Sensitivity of flow visualization methods at low-density flow conditions

AIAA Journal ◽  
1965 ◽  
Vol 3 (4) ◽  
pp. 794-795 ◽  
Author(s):  
W. F. MERZKIRCH
1984 ◽  
Vol 146 ◽  
pp. 331-345 ◽  
Author(s):  
I. G. Bromilow ◽  
R. R. Clements

Flow visualization has shown that the interaction of line vortices is a combination of tearing, elongation and rotation, the extent of each depending upon the flow conditions. A discrete-vortex model is used to study the interaction of two and three growing line vortices of different strengths and to assess the suitability of the method for such simulation.Many of the features observed in experimental studies of shear layers are reproduced. The controlled study shows the importance and rapidity of the tearing process under certain conditions.


Author(s):  
A T Sayers

The phenomenon of reverse swing of the ball in a game of cricket is achieved by very few bowlers, and then only by those who seem able to bowl at speeds in excess of 85 mile/h. It also seems that reverse swing cannot be achieved at will. Rather, it is obtained perhaps by accident as much as by design, its inception being as much of a surprise to the bowler as to the batsman. This would suggest that the flow conditions pertaining to reverse swing are extremely marginal at best. This paper investigates the flow conditions required for reverse swing to occur and presents data describing the lift and drag on the ball. While some direct measurements are made on a cricket ball for comparison purposes, the flow over the ball is modelled through a 2.7:1 scale ratio sphere. This permitted relatively large lift and drag forces to be measured. The results define the range of Reynolds numbers and seam angles over which reverse swing will occur, as well as the corresponding forces on the cricket ball. Flow visualization is used to indicate the state of the boundary layer.


2020 ◽  
Vol 105 (4) ◽  
pp. 1035-1054
Author(s):  
Paolo Sassi ◽  
Youssef Stiriba ◽  
Julia Lobera ◽  
Virginia Palero ◽  
Jordi Pallarès

AbstractThe dynamics of three-phase flows involves phenomena of high complexity whose characterization is of great interest for different sectors of the worldwide industry. In order to move forward in the fundamental knowledge of the behavior of three-phase flows, new experimental data has been obtained in a facility specially designed for flow visualization and for measuring key parameters. These are (1) the flow regime, (2) the superficial velocities or rates of the individual phases; and (3) the frictional pressure loss. Flow visualization and pressure measurements are performed for two and three-phase flows in horizontal 30 mm inner diameter and 4.5 m long transparent acrylic pipes. A total of 134 flow conditions are analyzed and presented, including plug and slug flows in air–water two-phase flows and air–water-polypropylene (pellets) three-phase flows. For two-phase flows the transition from plug to slug flow agrees with the flow regime maps available in the literature. However, for three phase flows, a progressive displacement towards higher gas superficial velocities is found as the solid concentration is increased. The performance of a modified Lockhart–Martinelli correlation is tested for predicting frictional pressure gradient of three-phase flows with solid particles less dense than the liquid.


1979 ◽  
Vol 95 (1) ◽  
pp. 177-187 ◽  
Author(s):  
S. L. Gai

An experimental study of the flow past a thin finite length plate in a supersonic low density stream is reported. The paper discusses the corrections that are necessary for surface pressures measured under rarefied conditions. It is shown that the recent method of ‘orifice’ corrections due to Harbour & Bienkowski is versatile and reliable to use for both cold wall and insulated wall measurements. For the conditions of the experiment, the flow over the plate was found to be dominated by both leading-edge and trailing-edge interactions.


1973 ◽  
Vol 10 (10) ◽  
pp. 658-662 ◽  
Author(s):  
S. S. FISHER ◽  
D. BHARATHAN

1978 ◽  
Vol 20 (11) ◽  
pp. 2740-2744 ◽  
Author(s):  
V.M. Gol'dberg ◽  
B.V. Yarlykov ◽  
N.G. Paverman ◽  
Ye.I. Berezina ◽  
M.S. Akutin ◽  
...  

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