Effect of nuclei concentration on cavitation cluster dynamics

Abstract

Cavitation cluster dynamics after the passage of a single pressure wave is studied for different concentrations of artificial cavitation nuclei (30 to 3 · 10 5 nuclei/ml). With increasing concentration of cavitation nuclei the life time of the cavitation cluster is prolonged. Additionally, we find that the spatial extent of the cluster decreases with higher nuclei concentration. The experimental data for concentrations less than 400 nuclei/ml are compared to simulations with a Rayleigh-Plesset type equation, taking into account bubble-bubble interaction. For higher concentrations (more than 1000 nuclei/ml) the observed radial cluster dynamics is compared with an calculations from axisymmetric cavitycollapse model.2

Modelling bubble clusters in compressible liquids

“…The presence of bubble nuclei induces a positive wave whose amplitude increases with the concentration of bubbles. The structure of this wave promoted by the presence of bubbles is also similar to that experimentally observed by Arora et al (2007).…”

“…The increase of the bubble nuclei concentration induces significant changes in the structure of the tensile phase. The structure of the waves induced by the presence of the bubble nuclei is similar to that observed by Arora et al (2007): the strength and frequency of the secondary waves increases with the concentration of bubble nuclei. FIGURE 9.…”

“…These values fit relatively well the shape of the tensile part tested in Arora et al (2007), although the amplitude is about 3 times less intense. The differences in the shock wave arriving first are more pronounced but, as the void fraction is low, we do not expect bubbles to significantly disturb the shape of the wave (this fact has been experimentally verified by Arora et al 2007). The ellipsoid is generated by randomly distributing bubbles whose equilibrium radii obey a log-normal distribution with R = 5 µm and σ = 0.7.…”

“…The positive wave arrives first and the negative part of the wave gives rise to cavitation and bubble implosion. Trying to mimic situations typically encountered in shock-wave lithotripsy investigated by Arora, Ohl & Lohse (2007), we chose a wave of 2 atm and a wavelength of 6 mm. These values fit relatively well the shape of the tensile part tested in Arora et al (2007), although the amplitude is about 3 times less intense.…”

“…Trying to mimic situations typically encountered in shock-wave lithotripsy investigated by Arora, Ohl & Lohse (2007), we chose a wave of 2 atm and a wavelength of 6 mm. These values fit relatively well the shape of the tensile part tested in Arora et al (2007), although the amplitude is about 3 times less intense. The differences in the shock wave arriving first are more pronounced but, as the void fraction is low, we do not expect bubbles to significantly disturb the shape of the wave (this fact has been experimentally verified by Arora et al 2007).…”