Hydrodynamic analysis of a novel box-type floating marine airport

Abstract

Very Large Floating Structure (VLFS) plays a crucial role in mitigating land resource scarcity in developed coastal areas. This paper introduces an innovative VLFS concept consisting of numerous concrete box-type floats interconnected by steel tie rods, designed for a 4000-m-long floating marine airport. Based on three-dimensional potential flow theory, two numerical models for the VLFS are established: the single-float model and the multi-float model interconnected by joints, where each float treated as rigid. The research explores the impact of wave direction, wave period, and real sea conditions on the hydrodynamic response of the VLFS. Additionally, this paper focus on the discrepancies in dynamic characteristics between single-float and muti-float, and investigate the special response principles of the muti-float model that closely resemble the actual hydrodynamic features of VLFS. The findings show that local deformation in the VLFS results in elevated wave loads on the structure, posing a significant challenge in designing the VLFS mooring system. Higher structural stiffness correlates with decreased mean and pulsation values of mooring cable tension. Incident waves at 0° induce local deformation on the wave-facing side of the VLFS; however, the deformation rapidly dissipates, exerting minimal impact on the floats supporting the airport runway—thus, creating an indirect wave-absorbing mechanism. When waves incident at 90°, the VLFS bends, adversely impacting the operations of marine airports and causing uneven stresses on the connectors, making them susceptible to fracture and damage. Hence, it is advisable to install marine airports parallel to prevailing wave directions. Furthermore, the hydroelastic behaviour of VLFS contribute to alleviating internal stresses within the structure. The focus of future research lies in balancing the impact of VLFS hydroelasticity on both system motion performance and structural internal stresses. The VLFS concept presented in this study performs effectively under various real sea conditions. The rationality and feasibility of the proposed VLFS concept are substantiated. The study lays the foundation and presents ideas for the future development of marine space.