Applied Ocean Research最新文献_第9页

Autonomous detection, localization and tracking of ships by underwater acoustic sensing using vector sensor array

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104389

Shweta Lokhande , A. Malarkodi , G. Latha , S. Srinivasan

Maritime security and surveillance demand advanced technologies for ship detection, localization, and tracking in vast oceanic environments. Acoustic sensing, particularly with Vector Sensor Arrays (VSAs), has become an efficient solution because it provides directional information of underwater sound signals. This paper presents the harbor trial of an indigenously developed, autonomous underwater vector sensor array system for detection, localization, and tracking of ships using acoustic sensing for coastal surveillance applications. The VSA system was deployed for one month, in the harbor area of Chennai, Acoustic pressure and three components of particle velocities measured by the vector sensor array are analyzed to study the different ship noise and localization of ships. In order to localize the ship noise, Direction of Arrival (DoA) and Range have been determined. DoA is estimated through MUSIC (Multiple Signal Classification) with Singular Value Decomposition (SVD) algorithm that leverage the directional sensing capabilities of VSA. Furthermore, ship tracking is performed for sequential detection and estimation to ensure continuous monitoring of ship movements. Also source level is estimated for the ships. Various acoustic levels and spectral densities are observed from the ships based on their speed, length, and distance from the VSA system. The results have been validated with the Automatic Identification System (AIS) data and they show that detection, localization and tracking of the ships using the VSA give good results. Autonomous acoustic sensing using VSA illustrates to be a promising approach for coastal surveillance and maritime security applications.

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引用次数: 0

Current measurement by use of synchronous wave probes: Method and example of laboratory experiments for progressive or partially standing waves

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104386

A. Cuevas , V. Rey , F. Ardhuin , J. Touboul

In the context of studies of interactions between waves and currents, a method of calculation of the current through synchronous free surface deformation measurements at various locations is proposed and discussed in the case of either progressive or partially standing waves, and for either homogeneous or vertically sheared current. For partially standing waves, the method takes advantage of separation of incident and reflected wave method through minimization algorithms, which are still applicable in the limit case of a progressive wave. Discussions on the accuracy of the method are based on comparisons to laboratory experiments including regular and irregular waves in following or opposite current conditions. The vertically averaged current is recovered since current has a significant influence on the wave celerity. Vertically shear has less influence on the wave celerity in comparison to the averaged current in the experimental conditions considered, and is hardly directly recovered because of the noise inherent to the measurements. However the shear can be estimated through the calculated vertically averaged current which depends on frequency in the presence of shear. The present study concerns the unidirectional case, including regular or irregular waves.

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引用次数: 0

Evaluation of wave-induced flow through marine porous media accounting for transition of seepage properties across multiple flow regimes 考虑多流型渗流特性转变的海洋多孔介质波浪渗流评价

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-12-01 DOI: 10.1016/j.apor.2024.104346

Shihuan Zou , Maosong Huang , Zhenhao Shi

Wave-induced flow through marine porous media has been attracting coastal engineers and researchers because of their strong correlation with scouring, internal erosion, piping and other destructions of marine porous structures. Previous studies chose Darcy-Forchheimer equation for wave-induced seepage behavior analyses because of its simplicity and perceptiveness. However, numerous experiment observations suggested that significant flow regime transition occurred in porous media with high variations in porosity and particle size, while Darcy-Forchheimer equation is only applicable to flow within Forchheimer regime. In this paper, a mathematical model linking the resistance of porous medium to its porosity and particle size is proposed to characterize the seepage properties across Darcy and Forchheimer regime under wave loadings. The proposed seepage model is then incorporated into volume-averaged Reynolds-averaged Navier-Stokes equations, and thus enabling evaluating fluid motions in waves and marine porous media via a unified framework. Through validation against experimental observations, analytical solutions and well accepted computed results in the literature, the proposed model is shown to replicate the characteristics of resistance of porous media with different porosities and particle sizes under different flow regimes. Numerical analyses are conducted to elucidate that seepage velocities of wave-induced flow in marine porous materials can be over- or under-estimated if not considering transitional seepage properties across multiple flow regimes. Such discrepancies can become significant when strong variations occur in porous media with respect to particle size and/or porosity.

波浪诱导的海洋多孔介质流动与海洋多孔结构的冲刷、内部侵蚀、管道等破坏密切相关，一直吸引着海岸工程师和研究人员的注意。以往的研究选择Darcy-Forchheimer方程进行波动渗流行为分析，因为它简单、直观。然而，大量的实验观察表明，在孔隙度和粒径变化较大的多孔介质中会发生明显的流型转变，而Darcy-Forchheimer方程仅适用于Forchheimer流型内的流动。本文提出了一种将多孔介质的阻力与其孔隙度和粒径联系起来的数学模型，以表征波浪荷载作用下达西和福奇海默状态下的渗流特性。然后将所提出的渗流模型整合到体积平均reynolds -平均Navier-Stokes方程中，从而可以通过统一的框架来评估波浪和海洋多孔介质中的流体运动。通过对实验观察、解析解和文献中广为接受的计算结果的验证，表明所提出的模型可以复制不同孔隙率和粒径的多孔介质在不同流动状态下的阻力特征。数值分析表明，如果不考虑多流型的过渡渗流特性，波浪渗流在海洋多孔材料中的渗流速度可能会被高估或低估。当多孔介质中颗粒大小和/或孔隙度发生强烈变化时，这种差异就会变得显著。

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引用次数: 0

Corrigendum to “Wave Energy Potential and the Role of Extreme Events on South America's Coasts. A Regional Frequency Analysis” [Applied Ocean Research, Volumen 153, December 2024] “波浪能势和南美洲海岸极端事件的作用”的勘误表。区域频率分析”[应用海洋研究，vol . 153, December 2024]

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-12-01 DOI: 10.1016/j.apor.2024.104338

Valeria Mundaca-Moraga , Rodrigo Abarca-del-Rio

引用次数: 0

A novel leg design for reducing consolidation settlement of deeply embedded spudcan foundations in clayey seabed soils 一种减少海底粘土深埋桩基础固结沉降的新型桩腿设计

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-11-30 DOI: 10.1016/j.apor.2024.104335

Yu Ping Li , Jiang Tao Yi , Yong Fu , Khursheed Zeeshan , Yuntao Yuan

Field monitoring data has demonstrated excessive spudcan settlement during jack-up rig operation. However, there are no methods available for operators to reduce the consolidation settlement development. This paper presents a centrifuge and numerical model investigation aimed at reducing spudcan settlement. Initially, two centrifuge model tests were carried out to realistically replicate spudcan "penetration-unloading-consolidation" stages in an offshore field. The test results show that the spudcan consolidation settlement was partially reduced by the presence of an existing lattice leg extending from the top of spudcan footing. Based on this, it is suspected that a sleeve of a certain length extending from the top of the spudcan footing could be used to further reduce spudcan consolidation settlement. This work was accomplished by conducting small strain finite element analysis, the feasibility and reliability of the numerical model were first verified by comparing with centrifuge model test results. Subsequently, numerical models of spudcan installation and consolidation were conducted for both plain and sleeved-spudcan footings, under various soil strengths, operational loads, and embedment depths. Numerical results show that the top-mounted sleeve helped to prevent soil above the spudcan footing from moving downward, thereby reducing spudcan settlement. Based on the numerical results, an explicit equation assessing sleeved-spudcan consolidation settlement was established, as a function of sleeve area ratio and correlated well with that of a plain spudcan. This study provides a feasible and reliable numerical method for assessing spudcan consolidation settlement as well as an effective leg design to reduce settlement.

现场监测数据显示，自升式钻井平台运行过程中，铲管沉降过多。然而，对于运营商来说，目前还没有有效的方法来减少固结沉降的发展。本文介绍了一种旨在减少球囊沉降的离心机和数值模型研究。最初，在海上油田进行了两次离心机模型试验，以真实地模拟spudcan的“穿透-卸载-固结”阶段。试验结果表明，从铲脚顶部延伸出的现有格架腿的存在，部分地减少了铲脚固结沉降。在此基础上，推测可以采用一定长度的套管从铲底基础顶部伸出，进一步减小铲底固结沉降。本工作通过进行小应变有限元分析来完成，首先通过与离心机模型试验结果的对比验证了数值模型的可行性和可靠性。随后，在不同的土壤强度、运行荷载和埋深下，对平铲和套铲基础进行了安装和固结的数值模型。数值结果表明，顶置套筒有助于防止铲球基础上方土体下移，从而减少铲球沉降。在此基础上，建立了套管-铲土固结沉降的显式方程，该方程是套管面积比的函数，且与普通铲土固结沉降具有良好的相关性。本研究提供了一种可行、可靠的数值方法来评估铲斗固结沉降，并为减小沉降提供了有效的支腿设计。

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引用次数: 0

An integrated system theoretic accident model and process (STAMP)-Bayesian network (BN) for safety analysis of water mist system on tanker ships 综合系统理论事故模型与过程(STAMP)-贝叶斯网络（BN）的油船水雾系统安全分析

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-11-30 DOI: 10.1016/j.apor.2024.104344

Bulut Ozan Ceylan , Sukru Ilke Sezer , Emre Akyuz

A water mist on tanker ships is a specialized fire suppression system intended to mitigate fire hazards on board. This innovative safety measure disperses microscopic water droplets, creating a mist that rapidly absorbs heat and suppresses fires by reducing oxygen levels and cooling the surrounding area autonomously. This paper attempts to perform a comprehensive safety analysis of the water mist system on a tanker ship under the system theoretic accident model and process (STAMP) and Bayesian network (BN) robust modeling, which is capable of presenting a dynamic structure comprising complex elements. In the paper, whilst the STAMP is utilized to determine failure scenarios by establishing a hierarchical control and feedback model structure, the BN quantifies the probabilities of potential failures based on the outcomes of STAMP. A water mist system in tanker ships is analyzed under STAMP-BN modeling since it is an essential part of the ship, including an advanced system comprising elements of human, software, and hardware. The research results indicate that the failure probability of the water mist system has a failure probability of 3.93E-02. Besides its robust theoretical background, the research findings will provide a helpful reference for maritime safety managers, safety inspectors, technical inspectors, HSEQ managers, and ship crew on improving fire-fighting safety in tanker ships.

油船上的细水雾是一种专门用于减轻船上火灾危险的灭火系统。这种创新的安全措施可以分散微小的水滴，形成一层薄雾，迅速吸收热量，通过降低氧气水平和自动冷却周围区域来抑制火灾。本文试图在系统理论事故模型与过程（STAMP）和贝叶斯网络（BN）鲁棒建模的基础上，对油轮水雾系统进行全面的安全分析，该模型能够呈现一个由复杂元素组成的动态结构。在本文中，STAMP通过建立层次控制和反馈模型结构来确定故障场景，而BN根据STAMP的结果量化潜在故障的概率。油船水雾系统是油船的重要组成部分，是一个由人、软件和硬件组成的先进系统，在STAMP-BN模型下对其进行了分析。研究结果表明，细水雾系统的失效概率为3.93E-02。研究结果将为海上安全管理人员、安全检查员、技术检查员、HSEQ管理人员和船员提高油轮消防安全水平提供有益的参考。

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引用次数: 0

Numerical study on 2:1 nonlinear parametric resonant responses of a Spar buoy in waves 波浪中桅杆浮标2:1非线性参数共振响应的数值研究

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-11-30 DOI: 10.1016/j.apor.2024.104345

Jingrui Zhao, Zhishuai Liu, Xiang Lin

This paper investigates the 2:1 parametric resonant behaviors of a Spar buoy in waves from the perspective of nonlinear dynamics. A coupled dynamic model of an experimental Spar buoy is established, incorporating its mooring system and nonlinear hydrostatic stiffness. The 2:1 parametric resonant behaviors of the Spar buoy are simulated in the time domain. To elucidate the mechanical mechanisms, the governing equation of pitch motion is simplified to a damped Mathieu-Duffing equation. The first-order analytical solution of the damped Mathieu-Duffing equation is derived using the perturbation method when the incident wave frequency approaches twice the pitch natural frequency of Spar buoys. A refined stability chart is generated in the parameter plane, alongside a time-efficient quantitative evaluation method for parametric resonant responses. The nonlinear pitch motions of the Spar buoy are predicted using this simplified approach and validated against the coupled dynamic model under both regular and irregular wave conditions, the bifurcation and jumping phenomenon are simulated. The findings indicate that high-order nonlinear stiffness can trigger a steady-state non-zero solution for the parametric resonant amplitude, leading to significant pitch motion during Mathieu instability. Furthermore, wave elevation can induce pitch motion resonance even when heave motion is non-resonant. The irregular waves can also excite a relatively moderate parametric resonance of pitch motion for the Spar buoy. This proposed methodology may assist designers in assessing parametric instability during the preliminary design stage for Spar buoys.

本文从非线性动力学的角度研究了桅杆浮标在波浪中的2:1参数共振行为。建立了考虑系泊系统和非线性静水刚度的实验浮筒耦合动力学模型。在时域上模拟了Spar浮标的2:1参数共振行为。为了阐明其力学机理，将俯仰运动的控制方程简化为阻尼的Mathieu-Duffing方程。采用摄动法，导出了当入射波频率接近浮标俯仰角固有频率的两倍时，阻尼Mathieu-Duffing方程的一阶解析解。在参数平面上生成了精细化的稳定性图，同时提供了一种高效的参数共振响应定量评价方法。利用该简化方法预测了Spar浮标在规则波和不规则波条件下的非线性俯仰角运动，并通过耦合动力学模型进行了验证，模拟了其分岔和跳变现象。研究结果表明，高阶非线性刚度可以触发参数共振振幅的稳态非零解，导致Mathieu失稳期间出现明显的节距运动。此外，波浪高程即使在升沉运动不发生共振的情况下也会引起俯仰运动共振。不规则波浪也能激发相对温和的纵摇运动参数共振。这种提出的方法可以帮助设计者在Spar浮标的初步设计阶段评估参数不稳定性。

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引用次数: 0

Numerical modeling of sediment dumping in deep water through a rock-fall pipe for subsea pipeline burial 海底管道埋置落石管深水输沙数值模拟

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-11-29 DOI: 10.1016/j.apor.2024.104328

Runyu Xie, Pengzhi Lin

This paper presents a numerical study of sediment dumping in deep water through a rock-fall pipe for the burial of a subsea pipeline. A coupled CFD-DEM model is employed to model the interaction among sediments, ambient flow, pipeline, and seabed. Unlike sediment dumping in shallow water, in deep water sediment particles inside the rock-fall pipe may be accelerated to dangerous speed at the outlet and thus require a sufficient distance between the rock-pipe outlet and the subsea pipeline so that sediments can be slowed down before making impact on the subsea pipeline. The purpose of the study is to find the optimal distance of the fall pipe outlet above the subsea pipeline with different suspension heights above seabed. The numerical model is first validated against available experimental data in terms of flow and sediment simulations. It is then used to investigate the detailed hydrodynamic characteristics and particle motions during sediment dumping in deep water, which can be divided into particle acceleration inside the rock-fall pipe and particle deceleration and diffusion out of the rock-fall pipe. While insufficient distance of the rock-fall pipe outlet above the subsea pipeline may lead to excessive impact force, too large distance may result in over-spreading of sediments and thus less efficiency of subsequent pipeline burial. Using a real project in the Liwan 3-1 region, China, as the case study, the numerical modeling results with prototype scale are used in the analysis to provide the optimal burying solution that uses the minimal amount of sediment to reach the protection criterion of the pipeline burial, when different pipeline suspensions above seabed are considered.

本文对海底管道埋置时通过落石管在深水中倾倒泥沙进行了数值研究。采用CFD-DEM耦合模型模拟沉积物、环境流、管道和海床之间的相互作用。与浅水倾倒泥沙不同，深水落石管道内的泥沙颗粒在出口可能被加速到危险的速度，因此需要在落石管道出口与海底管道之间有足够的距离，以使沉积物在撞击海底管道之前减速。研究的目的是寻找海底管道上方不同悬架高度下的落管出口的最优距离。数值模型首先在水流和泥沙模拟方面与现有实验数据进行了验证。利用该模型对深水排沙过程中颗粒运动和水动力特性进行了详细研究，其中颗粒运动可分为落岩管内的颗粒加速和落岩管外的颗粒减速扩散。落石管出口在海底管道上方的距离不够，可能导致冲击力过大，距离过大则可能导致沉积物过度扩散，从而降低后续管道埋置的效率。以中国荔湾3-1地区的实际工程为例，利用具有原型比例尺的数值模拟结果进行分析，在考虑不同海底管道悬浮物的情况下，给出了以最少泥沙量达到管道埋置保护标准的最优埋置方案。

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引用次数: 0

From hindcast to forecast: A statistical framework for real-time coastal circulation bulletins in the Gulf of Genoa 从后预报到预报：热那亚湾实时海岸环流公报的统计框架

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-11-29 DOI: 10.1016/j.apor.2024.104337

Mohammad Daliri , Francesco De Leo , Andrea Margarita Lira Loarca , Mattia Scovenna , Alessandro Stocchino , Marco Capello , Laura Cutroneo , Giovanni Besio

The increasing exploitation of coastal areas requires a detailed knowledge of environmental conditions that could be crucial for different applications, such as navigation safety and environmental protection. In this framework, this study introduces an offline forecast system for coastal circulation, being littoral currents among the main triggers of nearshore dynamics. The system utilizes clustering techniques for selecting relevant climatic scenarios based on historical metocean data, which are next used to simulate coastal circulation patterns through a robust modeling chain. The representative scenarios are then associated with meteocean forecast windows updated on a regular basis at the study area, i.e., the Gulf of Genoa in the Tyrrhenian Sea. Such operation takes advantage of tailored distance metrics, allowing to detect the closest scenario to the expected conditions, providing in turn real-time and refined predictions for coastal circulations. Such an offline approach ensures reliability, especially in coastal regions where accurate circulation forecasts are crucial for environmental management, marine navigation, and disaster preparedness.

对沿海地区日益增加的开发需要对环境条件有详细的了解，这对于航行安全和环境保护等不同的应用可能是至关重要的。在此框架下，本研究引入了沿海环流的离线预报系统，沿海环流是近岸动力学的主要触发因素之一。该系统利用聚类技术根据历史海洋气象数据选择相关的气候情景，然后通过一个强大的建模链来模拟沿海环流模式。然后将代表性情景与研究区域（即第勒尼安海的热那亚湾）定期更新的气象海洋预报窗口联系起来。这种作业利用了定制的距离指标，可以检测到最接近预期条件的场景，进而提供实时、精确的沿海环流预测。这种离线方法确保了可靠性，特别是在沿海地区，准确的环流预报对环境管理、海上航行和备灾至关重要。

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引用次数: 0

Real scale experiments on the wave-induced burial and mobilization of Unexploded Ordnance on the seafloor 海底未爆弹药在波浪作用下的掩埋和动员的真实规模实验

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-11-28 DOI: 10.1016/j.apor.2024.104342

Peter Menzel , Guido Wolters , Anja Drews

As a result of armed conflicts, huge amounts of Unexploded Ordnance devices (UXO) and Discarded Munition Material (DMM) are expected to be located on the seafloor, especially in coastal regions. During Offshore Construction, strategical site monitoring and systematic remediation activities, the behaviour of such objects in waves and currents is of huge interest as potential mobilization of objects after a survey or clearance activity could change the situational picture again. From findings and reports it often is assumed that UXO and DMM tend to migrate over the seafloor for long distances. Here, anthropogenic effects like fishing or dredging activities are underestimated. More scientific approaches clearly show that mobilization and migration of UXO over long distances does not occur. However, theoretical analysis remain theories until they are proven by experiments. For this reason, three large representative objects were investigated under real scale wave conditions in the Delta Flume of Deltares. The objects represent real scale models of UXO found in the North Sea as well as academically shaped objects. All objects as well as the Flume Tank were intensively instrumented to measure the full environmental conditions as well as the behaviour of the objects. The sediment represents typical sand as found in the North Sea and the seabed morphology and soil conditions were closely monitored during the experiments. The experiments support the theoretical models that predict burial but no mobilization also under extreme wave conditions.

由于武装冲突，预计将有大量未爆弹药装置（UXO）和废弃弹药材料（DMM）落在海底，特别是沿海地区。在海上施工、战略现场监测和系统修复活动中，这些物体在波浪和水流中的行为引起了人们的极大兴趣，因为在调查或清理活动后，这些物体的潜在动员可能会再次改变情况。从调查结果和报告来看，经常假定未爆弹药和DMM倾向于在海底长距离迁移。在这里，捕鱼或疏浚活动等人为影响被低估了。更科学的方法清楚地表明，远距离调动和移徙未爆炸弹药的情况并未发生。然而，理论分析仍然是理论，直到它们被实验证明。为此，在三角洲水槽的真实尺度波浪条件下，研究了三个具有代表性的大型物体。这些物体代表了在北海发现的未爆弹药的真实比例模型，以及学术形状的物体。所有的物体以及水槽都进行了密集的仪器测量，以测量完整的环境条件以及物体的行为。沉积物代表了北海典型的沙子，实验期间密切监测了海底形态和土壤条件。这些实验支持了在极端波浪条件下预测掩埋但不动员的理论模型。

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引用次数: 0