Regimes during liquid drop impact on a liquid pool

2015 ◽  
Vol 768 ◽  
pp. 492-523 ◽  
Author(s):  
Bahni Ray ◽  
Gautam Biswas ◽  
Ashutosh Sharma

Water drops falling on a deep pool can either coalesce to form a vortex ring or splash, depending on the impact conditions. The transition between coalescence and splashing proceeds via a number of intermediate steps, such as thick and thin jet formation and gas-bubble entrapment. We perform simulations to determine the conditions under which bubble entrapment and jet formation occur. A regime map is established for Weber numbers ranging from 50 to 300 and Froude numbers from 25 to 600. Vortex ring formation is seen for all of the regimes; it is greater for the coalescence regime and less in the case of the thin jet regime.

Author(s):  
I V Khramtsov ◽  
VV Palchikovskiy ◽  
A A Siner ◽  
Yu V Bersenev

2015 ◽  
Vol 219 (3) ◽  
pp. 392-403 ◽  
Author(s):  
Ian K. Bartol ◽  
Paul S. Krueger ◽  
Rachel A. Jastrebsky ◽  
Sheila Williams ◽  
Joseph T. Thompson

1992 ◽  
Vol 5 (3) ◽  
pp. 274-276 ◽  
Author(s):  
R.A. Mikael Kortz ◽  
Ben J. Delemarre ◽  
Hans Bot ◽  
Cees A. Visser

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Moshe Rosenfeld ◽  
Kakani Katija ◽  
John O. Dabiri

Vortex rings are one of the fundamental flow structures in nature. In this paper, the generation of circulation and vortex rings by a vortex generator with a static converging conic nozzle exit is studied numerically. Conic nozzles can manipulate circulation and other flow invariants by accelerating the flow, increasing the Reynolds number, and by establishing a two-dimensional flow at the exit. The increase in the circulation efflux is accompanied by an increase in the vortex circulation. A novel normalization method is suggested to differentiate between two contributions to the circulation generation: a one-dimensional slug-type flow contribution and an inherently two-dimensional flow contribution. The one-dimensional contribution to the circulation increases with the square of the centerline exit velocity, while the two-dimensional contribution increases linearly with the decrease in the exit diameter. The two-dimensional flow contribution to the circulation production is not limited to the impulsive initiation of the flow only (as in straight tube vortex generators), but it persists during the entire ejection. The two-dimensional contribution can reach as much as 44% of the total circulation (in the case of an orifice). The present study offers evidences on the importance of the vortex generator geometry, and in particular, the exit configuration on the emerging flow, circulation generation, and vortex ring formation. It is shown that both total and vortex ring circulations can be controlled to some extent by the shape of the exit nozzle.


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