Three-Dimensional Study of the Nonrectilinear Trajectory of Air Bubbles Rising in Water

Mercier, J.; Lyrio, Aurélia Leal Lima; Forslund, R.

doi:10.1115/1.3423065

Cited by 19 publications

(4 citation statements)

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“…Path oscillations have been investigated by numerous experimenters including Haberman & Morton (1954), Saffman (1956), Hartunians & Sears (1957), Aybers & Tapucu (1969a, b), Mercier, Lyrio & Forslund (1973), Tsuge & Hibino (1977), Duineveld (1994Duineveld ( , 1995, Lunde & Perkins (1997, 1998, and Ford & Loth (1998). Different regimes exist depending on the equivalent bubble diameter.…”

Section: Comparison With Other Studies and Discussionmentioning

confidence: 99%

On the rise of an ellipsoidal bubble in water: oscillatory paths and liquid-induced velocity

2001

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This work is an experimental study of the rise of an air bubble in still water. For the bubble diameter considered, path oscillations develop in the absence of shape oscillations and the effect of surfactants is shown to be negligible. Both the three-dimensional motion of the bubble and the velocity induced in the liquid are investigated. After the initial acceleration stage, the bubble shape remains constant and similar to an oblate ellipsoid with its symmetry axis parallel to the bubble-centre velocity, and with constant velocity magnitude. The bubble motion combines path oscillations with slow trajectory displacements. (These displacements, which consist of horizontal drift and rotation about a vertical axis, are shown to have no influence on the oscillations). The bubble dynamics involve two unstable modes which have the same frequency and are π/2 out of phase. The primary mode develops first, leading to a plane zigzag trajectory. The secondary mode then grows, causing the trajectory to progressively change into a circular helix. Liquid-velocity measurements are taken up to 150 radii behind the bubble. The nature of the liquid flow field is analysed from systematic comparisons with potential theory and direct numerical simulations. The flow is potential in front of the bubble and a long wake develops behind. The wake structure is controlled by two mechanisms: the development of a quasi-steady wake that spreads around the non-rectilinear bubble trajectory; and the wake instability that generates unsteady vortices at the bubble rear. The velocities induced by the wake vortices are small compared to the bubble velocity and, except in the near wake, the flow is controlled by the quasi-steady wake.

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Section: Comparison With Other Studies and Discussionmentioning

confidence: 99%

On the rise of an ellipsoidal bubble in water: oscillatory paths and liquid-induced velocity

2001

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“…The literature on the subject of zigzagging and spiralling gas bubbles is extensive (e.g. Saffman, 1956;Lunde and Perkins, 1995;Aybers and Tapucu, 1969;Mercier et al, 1973;Ellingsen, 1998), and the experimental data are inconsistent on various aspects of the bubble motion. One of the reasons may be the continuous bubble release used in some of the experiments, because of which the path of a bubble is influenced by the preceding bubbles, another is the far from smooth release of the bubbles from the top of a needle, causing large deformations and unsteady behaviour of the bubble surface just after the release.…”

Section: Introductionmentioning

confidence: 99%

Notes on the path and wake of a gas bubble rising in pure water

Vries

Biesheuvel

Wijngaarden

2002

International Journal of Multiphase Flow

185

107

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“…Aybers and Tapucu [1,2]used photographic techniques to measure bubble speed, drag coefficients, size, shape, and path. Mercier, Lyrio, and Forslund [17] used a stroboscope and several cameras to measure short sections of bubble trajectories. More recently, Wu and Gharib used a high speed video three-dimensional imaging system to measure paths and bubble shape.…”

Section: Introductionmentioning

confidence: 99%

Force measurements on rising bubbles

Shew¹,

Poncet²,

Pinton³

2006

J. Fluid Mech.

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The dynamics of millimeter sized air bubbles rising through still water are investigated using precise ultrasound velocity measurements combined with high speed video. From measurements of speed and three dimensional trajectories we deduce the forces on the bubble which give rise to planar zigzag and spiraling motion. I. BACKGROUNDAn understanding of bubble-fluid interactions is important in a broad range of natural, engineering, and medical settings. Air-sea gas transfer, bubble column reactors, oil/natural gas transport, boiling heat transfer, ship hydrodynamics, ink-jet printing and medical ultrasound imaging are just a few examples where the dynamics of bubbles play a role (e.g [6,16,26]).We narrow our focus to a single air bubble rising through still water. The buoyant force which drives the bubble's rise does work resulting in an increase in kinetic energy of the surrounding fluid. This induced flow, in turn, gives rise to hydrodynamic forces on the bubble and hence changes in the bubble trajectory. The measurement of these forces is the aim of the experimental work presented here Our study includes a range of bubble sizes between 0.84 and 1.2 mm in radius. At the small end of this range the bubble's path is rectilinear. As the bubble size is increased, one observes a transition to a planar zigzag path [8,23]. A second instability, often preceded by the zigzag, results in a spiraling path [5,8,15,23]. For even larger bubbles, a third type of oscillating path occurs, which has similarities to the zigzag, sometimes called "rocking". We do not address this state and emphasize that it is different than the zigzag mentioned above. Unlike the zigzag state that we study, the rocking bubble undergoes dramatic shape oscillations and the frequency of path oscillation is several times higher than the zigzag or spiral [5,15]. Our approach is to use well resolved measurements of three-dimensional bubble trajectories to calculate the hydrodynamic forces on the bubbles. Other recent studies have investigated path instabilities with special attention paid to the role of the bubble's wake. Lunde and Perkins [15] used dye to observe the wake of ascending bubbles and solid particles. Brücker [5] used particle image velocimetry to study the wake of large spiraling and rocking bubbles. Mougin and Magnaudet [22,23] These studies have revealed a wake consisting of two long, thin, parallel vortices aligned with the bubble's path. One vortex rotates clockwise and the other counter-clockwise. For a spiraling bubble the wake vortices are continuously generated, while they are interrupted twice per period of path oscillation for the zigzag. Mougin and Magnaudet [22,23] observed a nearly identical wake structure in their numerical simulations (see also [24]). It is believed that the wake vortices play a critical role in generating hydrodynamic forces on the bubble.In the next section we describe the experimental apparatus and measurement techniques, as well a typical bubble trajectory. In section III, we present a method for extracti...

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Three-Dimensional Study of the Nonrectilinear Trajectory of Air Bubbles Rising in Water

Cited by 19 publications

References 0 publications

On the rise of an ellipsoidal bubble in water: oscillatory paths and liquid-induced velocity

On the rise of an ellipsoidal bubble in water: oscillatory paths and liquid-induced velocity

Notes on the path and wake of a gas bubble rising in pure water

Force measurements on rising bubbles

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