2022, Volume 17, Issue 3
Water-air-bubble mixed flow is a complex flow generated by the intense interaction between marine structures and surrounding fluids. It involves a large span of temporal and spatial scale, and has many influencing factors on its generation and evolution. Combining the flow fields of ship and ocean engineering, water-air-bubble mixed flow affects the performance of structures in many aspects, giving the subject strong research significance. This paper reviews the research progress of the mechanism exploration and numerical simulation methods. In terms of mechanism exploration, the present scientific understanding of the formation and evolution mechanisms and the analysis of the phenomenon characteristics of water-air-bubble mixed flow around marine structures are introduced. In terms of numerical simulation methods, the development route and key technical problems of the algorithms are introduced according to insights from elaboration to modeling. Finally, future research prospects are proposed.
High-speed hydrodynamics and its corresponding complex fluid-structure interactions (FSI) are challenging topics associated with naval architecture and ocean engineering, typically characterized by large deformations, moving boundaries, strong convection and multiple fluid media. Since traditional mesh-based numerical methods possess limited ability to accurately simulate such strongly nonlinear problems, it is imperative to develop meshless numerical schemes with high fidelity and robustness to tackle this dilemma. As one of the most promising truly meshless methods, smoothed particle hydrodynamics (SPH) shows apparent advantages in high-speed hydrodynamics problems thanks to its Lagrangian nature. In the present paper, the attention is particularly focused on the latest advances of several SPH techniques with respect to the following high-speed hydrodynamics problems: vessel-induced waves and wakes, the water entry process of projectiles, and underwater explosion and its resulting structural damage; in addition, the future prospects of SPH are provided in the last part of the paper.