Bubble detachment from solid surfaces induced by impacting particles

In this paper, the coupled volume-of-fluid and level set method, immersed boundary method and discrete element method is extended to an axisymmetric configuration to investigate bubble detachment from solid surfaces induced by particle impact. The post-impact dynamics is systematically investigated over a range of Weber numbers ( We ), particle wettabilities ( theta Subscript p θ p θ ₚ ), density ratios ( k Subscript rho k ρ kρ ) and size ratios ( k Subscript r k r kᵣ ). The results reveal three distinct detachment modes: capillary-wave detachment (CWD), bubble-rebound detachment (BRD) and particle-rebound detachment (PRD). At low We , early spreading over the particle releases surface energy and excites capillary waves that drive contact-line motion and rapid detachment. The spreading follows a power law, with the exponent increasing with We , reflecting the increasing contribution of impact inertia to the spreading process. As We increases, inertial compression suppresses capillary-wave-induced momentum reversal and the detachment mode shifts to BRD, where momentum reversal is achieved through the release of stored deformation energy. At sufficiently high We , particle rebound from the substrate injects a strong upward momentum into the flow, leading to PRD. Kelvin impulse analysis is employed to quantify the evolution of vertical momentum and establish a unified interpretation of the detachment process. A detachment capability factor is further proposed to characterise the competition between interfacial energy release and inertial suppression. Regime maps in the ( We , theta Subscript p θ p θ ₚ ), ( We , k Subscript rho k ρ kρ ) and ( We , k Subscript r k r kᵣ ) parameter spaces are constructed, demonstrating that mode transitions are governed by the balance between capillary-wave-driven momentum generation and inertia-induced suppression.