Experimental and Theoretical Bubble Dynamics

Lauterborn, Werner; Kurz, Thomas; Mettin, Robert; Ohl, Claus‐Dieter

doi:10.1002/9780470141694.ch5

Cited by 116 publications

(84 citation statements)

References 71 publications

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“…Several proposed mechanisms of the effect of ultrasound on crystallisation have been published. These include the formation of local hot spots which arise from the large energy release on the collapse of cavitation bubbles creating highly localised regions of extremely high temperature and pressure [50,51], or due to rapid cooling which follows; shockwaves released from cavitation bubbles [52,53], promoting mass transfer and collisions between crystals and adjacent surfaces [54]. These effects of ultrasound on crystallisation have been demonstrated on pharmaceuticals and commodity chemicals including; lactose [35,39,42,55], alpha-dextrose monohydrate [20], glycine [48], p-aminobenzoic acid [47], adipic acid [28], benzoic acid [31], acetylsalicylic acid [27], protein [19] various food products [30,56,57] and in the crystallisation of inorganic materials such as potassium sulphate [26], potassium dihydrogen phosphate [32] and calcite [34].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Ultrasound on the Crystallisation of Paracetamol in the Presence of Structurally Similar Impurities

et al. 2017

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Sono-crystallisation has been used to enhance crystalline product quality particularly in terms of purity, particle size and size distribution. In this work, the effect of impurities and ultrasound on crystallisation processes (nucleation temperature, yield) and crystal properties (crystal size distribution determined by Focused Beam Reflectance Measurement (FBRM), crystal habit, filtration rate and impurity content in the crystal product by Liquid Chromatography-Mass Spectroscopy (LC-MS)) were investigated in bulk suspension crystallisation experiments with and without the use of ultrasound. The results demonstrate that ultrasonic intervention has a significant effect on both crystallisation and product crystal properties. It increases the nucleation rate resulting in smaller particles and a narrower Particle Size Distribution (PSD), the yield has been shown to be increase as has the product purity. The effect of ultrasound is to reduce the level acetanilide impurity incorporated during growth from a 2 mol% solution of the selected impurity from 0.85 mol% to 0.35 mol% and likewise ultrasound reduces the uptake of metacetamol from 1.88 mol% to 1.52 mol%.

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Section: Introductionmentioning

confidence: 99%

The Effect of Ultrasound on the Crystallisation of Paracetamol in the Presence of Structurally Similar Impurities

et al. 2017

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“…Bubble pairs flattened on the portion of their interfaces facing each other when they get close together and just before coalescence have been observed experimentally (e.g. Lauterborn et al 1999). Calculating the average distance between the bubble centres within each oscillation period and fitting these data to a quadratic polynomial in time, one obtains…”

Section: Nonlinear Dynamics Of Equal Bubblesmentioning

confidence: 99%

Viscous effects on the oscillations of two equal and deformable bubbles under a step change in pressure

2011

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According to linear theory and assuming the liquids to be inviscid and the bubbles to remain spherical, bubbles set in oscillation attract or repel each other with a force that is proportional to the product of their amplitude of volume pulsations and inversely proportional to the square of their distance apart. This force is attractive, if the forcing frequency lies outside the range of eigenfrequencies for volume oscillation of the two bubbles. Here we study the nonlinear interaction of two deformable bubbles set in oscillation in water by a step change in the ambient pressure, by solving the Navier–Stokes equations numerically. As in typical experiments, the bubble radii are in the range 1–1000 μm. We find that the smaller bubbles (~5 μm) deform only slightly, especially when they are close to each other initially. Increasing the bubble size decreases the capillary force and increases bubble acceleration towards each other, leading to oblate or spherical cap or even globally deformed shapes. These deformations may develop primarily in the rear side of the bubbles because of a combination of their translation and harmonic or subharmonic resonance between the breathing mode and the surface harmonics. Bubble deformation is also promoted when they are further apart or when the disturbance amplitude decreases. The attractive force depends on the Ohnesorge number and the ambient pressure to capillary forces ratio, linearly on the radius of each bubble and inversely on the square of their separation. Additional damping either because of liquid compressibility or heat transfer in the bubble is also examined.

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“…However, spherical-bubble collapse requires isotropic bubble surroundings and inherent stability conditions to be fulfilled with respect to spherical shape (parametric and Rayleigh-Taylor instability) (Plesset 1954;Strube 1971;Hilgenfeldt, Lohse & Brenner 1996;Ohl, Lindau & Lauterborn 1998;Lauterborn et al 1999;Ohl et al 1999;Lin, Storey & Szeri 2002;Koch et al 2011). The interaction of a bubble with its environment generically establishes an asymmetry that, for strong interaction, leads to jet formation, whereby the bubble pierces itself with a high-speed liquid jet.…”

mentioning

confidence: 99%

“…Dynamics of laser-induced bubble pairs 707 et al 1992; Putterman & Weninger 2000;Akhatov et al 2001;Brenner, Hilgenfeldt & Lohse 2002;Suslick & Flannigan 2008;Lauterborn & Kurz 2010;Schanz et al 2012). However, spherical-bubble collapse requires isotropic bubble surroundings and inherent stability conditions to be fulfilled with respect to spherical shape (parametric and Rayleigh-Taylor instability) (Plesset 1954;Strube 1971;Hilgenfeldt, Lohse & Brenner 1996;Ohl, Lindau & Lauterborn 1998;Lauterborn et al 1999;Ohl et al 1999;Lin, Storey & Szeri 2002;Koch et al 2011).…”

mentioning

confidence: 99%

Dynamics of laser-induced bubble pairs

et al. 2015

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The interaction of two laser-induced bubbles in bulk water is investigated. The strength and direction of the emerging liquid jets can be controlled by adjusting the relative bubble positions, the time difference between bubble generation, and the laser pulse energies determining the bubble sizes. Experimental and numerical studies are performed for millimetre-sized bubble pairs. Taking bubbles of equal energy, a maximum jet velocity is found for close anti-phase bubbles, i.e. when the second bubble is produced at the maximum volume of the first one and the bubble walls are almost touching and not merging. Under these conditions, one bubble produces a fast jet with a peak velocity of about 150 m s −1 that reaches a distance into the surrounding liquid of at least three times the maximum bubble radius. Collapse of the other bubble results in a slow jet of large mass that rapidly converts into a ring vortex. Correspondingly, the interaction with adjacent structures is dominated either by localized jet impact or by shear stresses extending over a larger area. Furthermore, interactions between micrometre-sized bubble pairs are investigated numerically to understand and predict how the effects of the physical parameters on bubble dynamics would change when the bubbles become smaller. The results are discussed with respect to micropumping and opto-injection.

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Experimental and Theoretical Bubble Dynamics

Cited by 116 publications

References 71 publications

The Effect of Ultrasound on the Crystallisation of Paracetamol in the Presence of Structurally Similar Impurities

The Effect of Ultrasound on the Crystallisation of Paracetamol in the Presence of Structurally Similar Impurities

Viscous effects on the oscillations of two equal and deformable bubbles under a step change in pressure

Dynamics of laser-induced bubble pairs

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