The Rayleigh-like collapse of a conical bubble

Leighton, Timothy G.; Cox, Ben; Phelps, A.D.

doi:10.1121/1.428296

Cited by 47 publications

(55 citation statements)

References 17 publications

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“…The inertia of a spherical bubble oscillating in an infinite body of liquid is finite and given by m 0 = 4πR 0 3 ρ (Leighton et al, 1998), where ρ is the liquid density and R 0 is the bubble equilibrium radius. In such a situation, the fluid velocity falls off as a square law with distance from the bubble.…”

Section: Discussion and Summarymentioning

confidence: 99%

“…In general, one should expect that the larger the bubble size is with respect to the tube diameter, the greater the degree to which the inertia will depart from the free value m 0 . As the bubble grows to fill the tube cross-section, its inertia will increase from a value close to m 0 to a value approaching m in a continuous rate, although not linearly (Leighton et al 1998;. Leighton and associates modeled a situation in which the fluid velocity falls off as an inverse square law close to the bubble, i.e.…”

Section: Discussion and Summarymentioning

confidence: 99%

“…However, it can be expected that the larger the bubble size with respect to the tube diameter, the greater the degree to which the bubble inertia departs from its free value. Leighton et al (1998Leighton et al ( , 2000 have modelled the Rayleigh-like collapse of a conical bubble. In such a situation, when the bubble is small the fluid flow has a spherical symmetry and the bubble inertia is close to the free inertia, but tends to the one-dimensional inertia when the bubble is large.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cavitation Threshold of Microbubbles in Gel Tunnels by Focused Ultrasound

Sassaroli

Hynynen

2007

Ultrasound in Medicine & Biology

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The investigation of inertial cavitation in micro-tunnels has significant implications for the development of therapeutic applications of ultrasound such as ultrasound-mediated drug and gene delivery. The threshold for inertial cavitation was investigated using a passive cavitation detector with a center frequency of 1 MHz. Micro-tunnels of various diameters (90 to 800 μm) embedded in gel were fabricated and injected with a solution of Optison™ contrast agent of concentrations 1.2% and 0.2% diluted in water. An ultrasound pulse of duration 500 ms and center frequency 1.736 MHz was used to insonate the microbubbles. The acoustic pressure was increased at one second intervals until broadband noise emission was detected. The pressure threshold at which broadband noise emission was observed was found to be dependent on the diameter of the micro-tunnels, with an average increase of 1.2 to 1.5 between the smallest and the largest tunnels, depending on the microbubble concentration. The evaluation of inertial cavitation in gel tunnels rather than tubes provides a novel opportunity to investigate microbubble collapse in a situation that simulates in vivo blood vessels better than tubes with solid walls do.

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Section: Discussion and Summarymentioning

confidence: 99%

Section: Discussion and Summarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cavitation Threshold of Microbubbles in Gel Tunnels by Focused Ultrasound

Sassaroli

Hynynen

2007

Ultrasound in Medicine & Biology

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“…Since PWFF conditions never exist in practice in bubbly liquids, strictly speaking no such inversion for BSD from travelling wave attenuations and sound speed has ever done this, although clearly under some circumstances the approximation is sufficiently good (Wilson et al 2005). Note however that the method here does not account for the effects on the bubble dynamics themselves of the wall of a tank (Strasberg 1953;Leighton et al 2002) or pipe (Leighton et al 1995(Leighton et al , 1997(Leighton et al , 1998bLeighton 2011), or the departure from linearity or steady-state conditions (Clarke & Leighton 2000), all of which could be included given sufficient computational resources (Leighton et al 2004). Figure 4a plots Y j , the ratio of the imaginary part to the real part of the complex wavenumber as defined in equation (2.4), for infinite volumes of homogeneous bubbly liquid.…”

Section: (A) Validation Tests Using Simulated Acoustic Data Based On mentioning

confidence: 99%

The use of acoustic inversion to estimate the bubble size distribution in pipelines

2012

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The most popular technique for estimating the gas bubble size distribution (BSD) in liquids is through the inversion of measured attenuation and/or sound speed of a travelling wave. The model inherent in such inversions never exactly matches the conditions of the measurement, and the size of the resulting error (which could well be small in quasi-free field conditions) cannot be quantified if only a free field code exists. Users may be unaware of errors because, with sufficient regularization, such inversions can always be made to produce an answer, the accuracy of which is unknown unless independent (e.g. optical) measurements are made. This study was commissioned to assess the size of this error for the mercury-filled steel pipelines of the target test facility (TTF) of the spallation neutron source at Oak Ridge National Laboratory, TN, USA. Large errors in estimating the BSD (greater than 1000% overcounts/undercounts) are predicted. A new inversion technique appropriate for pipelines such as TTF gives good BSD estimations if the frequency range is sufficiently broad. However, it also shows that implementation of the planned reduction in frequency bandwidth for the TTF bubble sensor would make even this inversion insufficient to obtain an accurate BSD in TTF.

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“…It also leads to the creation of bubble fragments (figure 9e) that may coalesce with the main cavity or act as nuclei for further cavitation events. The most likely scenario is that these fragments expand and undergo some coalescence during the prolonged tensile tail of the lithotripter pulse (Leighton, Ho & Flaxman 1997;Leighton et al 1998;Leighton, Cox & Phelps 2000). The peak overpressure exceeds 1 GPa.…”

Section: Bubble Dynamicsmentioning

confidence: 99%

The collapse of single bubbles and approximation of the far-field acoustic emissions for cavitation induced by shock wave lithotripsy

et al. 2011

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Recent clinical trials have shown the efficacy of a passive acoustic device used during shock wave lithotripsy (SWL) treatment. The device uses the far-field acoustic emissions resulting from the interaction of the therapeutic shock waves with the tissue and kidney stone to diagnose the effectiveness of each shock in contributing to stone fragmentation. This paper details simulations that supported the development of that device by extending computational fluid dynamics (CFD) simulations of the flow and near-field pressures associated with shock-induced bubble collapse to allow estimation of those far-field acoustic emissions. This is a required stage in the development of the device, because current computational resources are not sufficient to simulate the far-field emissions to ranges of O(10 cm) using CFD. Similarly, they are insufficient to cover the duration of the entire cavitation event, and here simulate only the first part of the interaction of the bubble with the lithotripter shock wave in order to demonstrate the methods by which the far-field acoustic emissions resulting from the interaction can be estimated. A free-Lagrange method (FLM) is used to simulate the collapse of initially stable air bubbles in water as a result of their interaction with a planar lithotripter shock. To estimate the far-field acoustic emissions from the interaction, this paper developed two numerical codes using the Kirchhoff and Ffowcs William-Hawkings (FW-H) formulations. When coupled to the FLM code, they can be used to estimate the far-field acoustic emissions of cavitation events. The limitation of the technique is that it assumes that no significant nonlinear acoustic propagation occurs outside the control surface. Methods are outlined for ameliorating this problem if, as here, computational resources cannot compute the flow field to sufficient distance, although for the clinical situation discussed, this limitation is tempered by the effect of tissue absorption, which here is incorporated through the standard derating procedure. This approach allowed identification of the sources of, and explanation of trends seen in, the characteristics of the far-field emissions observed in clinic, to an extent that was sufficient for the development of this clinical device.

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The Rayleigh-like collapse of a conical bubble

Cited by 47 publications

References 17 publications

Cavitation Threshold of Microbubbles in Gel Tunnels by Focused Ultrasound

Cavitation Threshold of Microbubbles in Gel Tunnels by Focused Ultrasound

The use of acoustic inversion to estimate the bubble size distribution in pipelines

The collapse of single bubbles and approximation of the far-field acoustic emissions for cavitation induced by shock wave lithotripsy

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