Nanobubble Collapse Induced Erosion near Flexible and Rigid Boundaries: A Molecular Dynamics Study

In this work, we performed molecular dynamics simulations to study the dynamics of a shock wave-induced single nanobubble collapsing near one flexible and two rigid boundaries. The flexible boundary consisted of polyethylene, and the rigid boundaries were made of aluminum and iron. The shock waves impinging on the nanobubble inside a molecular system were generated using a momentum mirror approach. For two relative wall distances, we studied the dynamics of the shock-induced single nanobubble and its collapse near the flexible and the rigid boundaries. The atomic velocity contours surrounding the single nanobubble and the collapse-induced damage on the boundaries were analyzed. We obtained this collapse-induced damage from ten collapsing nanobubbles. Results showed that the relative wall distance affected the single nanobubble's collapse dynamics near the boundaries. A generated nanojet was directed on the surfaces during the collapse process. From the collapse-induced damage point of view, the depth damage of the polyethylene, iron, and aluminum boundaries for the relative wall distance of gamma = 1.3 were 6.0, 0.47 and 0.63 nm, respectively. It was observed that the extensive collapse-induced damage occurred only on the polyethylene boundary.

Automated summary

In this study, molecular dynamics simulations were used to investigate the behavior of a single nanobubble collapsing near flexible and rigid boundaries under a shock wave. The results showed that the relative wall distance had an impact on the collapse dynamics of the nanobubble near the boundaries, and a nanojet was generated during the collapse process. From a damage perspective, the depth damage of the polyethylene, iron, and aluminum boundaries for a relative wall distance of 1.3 were 6.0, 0.47, and 0.63 nm, respectively, with extensive damage only occurring on the polyethylene boundary.