Bubble Oscillations of Large Amplitude,

Keller, Joseph B.; Miksis, Michael J.

doi:10.21236/ada095754

Cited by 197 publications

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“…It should be noted that, in (9), the effect of the viscosity-induced vortex fluid motion caused by radial oscillations of the bubble on the shape variation of this bubble is described by the fourth term (defined in terms of the function T i ), and the effect of the viscosity of the potential fluid motion is taken into account by the second and third terms. In the literature, additional assumptions are also used to simplify the description of the vortex motion of the fluid.…”

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

“…Accounting for fluid compressibility (neglecting bubble nonsphericity) only leads to a change in the equation for the bubble radius. In the present paper, fluid compressibility is taken into account in accordance with [9]. In this case, instead of the Rayleigh-Lamb equation (7), we have…”

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

“…It should be noted that, in fact, Eq. (12) takes into account only fluid compressibility away from the bubble [9]. Thus, the simplified formulation of the problem used in this paper includes Eqs.…”

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

“…This interval is divided into N equal intervals of length Δξ = 1/N . The integrals in (9) are calculated by the trapezoidal formula. The partial derivatives in Eq.…”

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

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Effect of vortex fluid motion on nonspherical oscillations of a gas bubble

Аганин

Ilgamov

Toporkov

2010

J Appl Mech Tech Phy

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This paper studies the effect of the vortex fluid motion produced by periodic radial oscillations of a weakly nonspherical gas bubble on the variation in the small initial deviation from the spherical shape of this bubble. It is shown that the most intense vortex motion of the fluid occurs in the boundary layer (near field ), and in the far field, the vortex fluid motion rapidly transforms to potential motion. The ranges of problem parameters in which vortex motion in the far field flow does not affect bubble oscillations and the ranges in which accounting for this motion is necessary for a qualitatively correct description of the oscillations are determined.Key words: periodic action, stability of spherical bubble shape, deviation, effect of vortex motion, vorticity.Introduction. Bubble dynamics research has been stimulated by the discovery of stable periodic singlebubble sonoluminescence, by which is meant the periodic emission of short light pulses by a small gas bubble which oscillates at the antinode of an ultrasonic standing pressure wave [1,2]. In addition, there has been increased interest in the variation in the deviation of the bubble shape from a sphere during periodic oscillations. Until recently, the ranges of stable oscillations have been primarily determined [3,4].In this paper, we study the effect of the vortex fluid motion caused by periodic radial oscillations of a weakly nonspherical bubble on the variation in the small initial deviation of the bubble shape from a sphere. Emphasis is placed on the effect of vortex motion in the far (relative to the bubble) flow field. As is known, if a body placed in a weakly viscous fluid performs high-frequency oscillations whose amplitude is small compared to the body size, the most intense vortex motion of the fluid occurs in the boundary layer (near field) of thickness δ c ∼ 2ν/ω c , where ω c is the oscillation frequency and ν is the kinematic viscosity [5]. At distances larger than δ c (in the far field), the fluid motion rapidly becomes potential; therefore, in many cases, the vortex motion in the far field can be neglected. This assumption is made in most of the well-known approximate methods of taking into account the effect of viscosity on the dynamics of gas bubbles (see, for example, [6]). If the frequency and amplitude of nonspherical oscillations vary widely, the intensity ratio of the vortex motion in the near and far (in the region r > R + δ c ) fields can vary. In the present work, we use a model in which the evolution of the deviation of the bubble shape from sphericity is described by an equation [7] which takes into account vortex fluid motion in both the near and far field.It is shown that during stable radial oscillations, the variation in the deviation from period to period can be not only exponential (as is the case under the effect of the near vorticity field) but much slower (power-law) due to the effect of vortex fluid motion in the far field. In addition, the deviation value can alternatively decrease and increase from period to per...

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Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

“…This interval is divided into N equal intervals of length Δξ = 1/N . The integrals in (9) are calculated by the trapezoidal formula. The partial derivatives in Eq.…”

Section: Formulation Of the Problem Using Continuity And Motion Equatmentioning

confidence: 99%

See 2 more Smart Citations

Effect of vortex fluid motion on nonspherical oscillations of a gas bubble

Аганин

Ilgamov

Toporkov

2010

J Appl Mech Tech Phy

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“…The model uses the Rayleigh-Plesset equation [16], modified to include the compressibility effects and mass transfer processes [12], to approximate the liquid continuity and momentum equations. This equation has been widely used by other authors to describe the liquid behavior [15,18,23,27].…”

Section: Case Studymentioning

confidence: 99%

Parametric Analysis for a Single Collapsing Bubble

Fuster

Hauke

Dopazo

2008

Flow Turbulence Combust

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This work presents a sensitivity analysis for cavitation processes, studying in detail the effect of various model parameters on the bubble collapse. A complete model (Hauke et al. Phys Rev E 75:1-14, 2007) is used to obtain how different parameters influence the collapse in SBSL experiments, providing some clues on how to enhance the bubble implosion in real systems. The initial bubble radius, the frequency and the amplitude of the pressure wave are the most important parameters determining under which conditions cavitation occurs. The range of bubble sizes inducing strong implosions for different frequencies is computed; the initial radius is the most important parameter characterized the intensity of the cavitation processes. However, other parameters like the gas and liquid conductivity or the liquid viscosity can have an important effect under certain conditions. It is shown that mass transfer processes play an important role in order to correctly predict the trends related with the effect of the liquid temperature, which translates into the bubble dynamics. Moreover, under some particular circumstances, evaporation can be encountered during the bubble collapse; this can be profitably exploited in order to feed reactants when the most extreme conditions inside the bubbles are reached. Thus, this paper aims at providing a global assessment of the effect of the different parameters on the entire cycle of a single cavitating spherical bubble immersed in an ultrasonic field.

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Integrated approach to optimization of an ultrasonic processor

Moholkar

Warmoeskerken

2003

AIChE Journal

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In an ultrasonic processor, the input electrical energy undergoes many transformations before getting con®erted into the ca®itation energy, which is dissipated in the medium to bring out the physicalrchemical change. An in®estigation of the influence of free and dissol®ed gas content of the system on the efficiency of this energy transformation chain is attempted. The results of the experiments re®eal that the ca®itation intensity produced in the medium ®aries significantly with the gas content of the system. A unified physical model, which combines basic theories of acoustics and bubble dynamics, has been used to explain the experimental results. An attempt has been made to establish the mechanism of the steps in the energy transformation chain, the in®ol®ed physical parameters, and interrelations between them. It has been found that the influence of free and dissol®ed gas content of the medium on the o®erall energy transformation occurs through a complex inter-dependence of se®eral parameters. Thus, simultaneous optimization of indi®idual steps in the energy transformation chain, with an integrated approach, is necessary for the optimization of an ultrasonic processor. The present study puts forth a simple methodology, with the gas content of the system as manipulation parameter, for this purpose.

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Bubble Oscillations of Large Amplitude,

Cited by 197 publications

References 0 publications

Effect of vortex fluid motion on nonspherical oscillations of a gas bubble

Effect of vortex fluid motion on nonspherical oscillations of a gas bubble

Parametric Analysis for a Single Collapsing Bubble

Integrated approach to optimization of an ultrasonic processor

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