scholarly journals Vortex-ring-induced large bubble entrainment during drop impact

2016 ◽  
Vol 93 (3) ◽  
Author(s):  
Marie-Jean Thoraval ◽  
Yangfan Li ◽  
Sigurdur T. Thoroddsen
Keyword(s):  
Vortex Ring ◽  
Drop Impact ◽  
Large Bubble ◽  
Bubble Entrainment

The regime of large bubble entrapment during a single drop impact on a liquid pool

2017 ◽  
Vol 29 (9) ◽  
pp. 092101 ◽  
Author(s):  
Hiranya Deka ◽  
Bahni Ray ◽  
Gautam Biswas ◽  
Amaresh Dalal ◽  
Pei-Hsun Tsai ◽  
...  
Keyword(s):  
Drop Impact ◽  
Liquid Pool ◽  
Large Bubble ◽  
Single Drop

Irregular Bubble Entrainment Following Drop Impact on a Free Surface

2003 ◽  
Author(s):  
Yukio Tomita ◽  
Toshiyasu Kasai ◽  
Shinya Miura
Keyword(s):  
Free Surface ◽  
Impact Velocity ◽  
Water Surface ◽  
Drop Impact ◽  
Drop Diameter ◽  
Air Bubbles ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
Irregular Case ◽  
The Impact

An air bubble is entrained by the impact of a drop on a water surface. Consequently sound is emitted. There are two categories of the bubble entrainment depending on the drop diameter dD and impact velocity Vimp. One is the regular entrainment where air bubbles are always pinched off, another is the irregular case where bubbles are trapped irregularly. In this paper we explore the mechanism of the irregular bubble entrainment and induced bubble sound.

Crown behavior and bubble entrainment during a drop impact on a liquid film

2013 ◽  
Vol 28 (2) ◽  
pp. 159-170 ◽  
Author(s):  
Gangtao Liang ◽  
Yali Guo ◽  
Shengqiang Shen ◽  
Yong Yang
Keyword(s):  
Liquid Film ◽  
Drop Impact ◽  
Bubble Entrainment

Surface breakup and air bubble formation by drop impact in the irregular entrainment region

2007 ◽  
Vol 588 ◽  
pp. 131-152 ◽  
Author(s):  
Y. TOMITA ◽  
T. SAITO ◽  
S. GANBARA
Keyword(s):  
Froude Number ◽  
Water Column ◽  
Water Surface ◽  
Bubble Formation ◽  
Drop Impact ◽  
Air Bubbles ◽  
Bubble Generation ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
The Impact

Drop impact on a water surface can be followed by underwater sounds originating not at the drop impact but when the entrained bubbles oscillate. Although the sound mechanism in the regular bubble entrainment region is well-known, there is less knowledge on the impact phenomena in the irregular bubble entrainment region where various situations can exist, such as many types of bubble formation or even no bubble generation under some conditions. In the present study, the aim is to clarify the dynamics of the water surface after the impact of a primary drop, mainly with diameter 5.2, 5.7 and 6.2mm, each of which is accompanied by a single satellite drop. Special attention was paid to the breakup behaviour of the water surface for Froude number Fr < 300. It was found that three underwater sounds were generated for a single drop impact, besides the sound due to impact itself. The first two were audible to the human ear, but the third one was almost inaudible. The first underwater sound resulted from the oscillation of a single air bubble formed as a result of the satellite drop impact on the bottom of the contracting cavity, and the second sound was due to the oscillation of air bubbles generated during the collapse of the water column. The formation of these air bubbles strongly depends on the Froude number, Weber number (or Bond number) and the aspect ratio of the drop at impact, although involving probability characteristics. Furthermore it is suggested that an air bubble entrapped in a water column plays an important role in increasing the probability of contact between the column surface and the curved free surface. A Japanese Suikinkutsu was introduced as an application of drop-impact-induced sounds. Using an open-type Suikinkutsu an additional experiment was carried out with larger drops with average diameters of 6.2, 7.2 and 7.8, mm.

Single drop impact onto liquid films: neck distortion, jetting, tiny bubble entrainment, and crown formation

1999 ◽  
Vol 385 ◽  
pp. 229-254 ◽  
Author(s):  
DANIEL A. WEISS ◽  
ALEXANDER L. YARIN
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Characteristic Time ◽  
Liquid Films ◽  
Drop Impact ◽  
Boundary Integral ◽  
Liquid Volume ◽  
Single Drop ◽  
Bubble Entrainment ◽  
The Impact

Single drop impact onto liquid films is simulated numerically. Surface tension and gravity are taken into account, whereas viscosity and compressibility are neglected. This permits recourse to a boundary-integral method, based on an integral equation for a scalar velocity potential. Calculations are performed for normal impacts resulting in axisymmetric flows.For times that are small compared to the characteristic time of impact 2R/w0 (R being the drop radius, w0 its initial velocity towards the liquid film), it is found that a disk-like jet forms at the neck between the drop and the pre-existing liquid film, if the impact Weber number is high enough. This jet can pinch off a torus-shaped liquid volume at its tip or reconnect with the pre-existing liquid film, thus entraining a torus- shaped bubble. In reality, both the torus-shaped bubble and liquid torus will decay according to Rayleigh's capillary instability, thus breaking the cylindrical symmetry. This mechanism of bubble entrainment differs from those described in literature.For times that are comparable to or larger than the characteristic time of impact, capillary waves on the film, or the well-known crowns, are obtained again according to whether the impact Weber number is low or high enough.

scholarly journals A bubble entrainment by a small refrigerant drop impact on water surface

2011 ◽  
Vol 31 (7) ◽  
pp. 27-32 ◽  
Author(s):  
Hisanobu Kawashima ◽  
Ryota Shibasaki ◽  
Tsuneaki Ishima
Keyword(s):  
Water Surface ◽  
Drop Impact ◽  
Bubble Entrainment

scholarly journals Maximal Air Bubble Entrainment at Liquid-Drop Impact

2012 ◽  
Vol 109 (26) ◽  
Author(s):  
Wilco Bouwhuis ◽  
Roeland C. A. van der Veen ◽  
Tuan Tran ◽  
Diederik L. Keij ◽  
Koen G. Winkels ◽  
...  
Keyword(s):  
Liquid Drop ◽  
Drop Impact ◽  
Air Bubble ◽  
Bubble Entrainment ◽  
Air Bubble Entrainment

Modeling and Simulation of Multiple Bubble Entrainment and Interactions With a Traveling Vortex Ring

2012 ◽  
Author(s):  
Andrew J. Cihonski ◽  
Justin R. Finn ◽  
Sourabh V. Apte
Keyword(s):  
Vortex Ring ◽  
Vortex Core ◽  
Three Dimensional ◽  
Mixture Theory ◽  
Hydrodynamic Pressure ◽  
Coupling Model ◽  
Fluid Displacement ◽  
Lagrange Formulation ◽  
Bubble Entrainment ◽  
Coupling Approach

Bubble interactions with vortical structures are important to better understand the mechanisms of bubble induced boundary layer drag reduction and chemical mixing. Traditionally, many studies of disperse bubble or particle-laden flows have utilized an Euler-Lagrange two-way coupling approach, wherein the dispersed phase is assumed subgrid and its dynamics is modeled. In this work, results on full three-dimensional simulation of traveling vortex ring together with a few microbubbles are presented utilizing a volumetric coupling approach, wherein the displaced mass due to the presence of the bubbles is accounted for by using mixture theory based conservation laws in an Euler-Lagrange formulation. It is shown that the volumetric coupling approach is necessary to reproduce the experimental observations of Sridhar & Katz, JFM (1999). Experimental work by S&K on bubble entrainment into a traveling vortex ring has shown that the settling location of the bubble relative to the vortex core can be well predicted based on the ratio of the buoyancy force to the hydrodynamic pressure gradient. Additionally, the experimental results find that even at low volume fractions, bubble injection can significantly affect the structure of the vortex core. The two-way coupling model, wherein the fluid displacement due to bubble motion is neglected, of bubble-laden flows is unable to capture these effects on the vortical structure.

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