Experimental Study of Three Dimensional Vortex Structure at Low Velocity Ratio of Coaxial Jet

2020 ◽  
Vol 2020 (0) ◽  
pp. OS03-28
Author(s):  
Fujio AKAGI ◽  
Taiga MIYAZAKI
Keyword(s):  
Experimental Study ◽  
Vortex Structure ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Low Velocity

scholarly journals Experimental Study on the Flow Characteristics of Streamwise Inclined Jets in Crossflow on Flat Plate

1992 ◽  
Author(s):  
Sang Woo Lee ◽  
Joon Sik Lee ◽  
Sung Tack Ro
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Flow Structure ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Slight Variation ◽  
Injection Angle ◽  
Large Velocity ◽  
Vorticity Dynamics

Experimental study has been conducted to investigate the flow characteristics of streamwise 35° inclined jets, injected into a turbulent crossflow boundary layer on a flat plate. Flow is visualized by schlieren photographs for both normal and inclined jets to determine the overall flow structure with the variation of the velocity ratio. Three-dimensional velocity field is measured for two velocity ratios of 1.0 and 2.0 by using a five-hole directional probe. The visualization study shows that a slight variation of the injection angle produces a significant change in the flow structure. It is recognized that the jet flow is mainly dominated by the turbulence for a small velocity ratio, but it is likely to be influenced by an inviscid vorticity dynamics for a large velocity ratio. Such a trend prevails in the streamwise inclined injection, compared with the normal injection. A pair of bound vortices accompanied with a complex three-dimensional flow is present in the downstream region of the jet exit as in the case of the normal injection, although its magnitude and range are different, and the strength of the bound vortex is strongly dependent on the velocity ratio. The interface between the jet and the crossflow is identified from the vorticity distribution.

Flow Characteristics of a Three Dimensional Bluff Body With a Single Rotating Cylinder

2012 ◽  
Author(s):  
James R. Bell ◽  
David Burton ◽  
Damien McArthur ◽  
John Sheridan
Keyword(s):  
Bluff Body ◽  
Aerodynamic Drag ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Rotating Cylinder ◽  
The Body ◽  
Surface Velocity ◽  
Cylinder Surface ◽  
Low Velocity ◽  
Freestream Velocity

This work investigated the application of a rotating cylinder to the upper leeward edge of a three dimensional bluff body in ground proximity. Aerodynamic drag measurements, base pressure contours and wake velocity profiles were obtained in a closed jet wind tunnel for Reynolds Numbers in the range of approximately 220,000 to 660,000. The cylinder of diameter 0.1H was mounted on the upper edge of the leeward face of the body. The ratio of cylinder surface velocity to freestream velocity was varied from 0 to 2.0. A computational model of the geometry was developed and results are presented for various velocity ratios and cylinder diameters. The results of this work demonstrated that, even at low velocity ratios, the cylinder rotation has a large effect on the flow structures in the body wake region. A large downwash is observed that creates two large counter-rotating vortices and a resultant significant increase in drag. The aerodynamic drag changes are presented as a function of velocity ratio and are shown to be Reynolds Number insensitive over the range tested. Aerodynamic drag was shown to increase with increasing velocity ratio over the velocity ratio range 0.25 to 2.0.

Experimental Study on the Flow Characteristics of Streamwise Inclined Jets in Crossflow on Flat Plate

1994 ◽  
Vol 116 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Sang Woo Lee ◽  
Joon Sik Lee ◽  
Sung Tack Ro
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Flow Structure ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Three Dimensional Flow ◽  
Injection Angle ◽  
Large Velocity ◽  
Vorticity Dynamics

Experimental study has been conducted to investigate the flow characteristics of streamwise 35 deg inclined jets, injected into a turbulent crossflow boundary layer on a flat plate. Flow is visualized by schlieren photographs for both normal and inclined jets to determine the overall flow structure with the variation of the velocity ratio. A three-dimensional velocity field is measured for two velocity ratios of 1.0 and 2.0 by using a five-hole directional probe. The visualization study shows that the variation of the injection angle produces a significant change in the flow structure. It is recognized that the jet flow is mainly dominated by the turbulence for a small velocity ratio, but it is likely to be influenced by an inviscid vorticity dynamics for a large velocity ratio. Such a trend prevails in the streamwise inclined injection, compared with the normal injection. A pair of bound vortices accompanied with a complex three-dimensional flow is present in the downstream region of the jet exit as in the case of the normal injection, although its magnitude and range are different, and the strength of the bound vortex is strongly dependent on the velocity ratio. The interface between the jet and the crossflow is identified from the vorticity distribution.

scholarly journals Seismic Structure of Local Crustal Earthquakes beneath the Zipingpu Reservoir of Longmenshan Fault Zone

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Haiou Li ◽  
Xiwei Xu ◽  
Wentao Ma ◽  
Ronghua Xie ◽  
Jingli Yuan ◽  
...  
Keyword(s):  
Fault Zone ◽  
Three Dimensional ◽  
P Wave ◽  
The Tibetan Plateau ◽  
Seismic Structure ◽  
Infiltration Depth ◽  
Low Velocity ◽  
Longmenshan Fault Zone ◽  
Velocity Models ◽  
Longmenshan Fault

Three-dimensional P wave velocity models under the Zipingpu reservoir in Longmenshan fault zone are obtained with a resolution of 2 km in the horizontal direction and 1 km in depth. We used a total of 8589 P wave arrival times from 1014 local earthquakes recorded by both the Zipingpu reservoir network and temporary stations deployed in the area. The 3-D velocity images at shallow depth show the low-velocity regions have strong correlation with the surface trace of the Zipingpu reservoir. According to the extension of those low-velocity regions, the infiltration depth directly from the Zipingpu reservoir itself is limited to 3.5 km depth, while the infiltration depth downwards along the Beichuan-Yingxiu fault in the study area is about 5.5 km depth. Results show the low-velocity region in the east part of the study area is related to the Proterozoic sedimentary rocks. The Guanxian-Anxian fault is well delineated by obvious velocity contrast and may mark the border between the Tibetan Plateau in the west and the Sichuan basin in the east.

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