Harmonic structure of the nonlinear force on a fixed ship-shaped floating production, storage and offloading vessel under dispersive phase-focused wave groups
Harmonic structure of the nonlinear force on a fixed ship-shaped floating production, storage and offloading vessel under dispersive phase-focused wave groups
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DOI：
10.1063/5.0141342
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发表时间：
2023-04
影响因子：
4.6
通讯作者：
Hao Chen;L. Qian;Deping Cao
中科院分区：
文献类型：
--
作者：
Hao Chen;L. Qian;Deping Cao
本文对一艘具有代表性的固定式简化浮式生产储卸船（FPSO）船体在色散相聚焦波群作用下的水动力谐波结构进行了数值研究。高保真数值模型利用开源工具箱OpenFOAM中的两相流求解器。使用数值模型计算了一系列情况，其中研究了波浪陡度，船首直径和FPSO长度的影响。研究发现，给定一个FPSO，在不同的波浪陡度下，无量纲内联力在时间发展方面表现出显著的相似性。内联力的谐波结构仅与入射波群的陡度和船首直径有微弱的关系，而与FPSO的长度有很大的关系。当[公式：见文]，其中L是FPSO的长度，kp是峰值频率的波数，入射波组被FPSO明显衍射。整个波结构相互作用过程在很大程度上是线性的，其中不同谐波之间的传递很少看到。然而，当kpL进一步降低到0.57时，FPSO对远场入射波群的整体扰动减少，但局部FPSO后部发生强烈的非线性流动，其中下游驻点处发生严重的上升。内联力的高次谐波被激发，相互作用过程变得更加非线性。
This paper presents a numerical investigation on the harmonic structure of hydrodynamic forces on a fixed and simplified representative floating production, storage and offloading (FPSO) vessel hull under dispersive phase-focused wave groups. The high-fidelity numerical model utilizes the two-phase flow solver in the open-source toolbox OpenFOAM. A series of cases were computed using the numerical model, where the effects of wave steepness, bow diameter, and length of the FPSO are investigated. It is found that given an FPSO under different wave steepness, the non-dimensional inline force exhibits remarkable similarity in terms of the temporal development. The harmonic structure of the inline force is only weakly dependent on the steepness of the incident wave group and the bow diameter, but strongly dependent on the FPSO length. When [Formula: see text], where L is the length of the FPSO and kp is the wave number at peak frequency, the incident wave group is diffracted significantly by the FPSO. The entire wave–structure interaction process is largely linear, where transfer between different harmonics is rarely seen. However, when kpL is further reduced to 0.57, globally the disturbance of the FPSO on the far field incident wave group is reduced, but locally a strongly nonlinear flow occurs at the rear of the FPSO, where severe run-up occurs at the downstream stagnation point. Higher-order harmonics of inline forces are excited, and the interaction process becomes much more nonlinear.