0214 Flow Visualization for Three-Dimensional Structures Superimposed on the Vortex Shed from a Circular Cylinder

2015 ◽  
Vol 2015 (0) ◽  
pp. _0214-1_-_0214-4_
Author(s):  
Tomoki SUZUKI ◽  
Masanori MATSUMURA
1990 ◽  
Vol 211 ◽  
pp. 157-182 ◽  
Author(s):  
M. Tatsuno ◽  
P. W. Bearman

The structures of the flow induced by a circular cylinder performing sinusoidal oscillations in a fluid at rest are investigated by means of flow visualization. The experiments are carried out at Keulegan–Carpenter numbers between 1.6 and 15 and at Stokes numbers between 5 and 160. Above a certain value of Keulegan–Carpenter number, depending on the Stokes number, some asymmetry appears in the flow separation and the associated vortex development behind the cylinder. The two vortices that are developed in a half cycle differ in strength and may be convected in different directions. This results in a fascinating set of flow patterns. Eight different regimes of flow can be identified within the ranges of Keulegan–Carpenter number and Stokes number studied. Furthermore, most of the resulting flows show a three-dimensional instability along the axis of the cylinder. Measurements of the wavelength of these disturbances are presented.


Author(s):  
Theodore J. Heindel ◽  
Terrence C. Jensen ◽  
Joseph N. Gray

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will be presented. When two X-ray sources and detectors simultaneously acquire images of the same process or object from different orientations, stereographic imaging can be completed; this type of imaging will be demonstrated by trickling water through packed columns and by absorbing water in a porous medium. Finally, local time-averaged phase distributions can be determined from X-ray computed tomography (CT) imaging, and this will be shown by comparing CT images from two different gas-liquid sparged columns.


2011 ◽  
Vol 23 (6) ◽  
pp. 064106 ◽  
Author(s):  
Nicolas Kanaris ◽  
Dimokratis Grigoriadis ◽  
Stavros Kassinos

1984 ◽  
Vol 106 (4) ◽  
pp. 390-398 ◽  
Author(s):  
J. R. Koseff ◽  
R. L. Street

A synthesis of observations of flow in a three-dimensional lid-driven cavity is presented through the use of flow visualization pictures and velocity and heat flux measurements. The ratio of the cavity depth to width used was 1:1 and the span to width ratio was 3:1. Flow visualization was accomplished using the thymol blue technique and by rheoscopic liquid illuminated by laser-light sheets. Velocity measurements were made using a two-component laser-Doppler-anemometer and the heat flux on the lower boundary of the cavity was measured using flush mounted sensors. The flow is three-dimensional and is weaker at the symmetry plane than that predicted by accurate two-dimensional numerical simulations. Local three-dimensional features, such as corner vortices in the end-wall regions and longitudinal Taylor-Go¨rtler-like vortices, are significant influences on the flow. The flow is unsteady in the region of the downstream secondary eddy at higher Reynolds numbers (Re) and exhibits turbulent characteristics in this region at Re = 10,000.


2021 ◽  
Vol 33 (3) ◽  
pp. 479-487
Author(s):  
Wei-wen Zhao ◽  
Chun-hui Ma ◽  
De-cheng Wan ◽  
Yi-qian Wang

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