamlines, (2) the string method to visualize flow oscillations downstream from the intersecting region, and (3) the bubble tracer method to measure velocity vectors with the aid of particle image processing. Both the symmetric and asymmetric flows between the two branches are investigated. The intersecting angle and flow rates are varied to determine their effects on flow behavior. Flow oscillations in the downstream branches are found to be related to vortex formation.
AN OPTICAL METHOD FOR DETERMINING THE MENISCUS CHARACTERISTICS OF LIQUID FILMS FLOWING IN A GROOVE
171-179
10.1615/JFlowVisImageProc.v1.i3.20
M.
Khan
Institut de Génie Energétique, Université de Franche-Comté, Pare Technologique, 2, avenue Jean Moulin, 90000 Belfort, France
Philippe
Desevaux
Institut FEMTO-ST-UMR 6174, Département Energie, Université de Franche-Comté, Parc Technologique, Belfort, France
P. K.
Panday
Université de Franche Comté, Institut de Génie Energétique, 2 avenue Jean Moulin, 90000 Belfort, France
Jean-Pierre
Prenel
University of Franche Comte/CNRS 6174, Belfort, France
In this article, an optical investigation technique is described for visualizing the cross sections of flowing liquid films and determining the principal geometric characteristics of the meniscus (film height, equation of the meniscus, apparent contact angle, etc.). Flow visualizations are achieved by using a laser-induced fluorescence technique. Image processing then permits extraction of the meniscus curve and quantitative information. This technique is found to be useful to study the variations of the meniscus form for different groove geometries and mass flow rates.
FLOW VISUALIZATION AT THE LIQUID FREE SURFACE
181-188
10.1615/JFlowVisImageProc.v1.i3.30
M. D.
Cazacu
Faculty of Electrotechnics and Energetics, Department of Hydraulics and Hydraulic Machines, Polytechnic Institute of Bucharest, 77206, Romania
This article presents the methods used to visualize the laminar and turbulent free-surface liquid flow and to photograph the hydrodynamic spectra. The real images of laminar flows gave experimental evidence for the qualitative change of a viscous fluid flow for values of the Reynolds number Re = 1. The visual image of the turbulent flows has allowed an optimal geometric form design for fixed and moving bodies without boundary-layer separation.
A LASER-BASED, COMPUTER-AIDED, NONINTRUSIVE TECHNIQUE FOR QUALITATIVE AND QUANTITATIVE FLOW CHARACTERIZATION IN COWL-LIP CONFIGURATIONS OF VARIABLE GEOMETRY
189-209
10.1615/JFlowVisImageProc.v1.i3.40
Minel J.
Braun
Department of Mechanical Engineering, University of Akron, Akron, OH 44325
V. A.
Canacci
Department of Mechanical Engineering, University of Akron, Akron, Ohio 44325
L. M.
Russell
NASA-Lewis Research Center, Cleveland, Ohio 44135
This article has a twofold thrust: (1) The first is to present an application of a laser-based, computer-aided image processing technique for the full-field nonintrusive qualitative and quantitative evaluation of flow trajectories and velocities in a fluid; (2) the second is to apply this technique to the flow in a curved channel with a 180° turn, characteristic of inlet passages of the cowls of air-breathing aircraft engines. The method, based on the illumination of the test section with a planar laser sheet of light, allows microscopic or macroscopic surveillance of fluid flow across or along relatively large cross sections. The light-reflecting fluid tracers are tracked for relatively long (>1 s) periods of time. The procedure is Lagrangian in concept, and permits the identification and tracking of the same particle, thus facilitating construction of time-dependent trajectories, and calculation of time-dependent, rather than instantaneous, velocities and accelerations. The velocity maps can be used for construction of empirical heat transfer correlations as well as for verification of computer codes that predict the heat transfer rates in cowl geometries.
DEVELOPMENTS IN THE VISUALIZATION OF ROTOR WAKES USING THE WIDE-FIELD SHADOWGRAPH METHOD
211-233
10.1615/JFlowVisImageProc.v1.i3.50
Ashish
Bagai
Center for Rotorcraft Education and Research, Department of Aerospace Engineering, University of Maryland at College Park, College Park, Maryland 20742
Erwin P.
Moedersheim
Center for Rotorcraft Education and Research, Department of Aerospace Engineering, University of Maryland at College Park, College Park, Maryland 20742
J. Gordon
Leishman
Department of Aerospace Engineering, Glenn L. Martin Institute of Technology, University of Maryland, College Park, Maryland 20742
Some techniques are discussed that aid in the flow visualization of rotor tip vortices using wide-field shadowgraphy. The use of a beam splitter is shown to provide a particularly important enhancement to the method when large fields or angles of view are required. The optical characteristics of the strobe, observation screen, and recording film are also shown to be important for maximizing the shadowgraph contrast. Finally, theoretical predictions of the shadowgraph contrast for a series of compressible vortices are compared to experimental contrast results with a view to estimating the general velocity profile, viscous core radius, and viscous diffusion rate of the tip vortices.
APPLICATION OF REFLECTED GRID METHOD FOR EXAMINATION OF SMALL SURFACE DEFORMATION OF MOVING FLUID
235-238
10.1615/JFlowVisImageProc.v1.i3.60
V. I.
Bojarintsev
Institute for Problems in Mechanics, Vernadskogo, 101, Moscow, Russia
N. G.
Burago
Institute of Computer-Aided Design of the Russian Academy of Sciences, 19/18, 2nd Brestskaya, Moscow, 123056, Russia; Institute for Problems in Mechanics of the Russian Academy of Sciences, 101, Pr. Vernadskogo, Moscow, 119526, Russia
A. K.
Lednev
Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow, Russia
V. A.
Frost
Institute for Problems in Mechanics, Vernadskogo, 101, Moscow, Russia
A version of the reflected grid method for measuring small deformations of a liquid surface during its movement is suggested. The method is used for analysis of applicability to the simplest analytical methods for calculation of liquid surface deformations above a submerged, moving cylinder with bank axis normal to the moving direction.
VISUALIZATION BY COMPUTER GRAPHICS OF CONVECTIVE PLUMES DURING PROTEIN CRYSTAL GROWTH
239-252
10.1615/JFlowVisImageProc.v1.i3.70
Jer-Sheng
Lee
Department of Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, Michigan 48109
A series of numerical experiments have been conducted to investigate density gradient-induced solutal flow about growing lysozyme crystals. Numerical results are documented with the aid of computer graphics. Convective plumes are disclosed that vary during the growth process, confirming those observed experimentally as reported in the existing literature. The nature of these plumes is discussed.
MODEL-BASED VELOCITY ESTIMATION USING THE KALMAN FILTER
253-260
10.1615/JFlowVisImageProc.v1.i3.80
Kohtaro
Ohba
Department of System Information Science, Tohoku University, Aoba-ku, Sendai, Japan
Tadashi
Ishihara
Department of System Information Science, Tohoku University, Aramaki aza Aoba, Aoba-ku, Sendai, 980, Japan
Hikaru
Inooka
Department of System Information Science, Tohoku University, Aoba-ku, Sendai, Japan
In this article we propose a model-based method for estimating the velocities of unsteady viscous two-dimensional flow from a series of images. Assuming that the motion in the image plane is described by an affine transformation, we propose an adaptive Kalman filter algorithm that includes the identification of the dynamic model. Experimental results are presented to show the effectiveness of the proposed algorithm.