Experimental and numerical investigation on bubble dynamics near plates with a hole under near-field underwater explosion

Abstract

Shock waves inflict catastrophic impacts and severe damage on ships. To investigate the following bubble dynamics near damaged ship structures subjected to shock waves, underwater explosion experiments were conducted using 2.5 g TNT detonated beneath clamped elastoplastic plates with varying hole dimensions and shapes. The experimental results indicated that the dimension and shape of these holes significantly influence the morphology of resulting water jets. A finite element model was developed and validated, followed by a series of numerical simulations to systematically investigate the evolution of water jets and the dynamic response of clamped elastoplastic plates across varying stand-off distances, hole dimensions, and explosive equivalents. The findings reveal that the interaction of various loads and boundary conditions lead to distinct water jets: upward, counter, and downtown water jets. Based on these findings, a criterion was proposed to classify jet morphologies beneath clamped elastoplastic plates. Finally, full-scale ship numerical simulations were performed at varying distances to assess the damage modes associated with various jet types. This investigation offers certain guidance for the blast-resistance ship design.