Numerical investigation of multiple-bubble behaviour and induced pressure in a megasonic field

Abstract

Clarifying the mechanism of particle removal by megasonic cleaning and multiple-bubble dynamics in megasonic fields is essential for removing contaminant particles during nanodevice cleaning without pattern damage. In particular, the effect of the interaction of multiple bubbles on bubble-collapse behaviour and impulsive pressure induced by bubble collapse should also be discussed. In this study, a compressible locally homogeneous model of a gas–liquid two-phase medium is used to numerically analyse the multiple-bubble behaviour in a megasonic field. The numerical results indicate that, for bubbles with the same equilibrium radius, the natural frequency of the bubble decreases, and bubbles with smaller equilibrium radii resonate with the megasonic wave as the number of bubbles increases. Therefore, the equilibrium radius of bubbles showing maximum wall pressure decreases with an increasing number of bubbles. The increase in bubble number also results in chain collapse, inducing high wall pressure. The effect of the configuration of bubbles is discussed, and the bubble–bubble interaction in the concentric distribution makes a greater contribution to the decrease in the natural frequency of bubbles than the interaction in the straight distribution.

Interaction of cavitation bubbles with the interface of two immiscible fluids on multiple time scales

“…In most realistic circumstances, bubble dynamic behaviours are inevitably affected by boundary conditions of the flow field or external force fields such as gravity and acoustic waves (Lauterborn & Kurz 2010;Supponen et al 2016). Up to now many experimental, numerical and theoretical studies have been carried out of bubble dynamics near different boundaries, the most commonly seen of which are rigid walls (Blake, Taib & Doherty 1986;Zhang, Duncan & Chahine 1993;Hsiao et al 2014;Wang 2014;Beig, Aboulhasanzadeh & Johnsen 2018), free surfaces (Chahine 1977;Wang et al 1996;Quah et al 2018;Kang & Cho 2019), elastic membranes (Sankin, Yuan & Zhong 2010), suspended structures (Goh et al 2017;Wu et al 2017;Li et al 2019a), adjacent bubbles (Tomita, Shima & Ohno 1984;Bremond et al 2006;Ochiai & Ishimoto 2017), etc. A significant diversity of bubble collapse patterns and jetting behaviours has been revealed.…”

Experimental and numerical investigation of the dynamics of a coalesced oscillating bubble near a free surface

“…In fact, the development of the three jets makes the mesh highly distorted and irregular, so the calculation stop before 3.39ms, which causes the slight discrepancies in bubble shapes in the final collapse phase between the experiment and the simulation. The formation of one oblique jet during bubble collapse can be observed in other configurations (Brujan et al, 2018;Cui et al, 2016a;Li and Ni, 2016;Liu et al, 2016;Ochiai and Ishimoto, 2017;Rosselló et al, 2018;Tagawa and Peters, 2018), however, multiple oblique jets are rarely reported before.…”

“…In natural world, multibubble interaction is more commonly seen in the above mentioned applications. If there exists another bubble nearby, one bubble alters the ambient pressure field for the other bubble, which can significantly change the bubble dynamics and increase the bubble oscillation period (Bremond et al, 2006a;Cui et al, 2016a;Han et al, 2018;Ochiai and Ishimoto, 2017). On the contrary, the bubble period is shortened due to the existence of a free surface (Wang et al, 1996b).…”

Three-dimensional numerical analysis of wall stress induced by asymmetric oscillation of microbubble trains inside micro-vessels

“…Whereas the studies mentioned above deal with the behavior of single bubbles, others are concerned with the practical application of multiple bubbles in the clinical domain. Several experimental 27,28 and theoretical studies [29][30][31][32][33] have investigated the stress induced by trains or clouds of multiple bubbles. (See Appendix Table III for a summary of their results.)…”