Ocean Engineering最新文献

Dynamic event trigger adaptive horizon model free robust predictive control for hovercraft heading tracking using interval predictor 利用区间预测器对气垫船航向跟踪进行动态事件触发自适应地平线模型自由鲁棒预测控制

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-18 DOI: 10.1016/j.oceaneng.2024.119602

Weiqiu Zhang, Yujie Xu, Mingyu Fu, Guorong Zhang, Zhipeng Fan

This paper proposes a new dynamic event trigger adaptive horizon-based interval predictor-model free robust predictive control (IP-MFARPC) method for hovercraft heading tracking control problem without precise modeling under disturbance. Firstly, based on the input-output (I/O) data from the past period, we use partial form dynamic linearization (PFDL) to establish an online data model for the hovercraft, which is more accurate than the compact form dynamic linearization (CFDL) method. Secondly, the proposed method uses interval observers and predictors (IO&IP) to solve the prediction model offline and uses online rolling optimization to solve the optimal control sequence. During the solution process, the offline prediction model is utilized, and LMI is employed to transform robust L2 gain constraints, enhancing the control method's anti-interference ability and the accuracy of the rolling optimization process. Additionally, dynamic event triggering and adaptive prediction step mechanisms are introduced to improve online solving speed without compromising control performance. Finally, simulation results demonstrate that the IP-MFRAPC method effectively tracks the variable heading of the hovercraft under disturbances, offering faster solving times compared to methods without these mechanisms.

本文提出了一种新的基于动态事件触发自适应视距的区间预测器-无模型鲁棒预测控制（IP-MFARPC）方法，用于解决扰动下无精确建模的气垫船航向跟踪控制问题。首先，基于过去一段时间的输入输出（I/O）数据，我们使用部分形式动态线性化（PFDL）建立气垫船的在线数据模型，这比紧凑形式动态线性化（CFDL）方法更精确。其次，建议的方法使用区间观测器和预测器（IO&IP）离线求解预测模型，并使用在线滚动优化来求解最优控制序列。在求解过程中，利用离线预测模型，采用 LMI 转换鲁棒 L2 增益约束，增强了控制方法的抗干扰能力和滚动优化过程的准确性。此外，还引入了动态事件触发和自适应预测步骤机制，在不影响控制性能的前提下提高了在线求解速度。最后，仿真结果表明，IP-MFRAPC 方法能有效跟踪气垫船在干扰下的可变航向，与没有这些机制的方法相比，解算速度更快。

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引用次数: 0

Optimal design of low-speed current energy turbine based on turbine blades with different pitch angles 基于不同桨距角涡轮叶片的低速电流能源涡轮机优化设计

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-18 DOI: 10.1016/j.oceaneng.2024.119488

Guanghao Li , Guoying Wu , Lei Tan , Honggang Fan , Qingrong Kong

Darrieus water turbines face challenges in starting at low flow velocities. Helical torsional blades along the turbine axis can improve starting capability but may sometimes lead to excessive power reduction. In this paper, model tests and numerical calculations of a straight Darrieus turbine were conducted to analyze the power characteristics. Experimental results agree well with the numerical results. Turbines with linearly changing pitch angle along the height have been compared. Numerical simulations were performed to investigate the flow field of the torsional turbine with different torsion angles, and the influence of torsion angles on the instantaneous power characteristics was analyzed. The turbine with 20° pitch angle difference at blade ends showed improvement in average, maximum and minimum torque. Turbines with changing pitch angle along the blade height can facilitate the further application of vertical axis lift-type turbines in deep-sea and other environments, further maximizing the utilization of tidal current energy.

达里厄斯水轮机在低流速启动时面临挑战。沿水轮机轴线的螺旋扭转叶片可以提高启动能力，但有时可能会导致功率过度降低。本文对直达里奥斯水轮机进行了模型试验和数值计算，以分析其功率特性。实验结果与数值计算结果非常吻合。比较了桨距角沿高度线性变化的涡轮机。对不同扭转角的扭转涡轮机的流场进行了数值模拟研究，并分析了扭转角对瞬时功率特性的影响。叶片两端桨距角相差 20° 的涡轮机在平均扭矩、最大扭矩和最小扭矩方面都有所改善。沿叶片高度改变桨距角的涡轮机可促进垂直轴升降式涡轮机在深海和其他环境中的进一步应用，进一步最大限度地利用潮流能。

引用次数: 0

Experimental study on vortex-induced vibration of rough and smooth risers under variable incident angles arrangement 可变入射角布置下粗糙和光滑立管涡流诱发振动的实验研究

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-17 DOI: 10.1016/j.oceaneng.2024.119792

Chao Liu , Zebo Hu , Peng Li , Yu Wang , Zhen Liu , Lianhong Hao , Li Zhu , Yijie Huang

The interference effect between adjacent risers in a riser group has been an important research topic for a long time. To investigate the VIV responses of rough and smooth risers in a double riser system, and elucidate the impact of interference effect on rough and smooth risers. VIV experiments were conducted in a flume for rough and smooth risers under variable incident angles. The results indicate that the wake interference has the most significant impact on "lock-in" displacement when the roughness of the rough riser is lowest within the sub-critical Reynolds number range. The wake interference effect is more likely to exacerbate the vibration displacement of rough risers in the IL direction as the reduced velocity increases. Furthermore, the smooth riser at an incident angle of 0° is significantly excited by the wake from the rough riser, resulting in an expanded "lock-in" region, a shift in the dominant mode, and the excitation of higher-order frequency responses. The displacement response of the smooth riser at an incident angle of 90° is akin to that of an isolated smooth riser.

长期以来，立管组中相邻立管之间的干扰效应一直是一个重要的研究课题。为了研究双立管系统中粗糙和光滑立管的 VIV 响应，并阐明干扰效应对粗糙和光滑立管的影响。在水槽中对不同入射角的粗糙和光滑立管进行了 VIV 实验。结果表明，在次临界雷诺数范围内，当粗糙立管的粗糙度最低时，唤醒干扰对 "锁定 "位移的影响最大。随着减速度的增加，唤醒干扰效应更有可能加剧粗糙立管在 IL 方向上的振动位移。此外，入射角为 0° 的光滑立管受到粗糙立管尾流的显著激励，导致 "锁定 "区域扩大、主模态偏移以及高阶频率响应的激励。入射角为 90° 时，光滑立管的位移响应与孤立光滑立管的位移响应类似。

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引用次数: 0

Experimental study on tsunami impact on offshore box-girder bridges 海啸对近海箱梁桥影响的实验研究

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119749

Anhua Yu, Yin Gu, Xiaohe Lai, Xinyi Huang

To investigate the patterns of wave pressure exerted on the superstructure and substructure of offshore box-girder bridges under the influence of tsunamis, a scale model of 1:25 for both the pier-girder and pier model was constructed for tsunami wave impact testing. The study examined pressure and flow field characteristics at various locations on the box girders and piers under different tsunami wave conditions, analyzing the interaction and mechanisms of tsunami impact pressures between the girders and piers, as well as the effect of impact submersion coefficients on these pressures. The findings indicate significant variations in the degree to which different parts of the box girder are affected, with notably higher pressure at the Girder-Pier Connection (GPC) of the girder's bottom compared to other areas, reaching a differential of 16%. Under conditions where the pier is not submerged, the peak pressure at the top of the pier in the pier-girder model was found to be 40% higher than in the pier-only model. Therefore, ignoring the interaction between girders and piers can lead to an underestimation of the pressures caused by tsunami waves. This research is crucial for identifying bridge failure modes and developing mitigation and protection measures.

为了研究海啸影响下波浪对海上箱梁桥上部结构和下部结构施加压力的规律，我们建造了一个比例为 1:25 的墩梁和桥墩模型，用于海啸波浪冲击试验。研究考察了不同海啸波浪条件下箱梁和桥墩不同位置的压力和流场特征，分析了箱梁和桥墩之间海啸冲击压力的相互作用和机制，以及冲击浸没系数对这些压力的影响。研究结果表明，箱梁不同部位受影响的程度有很大差异，梁底梁柱连接处（GPC）的压力明显高于其他部位，差值达到 16%。在桥墩未被淹没的情况下，桥墩-梁模型中桥墩顶部的峰值压力比纯桥墩模型高出 40%。因此，忽略梁和桥墩之间的相互作用会导致低估海啸波造成的压力。这项研究对于确定桥梁失效模式以及制定缓解和保护措施至关重要。

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引用次数: 0

Time-domain simulation of nonlinear motions of moored floating body in irregular waves using rankine source method 利用秩源法对不规则波浪中系泊浮体的非线性运动进行时域模拟

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119698

Seunghoon Oh , Eun Soo Kim , Jinsoo Park , Byeongwon Park , Sungjun Jung , Min-Guk Seo , Jae Hwan Jung

This study introduces a three-dimensional time-domain Indirect Boundary Integral Equation Method (IBIEM) for simulating the motion of the floating body in both regular and irregular waves. The method systematically addresses second-order wave loads, focusing on low-frequency motions induced by low-frequency wave loads, crucial for the stability of offshore structures. Unlike traditional methods, the time-domain IBIEM simplifies the analysis by simultaneously considering all wave components of irregular waves, making the calculation of nonlinear wave loads more straightforward and intuitive. An approximate second-order equation of motion is proposed, simplifying the computational process by eliminating the need for solving boundary value problems for second-order radiation forces. The IBIEM is coupled with a quasi-static mooring model based on the elastic catenary equation, accurately capturing the influence of mooring systems on the response of the floating body. Validation against model tests and established numerical methods demonstrates the accuracy of the developed code in predicting the dynamic behavior of offshore structures. Applied to various scenarios, including a truncated cylinder, the barge, H2FPSO, and K-Semi, the results show strong agreement with experimental data, confirming the reliability and effectiveness of the method in simulating complex wave-structure interactions, making it a valuable tool for offshore structure design and analysis.

本研究介绍了一种三维时域间接边界积分方程法（IBIEM），用于模拟浮体在规则和不规则波浪中的运动。该方法系统地处理二阶波浪载荷，重点关注低频波浪载荷引起的低频运动，这对海上结构的稳定性至关重要。与传统方法不同，时域 IBIEM 通过同时考虑不规则波的所有波分量简化了分析，使非线性波载荷的计算更加简单直观。该方法提出了近似二阶运动方程，无需求解二阶辐射力的边界值问题，从而简化了计算过程。IBIEM 与基于弹性导管方程的准静态系泊模型相结合，准确捕捉了系泊系统对浮体响应的影响。通过模型试验和已有数值方法的验证，证明了开发的代码在预测近海结构动态行为方面的准确性。应用于截断圆柱体、驳船、H2FPSO 和 K-Semi 等各种情况下，结果显示与实验数据非常吻合，证实了该方法在模拟复杂波浪与结构相互作用方面的可靠性和有效性，使其成为海上结构设计和分析的重要工具。

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引用次数: 0

Numerical investigation of the propagation of internal solitary waves and their reflection by a vertical wall based on a fully nonlinear model 基于全非线性模型的内孤波传播及其被垂直墙壁反射的数值研究

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119776

Yingjie Hu , Xinyu Ma , Li Zou , Zongbing Yu , Jianshi Zhao

Propagation of internal solitary waves (ISWs) influenced by typical structures have garnered significant attention. We investigate the propagation of ISWs and their reflection by a vertical wall using multi-domain boundary element method (MDBEM). Fully nonlinear boundary conditions at the interface and free surface conditions at the top surface are considered in the simulations. Meanwhile, laboratory experiments are conducted to validate the constructed numerical model. Wave profiles, resident time, and flow fields for different initial amplitudes and density ratios are calculated and analyzed. Wave amplitudes significantly influence the nonlinear component of wave phase speed. The ratio between the nonlinear speed and the total velocity is only

4.5 %

for

a / h_{1} = 0.1

, but this value can reach

32 %

for

a / h_{1} = 0.1

. The resident time of an ISW attaching to the vertical wall decreases with the increasing initial wave amplitude and reaches a constant value for waves with amplitudes larger than

a / h_{1} = 0.6

. Particle velocity in the upper layer is opposite to that in the lower layer, and the vertical velocity becomes dominant as the wave approaches the wall. Surface displacement, presented as a surface solitary wave with an opposite phase induced by an ISW, is obtained and discussed through the numerical model.

受典型结构影响的内孤波（ISWs）的传播引起了广泛关注。我们使用多域边界元法 (MDBEM) 研究了内孤波的传播及其在垂直墙壁上的反射。模拟中考虑了界面的全非线性边界条件和顶面的自由表面条件。同时，还进行了实验室实验来验证所构建的数值模型。计算并分析了不同初始振幅和密度比下的波形、驻留时间和流场。波幅对波相速度的非线性分量有很大影响。当 a/h1=0.1 时，非线性速度与总速度的比值仅为 4.5%，但当 a/h1=0.1 时，该值可达 32%。附着在垂直壁上的 ISW 的驻留时间随着初始波幅的增大而减小，当波幅大于 a/h1=0.6 时，驻留时间达到恒定值。粒子在上层的速度与在下层的速度相反，当波浪接近墙壁时，垂直速度成为主要速度。通过数值模型得到并讨论了由 ISW 诱导的相位相反的表面孤波所产生的表面位移。

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引用次数: 0

Model predictive attitude control of unmanned surface vehicle based on short-time wave prediction 基于短时波预测的无人水面飞行器姿态模型预测控制

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119727

Liang Hong , Haitao Liu , Quanshun Yang , Jiaxuan Yao

Unmanned Surface Vehicles (USVs) are widely used in commercial and marine scientific research. In high sea conditions, USV is susceptible to significant random wave disturbances, necessitating the adoption of attitude control mechanisms to ensure safe operation. Existing control algorithms, mostly relying on Proportional Integral and Differential (PID) control and other common methods, tend to concentrate solely on the current model state, and seldom predict the future evolution of the model in combination with the state of the waves. This limitation hinders the optimization of attitude control in rough seas. To address this challenge, this paper proposes a model predictive attitude control approach grounded in Long Short-Term Memory neural network (LSTM) wave forecasting. By forecasting the wave disturbances on the USV in the coming period of time horizon and optimizing maneuvering commands, it identifies the optimal thruster actuation combination. This strategy dynamically adapts to sea conditions in real-time, enhancing the precision and accuracy of attitude control. The stability of this control strategy is validated using the discrete Lyapunov stability criterion. Simulation results demonstrate that our proposed control strategy exhibits remarkable roll and pitch reduction performance, surpassing PID control , linear quadratic regulator (LQR) control, model predictive control (MPC) without disturbance compensation, and MPC with disturbance compensation. Moreover, it maintains a superior control effect even in the presence of state feedback noise, indicating promising application prospects.

无人水面航行器（USV）广泛应用于商业和海洋科学研究。在公海条件下，USV 容易受到巨大的随机波浪干扰，因此必须采用姿态控制机制来确保安全运行。现有的控制算法大多依赖于比例积分微分（PID）控制和其他常用方法，往往只关注当前的模型状态，很少结合海浪状态预测模型的未来演变。这一局限性阻碍了波涛汹涌海面上姿态控制的优化。为应对这一挑战，本文提出了一种基于长短期记忆神经网络（LSTM）波浪预测的模型预测姿态控制方法。通过预测 USV 在未来一段时间内受到的波浪干扰并优化操纵指令，该方法确定了最佳推进器驱动组合。该策略可实时动态适应海况，提高姿态控制的精度和准确性。利用离散李亚普诺夫稳定性准则验证了这一控制策略的稳定性。仿真结果表明，我们提出的控制策略具有显著的减少侧倾和俯仰的性能，超过了 PID 控制、线性二次调节器（LQR）控制、不带干扰补偿的模型预测控制（MPC）和带干扰补偿的模型预测控制（MPC）。此外，即使在存在状态反馈噪声的情况下，它也能保持卓越的控制效果，显示出广阔的应用前景。

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引用次数: 0

Experimental Investigation of the hydrodynamic and acoustic performance of a Gate Rudder® system over a conventional rudder 门舵®系统相对于传统尾舵的水动力和声学性能实验研究

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119742

Ivan Santic, Salvatore Mauro, Mario Felli

The Gate Rudder® is a new concept of energy saving device and manoeuvring system, consisting of two asymmetric and independent blades at each side of a propeller which combines the advantage to deliver additional thrust, similar to an accelerating ducted propulsor, and to enhance ship manoeuvrability and seakeeping ability due to the individual control of each rudder blades.

The present study reports the results of a comprehensive experimental survey in which the hydrodynamic and hydro-acoustic performances of a Gate Rudder® system (GRS) were investigated with respect to a conventional rudder (CRS), for a reference container vessel. The survey, that was conducted in the framework of the EU H2020 Research Project “GATERS”, included detailed flow measurements by 2D-PIV and Stereo-PIV, cavitation tests and acoustic measurements on a scaled model of a target container ship. The tests matrix covered different rudder/rudder-blade angles, speeds and displacements. The study highlights the beneficial effects provided by the installation of a Gate Rudder® over a conventional rudder in terms of sound mitigation and reveals the fundamental underlying hydrodynamic mechanisms of the propeller wake interaction with the Gate Rudder blades under different operative conditions.

The results provide useful insights on how to improve the hydrodynamic and acoustic performance of a GRS.

门舵（Gate Rudder®）是一种新概念的节能装置和操纵系统，由螺旋桨两侧的两个不对称独立桨叶组成，具有提供额外推力（类似于加速管道推进器）的优势，并可通过对每个舵叶的单独控制来增强船舶的操纵性和稳航能力。本研究报告汇报了一项综合实验调查的结果，其中针对一艘集装箱船，调查了门舵®系统（GRS）与传统尾舵（CRS）的水动力和水声性能。这项调查是在欧盟 H2020 研究项目 "GATERS "的框架内进行的，包括通过 2D-PIV 和立体 PIV 进行的详细流动测量、气蚀测试以及对目标集装箱船缩放模型进行的声学测量。测试矩阵包括不同的舵/舵叶角度、速度和位移。该研究强调了安装闸舵（Gate Rudder®）相对于传统尾舵在消声方面的有益效果，并揭示了不同工作条件下螺旋桨尾流与闸舵叶片相互作用的基本流体力学机制。

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引用次数: 0

Using STPA for hazard identification and comparison of hybrid power and propulsion systems at an early design stage 在早期设计阶段利用 STPA 对混合动力和推进系统进行危险识别和比较

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119752

Anna Sophia Hüllein , Børge Rokseth , Ingrid Bouwer Utne

The decarbonization of the shipping industry is a hot topic and new emission reduction goals, regulations, and initiatives all over the world underline its importance. These goals apply to the ocean going fleet, as well as coastal shipping and fisheries. Both academia and industry, work on the development and testing of new technologies to reach emission reduction targets. Besides technical feasibility and economic viability, the safety of new power and propulsion systems must be considered in this process. In this paper, the Systems Theoretic Process Analysis (STPA) method is used for hazard identification and comparison of two alternative hybrid power and propulsion systems for a small-scall fishing vessel. The assessment method allows for identifying focus areas for hazard reduction in a systematic manner. System safety requirements derived from the assessment can be considered when designing power and propulsion systems. Based on the results, a discussion of the method and the usefulness of the results is given. The main findings are that the assessment provides valuable insights into the hazards introduced by new power and propulsion systems in a qualitative manner. For a quantification of the risk, further work and an extension of the assessment are needed. The STPA results show that especially the control of the power sources and their interactions internally and externally with the consumer side are crucial. Therefore, special attention should be given to the design of the automated control system, feedback system, and user interaction with the system.

航运业的去碳化是一个热门话题，世界各地的新减排目标、法规和倡议都强调了其重要性。这些目标既适用于远洋船队，也适用于沿海航运和渔业。学术界和工业界都致力于开发和测试新技术，以实现减排目标。在此过程中，除了技术可行性和经济可行性外，还必须考虑新动力和推进系统的安全性。本文采用系统理论过程分析（STPA）方法，对两套可供选择的混合动力和推进系统进行危险识别和比较。这种评估方法可以系统地确定减少危害的重点领域。在设计动力和推进系统时，可考虑评估得出的系统安全要求。根据评估结果，对评估方法和评估结果的实用性进行了讨论。主要结论是，该评估以定性的方式对新型动力和推进系统带来的危险提供了有价值的见解。要量化风险，还需要进一步的工作和扩展评估。STPA 的结果表明，特别是对动力源的控制及其与用户方的内部和外部互动至关重要。因此，应特别关注自动控制系统、反馈系统和用户与系统交互的设计。

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引用次数: 0

Experimental and numerical investigation of dynamic characteristics and safe mooring criteria of moored outfitting ships under swell conditions 膨胀条件下系泊舾装船的动态特性和安全系泊标准的实验和数值研究

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.oceaneng.2024.119771

Yunpeng Zhu , Xiaojun Li , Yan Zhu , Ming Wen , Hulin Chen , Xiaotong Yu , Da Chen

Outfitting ships are characterized by a small draft and a large wind area. As a kind of unpowered ship, when subjected to strong lateral loads, excessive sway motion could cause cable breakage, resulting in potential ship damage or casualties. In this paper, physical and numerical model experiments have been carried out to investigate the effects of swells on moored outfitting ships. The data is analyzed in time and frequency domains to discover the relationship between swells, mooring patterns, ship motions and mooring forces. Subsequently, a numerical model is developed in AQWA, and in conjunction with the physical model experiments, safe mooring criteria for outfitting ships under swell are proposed. Results show that both reducing the sea severity and increasing the number of cables is effective in reducing the risk of cable breakage. The horizontal and heave motions of outfitting ships are controlled by swell period, while the roll and pitch motions are mainly controlled by own parameters. For the cables at different locations, the bow/stern line, breast line and spring line are mainly controlled by sway/yaw motions, sway motion and surge motion, respectively. Additionally, the safe mooring criteria could be widely applied to outfitting quays to ensure the safe operation.

舾装船的特点是吃水小、风区大。舾装船作为一种无动力船舶，在承受强大侧向载荷时，过大的摇摆运动可能会导致缆绳断裂，从而造成潜在的船舶损坏或人员伤亡。本文通过物理和数值模型实验，研究了膨胀对停泊的舾装船的影响。对数据进行了时域和频域分析，以发现浪涌、系泊模式、船舶运动和系泊力之间的关系。随后，在 AQWA 中开发了一个数值模型，并结合物理模型试验，提出了在涌浪条件下舾装船舶的安全系泊标准。结果表明，降低海浪严重程度和增加缆绳数量都能有效降低缆绳断裂的风险。舾装船舶的水平和倾斜运动受涌浪周期控制，而滚动和俯仰运动主要受自身参数控制。对于不同位置的缆线，艏/艉线、胸线和弹线分别主要受摇摆/偏航运动、摇摆运动和涌浪运动的控制。此外，安全系泊标准可广泛应用于码头舾装，以确保安全运行。

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引用次数: 0