scholarly journals Similitude of Air Entrainment at Vertical Circular Plunging Jets

2002 ◽  
Author(s):  
Hubert Chanson ◽  
Shin-Ichi Aoki ◽  
Ashabul Hoque
Keyword(s):  
Scale Effects ◽  
Air Entrainment ◽  
Air Bubble ◽  
Bubble Dispersion ◽  
Jet Impact ◽  
Scale Models ◽  
Bubble Entrainment ◽  
Plunging Jets ◽  
Air Bubble Entrainment ◽  
Inflow Conditions

Air bubble entrainment at plunging jet takes place when the jet impact velocity exceeds a critical velocity function of the inflow conditions. This study investigates scale effects affecting air entrainment and bubble dispersion at vertical circular plunging jets. Three scale models were used and detailed air-water measurements were performed systematically for identical Froude numbers. The results highlight significant scale effects when We1 < 1E+3 or V1/ur < 10. Bubble chord times were also measured and presented in terms of pseudo-bubble chord length which was found to overestimate real bubble chords by 10 to 30%. The data show pseudo-bubble chord sizes ranging from less than 0.5 mm to more than 10 mm. The average pseudo-chord sizes were between 5 and 7 mm.

scholarly journals Air Entrainment in the Developing Flow Region of Plunging Jets—Part 1: Theoretical Development

1997 ◽  
Vol 119 (3) ◽  
pp. 597-602 ◽  
Author(s):  
P. D. Cummings ◽  
H. Chanson
Keyword(s):  
Flow Region ◽  
Air Entrainment ◽  
Theoretical Development ◽  
Liquid Jets ◽  
Two Dimensional ◽  
Air Bubble ◽  
Developing Flow ◽  
Jet Impact ◽  
Plunging Jets ◽  
Advective Diffusion

Air-water bubbly flows are encountered in many engineering applications. One type of air-water shear flows is the developing flow region of a plunging jet. The mechanisms of air entrainment by plunging liquid jets are discussed in the light of new experimental evidence. Then the air bubble diffusion is analyzed analytically in the near-flow field of both circular and two-dimensional plunging jets. The theoretical developments are compared with existing circular plunging jet data and new experiments performed with a two-dimensional vertical supported jet. The study highlights two mechanisms of air entrainment at the plunge point depending upon the jet impact velocity and results suggest that the dispersion of air bubbles within the shear layer is primarily an advective diffusion process.

scholarly journals An extension of Fuhrboter's studies for wave height: a theoretical study

1970 ◽  
Vol 34 (2) ◽  
pp. 115-122
Author(s):  
Azizur Rahman ◽  
MST Kamrunnaher ◽  
Ashabul Hoque
Keyword(s):  
Key Words ◽  
Wave Height ◽  
Theoretical Study ◽  
Air Entrainment ◽  
Air Bubbles ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
Air Bubble Entrainment ◽  
Spilling Breakers ◽  
Academy Of Sciences

This theoretical study extends Fuhrboter's work and includes the effects of air bubble entrainment. Result shows that there is a correlation between the sudden reductions of wave height and entrained of air bubbles into the water. Moreover, the study reveals that air entrainment occurs very short way in plunging breakers comparatively to spilling breakers. Key words: Fuhrboter's studies; Wave height; Theoretical study DOI: 10.3329/jbas.v34i2.6855Journal of Bangladesh Academy of Sciences, Vol. 34, No. 2, 115-122, 2010

Air Bubble Entrainment, Breakup, and Interplay in Vertical Plunging Jets

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Numa Bertola ◽  
Hang Wang ◽  
Hubert Chanson
Keyword(s):  
High Speed ◽  
Point Explosion ◽  
Air Bubble ◽  
Bubble Breakup ◽  
Jet Impact ◽  
Bubble Entrainment ◽  
Bubble Interaction ◽  
Onset Velocity ◽  
Air Cavities ◽  
Interaction Behaviors

The entrainment, breakup, and interplay of air bubbles were observed in a vertical, two-dimensional supported jet at low impact velocities. Ultra-high-speed movies were analyzed both qualitatively and quantitatively. The onset velocity of bubble entrainment was between 0.9 and 1.1 m/s. Most bubbles were entrained as detached bubbles from elongated air cavities at the impingement point. Explosion, stretching, and dejection mechanisms were observed for individual bubble breakup, and the bubble interaction behaviors encompassed bubble rebound, “kiss-and-go,” coalescence and breakup induced by approaching bubble(s). The effects of jet impact velocity on the bubble behaviors were investigated for impact velocities from 1.0 to 1.36 m/s, in the presence of a shear flow environment.

scholarly journals F113 Improvement of Hydrofoil Performance on Air Bubble Entrainment for Drag Reduction of Ships

2013 ◽  
Vol 2013.18 (0) ◽  
pp. 187-188
Author(s):  
Ichiro KUMAGAI ◽  
Haruki SAKAMAKI ◽  
Yuji TASAKA ◽  
Yoshihiko OISHI ◽  
Yuichi MURAI
Keyword(s):  
Drag Reduction ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
Air Bubble Entrainment
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