Two initially spherical bubbles rising in quiescent liquid

Abstract

A pair of bubbles starting from rest and rising side-by-side in a liquid have been shown earlier to display spherical and ellipsoidal shapes. In contrast to earlier computational studies on the two-dimensional dynamics of a pair of bubbles, we study the fully three-dimensional motion of the bubbles in the inertial regime. We reveal the destabilizing nature of the interaction between the wakes of the bubbles, which causes them to rise in an oscillatory path. Such three dimensionality sets in earlier in time than for a single bubble and also at a lower inertia. The interaction leads to a mirror symmetry in the trajectories of the two bubbles, which persists for some time even in the high inertia regime where each path is chaotic. The e↵ect of the inertia and initial separation on the mirror symmetry of the path, the vortex shedding pattern and the attraction/repulsion between the bubbles are examined. The bubble rise has been interestingly observed to be symmetrical about the plane perpendicular to the separation vector for all separation distances considered in the present study.

Dynamics of Rising Bubbles in a Quiescent Slag Bath with Varying Thermo-Physical Properties

“…The same group presented further numerical investigations focusing on path instabilities and break-up phenomena. [24,25] Their results also showed the importance of a 3D approach in modeling bubble dynamics, since except for the axi-symmetric one, all the regimes present an asymmetric and inherently 3D nature. Bubble dynamics have also been investigated in molten metal systems, [26][27][28][29][30][31][32][33][34] which require sophisticated apparatus, such as X-ray radiography and ultrasound velocimetry, to measure the flow and provide data to validate numerical investigations, as in the previous work of the author.…”

Interaction of two oscillating bubbles rising in a thin-gap cell: vertical entrainment and interaction with vortices

“…Such complexities are not easy to take into account to study interactions, yet they are expected to contribute significantly to them. While progress has been achieved in numerical simulations to handle them (Smolianski, Haari & Luukka 2005;Cheng, Hua & Lou 2010;Chen et al 2010;Yu, Yang & Fan 2011;Gumulya et al 2017;Tripathi et al 2017), it remains that a conceptual global framework aiming at capturing generic mechanisms during the interaction of two unstable bubbles, free to move and deform, is still lacking. Studying the interaction between two freely rising bubbles which exhibit oscillatory motion and develop a complex wake when isolated is a very challenging problem.…”

Hydrodynamic interaction of bubbles rising side-by-side in viscous liquids

“…They also suggested that the effects of potential and wake ejection tend to form horizontal clusters, but could be neutralised by the agitation effect induced by neighbouring bubbles. Tripathi et al (2017) employed 3D DNS simulation for two initially spherical bubbles rising side-by-side and found that the bubble interaction is linked to strong interacting vortices. Recently, Zhang et al (2019) studied the evolution of the vortex associated with the interaction of bubbles rising sideby-side by the fully three-dimensional DNS simulations.…”

“…The opposing findings reported in the literature and the advancement of experimental techniques prompted us to undertake the present study. Moreover, to the best of our knowledge, the simulation study of Tripathi et al (2017) and Zhang et al (2019) is the only work addressing the interaction between deformed bubbles. In the present study, a spherical bubble pair and a deformed bubble pair are experimentally studied to investigate their hydrodynamic interaction.…”