Dynamic responses of a floating rigid hull subject to a pulsating bubble

• Published in: Physics of fluids (1994) Vol. 37; no. 6
• Main Authors: Liu, Yun-Long, Qin, Hao, Yang, Di, Tian, Zhao-Li
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.06.2025
• Subjects: Finite element method; Floating structures; Fluid-structure interaction; Free surfaces; Mathematical analysis; Numerical models; Rigid-body dynamics; Underwater explosions
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/5.0267593

A high-pressure pulsating bubble near the free surface casts intense nonlinear impacts on adjacent floating structure, and the rigid-body motion caused by the pulsating bubble jeopardize the stability of floating structure and even lead to a catastrophic sinkage. To address these critical fluid–structure interaction challenges, this study develops a novel numerical framework combining a modified penalty immersed boundary method with the Eulerian finite element method to simulate the interaction between a rigid hull and a pulsating bubble. The numerical model is validated by experiments between a steel hull and a small-weight underwater explosion. The experiment and simulations reveal two critical hydrodynamic phenomena: the formation of transient “side cavity” while bubble shrinking and the subsequent oblique jet toward broadside, both exhibiting strong correlations with the dynamic responses of hull. Parametric investigations on non-dimensional standoff parameters are conducted to elucidate the dynamic patterns of this cavity and the rigid motions of a Wigley hull. Our analysis demonstrates that while the motion of the rigid hull is correlated with the collapsing patterns of the side cavity, the hull's dynamic responses are predominantly driven by the accelerated flow field and the time-varying buoyancy environment induced by the heaving free surface surrounding the pulsating bubble. Yet, this jet is still worth further investigations, for that it might cause fatal damage to the local structures and endanger the vessels.