Applied Ocean Research最新文献

{"title":"Reconstructing trajectories and extracting shipping routes between ports based on AIS data","authors":"Zhaojin Yan ,&nbsp;Guanghao Yang ,&nbsp;Rong He ,&nbsp;Kai Shi ,&nbsp;Hui Yang","doi":"10.1016/j.apor.2025.104709","DOIUrl":"10.1016/j.apor.2025.104709","url":null,"abstract":"<div><div>The reliability of Automatic Identification System (AIS) data is often compromised due to equipment errors, human errors, and high ship density, leading to missing information in the raw data. This unreliability can hinder maritime traffic research and cause misjudgements by maritime authorities, potentially resulting in unnecessary losses. Therefore, reconstructing missing AIS data is beneficial for traffic management and safety monitoring by maritime administration. This study proposes a ship trajectory reconstruction method based on AIS data, which reconstructs missing trajectory points using the course over ground (COG) and the positions of existing AIS data. Additionally, a method for extracting inter-port shipping routes and calculating their spatio-temporal features is introduced. By employing adaptive BIRCH (Balanced Iterative Reducing and Clustering using Hierarchies) clustering and trajectory resampling, optimal inter-port shipping routes are identified, and features such as average navigation time, speed, and draught are extracted. The proposed method was tested using real AIS data from the Bohai Sea area in January 2017. Results demonstrated the effectiveness of the method in reconstructing ship trajectories and extracting optimal shipping routes along with their spatio-temporal features. Comparative experiments with three popular trajectory reconstruction methods-Linear interpolation, Cubic interpolation, and B-spline interpolation-showed the superiority of the proposed method. This study provides new approaches for ship trajectory reconstruction and inter-port shipping route extraction based on AIS data. The results of this study are expected to provide more accurate and reliable data support for maritime management departments, enhance route planning, traffic efficiency, and risk warning capabilities, and offer significant practical value.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104709"},"PeriodicalIF":4.3,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144697006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the performance of a repurposed oil and gas platform for offshore wind energy generation","authors":"Ding Peng Liu ,&nbsp;Taemin Heo ,&nbsp;Lance Manuel","doi":"10.1016/j.apor.2025.104696","DOIUrl":"10.1016/j.apor.2025.104696","url":null,"abstract":"<div><div>In an ongoing offshore energy transition period underway, fossil fuel extraction and associated carbon emission are expected to gradually be replaced by cleaner wind and wave energy generation alternatives. Many oil and gas platforms have reached or are nearing their end of useful life. In an earlier study, we addressed the feasibility of sustainable reuse of such platforms for wind energy generation instead of dismantling them. Such a re-purposing was evaluated using a fatigue reliability-based framework, along with cost considerations. In the present study, we further examine short-term fatigue across different environmental conditions using OpenFAST time-domain simulations. Axial stresses at four different locations of the platform during the repurposed phase (with a wind turbine) platform are simulated for nine representative sea states, with a focus on fatigue damage estimates in these sea states. Additionally, this work is focusing on assessing the feasibility of repurposed platform under extreme sea states. From our studies, we find that a location low in the leg of the platform is most critical when evaluating fatigue as well as ultimate limit states. Sea states associated with high wind speeds contribute to greater fatigue damage because of fluctuations in the wind loading and resonance response characteristics. These insights will be valuable for structural retrofit strategies and reuse planning.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104696"},"PeriodicalIF":4.3,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visualization of velocity and kinetic energy variations at the air-water interface during wave breaking","authors":"Ruey-Syan Shih ,&nbsp;Chi-Yu Li ,&nbsp;Ching-Tang Huang","doi":"10.1016/j.apor.2025.104704","DOIUrl":"10.1016/j.apor.2025.104704","url":null,"abstract":"<div><div>This study examines turbulent, multiphase flow dynamics in the gas phase induced by wave breaking in coastal environments, focusing on void ratio quantification and its effects on flow characteristics, kinetic energy, and density-related energy transfer. The entrainment of air, bubble formation, and high-velocity gradients from breaking waves pose challenges for conventional flow measurements, while transient air–water interactions further complicate the analysis of gas-phase dynamics. To address these complexities, Particle Image Velocimetry (PIV) is employed to quantify gas-phase phenomena and velocity distributions under three distinct wave-breaking conditions relevant to offshore engineering. PIV enables detailed analysis of velocity fields at the water–air interface, capturing variations in kinetic energy and momentum in the surrounding air phase. Additionally, the study compares water and gas momentum distributions and investigates kinetic energy variations induced by wave impacts. The evolution of water–gas velocity fields is also analyzed across different wave-breaking types over an impermeable sloped bottom, providing insights into air–water interaction mechanisms in coastal hydrodynamics.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104704"},"PeriodicalIF":4.3,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global movement and structural deformation prediction of a floating multi-purpose offshore platform: an engineering approach in the context of the design of the platform automation and control system","authors":"Fabrizio Lagasco ,&nbsp;Ambra Zuccarino ,&nbsp;Alessandro Largo ,&nbsp;Giovanni Gambaro ,&nbsp;Carlo Ruzzo ,&nbsp;Anita Santoro ,&nbsp;Felice Arena","doi":"10.1016/j.apor.2025.104701","DOIUrl":"10.1016/j.apor.2025.104701","url":null,"abstract":"<div><div>Integrating renewable energy sources with aquaculture systems on floating Multi-purpose Offshore Installations (MOI) offers an innovative and sustainable solution to harness the vast potential of the ocean. Despite several designs have been attempted, the difficulties to prove at harsh environment in real scale remain the main challenge. Whilst the industrial target of the proposed platform design is to enable automated aquaculture production supported by wind, wave and solar energy harvesting technologies in a profitable way benefiting of the available energy resources, as well as of the healthier conditions for fish farming, the technical challenge is focused on the capacity to withstand the harsh environment of the deep waters installation and to guarantee structural integrity during the in-service lifetime. Test before Invest principle requires studying these installations through increasing steps, experiencing prototypes at various scales to investigate about the installation dynamics and capacity to resist the loading conditions over the operative life. The full-scale design, among others, has to consider how to secure insurance coverage for the asset over its operational lifetime, and how to support decisions on extending the asset’s service life, particularly following the replacement of long-lead technological components at the 25-year mark. Designing robust and efficient control and monitoring system based on key structural and deformation data measurements through the operative life may support these achievements, even if practical applications are not available yet. In the context of the design of an innovative MOI developed within “The Blue Growth Farm” (BGF) European Commission (EC) funded H2020 project, the challenge to study and implement a model to predict the floating platform movement and deformation under in-service loading has emerged to be key to define an efficient automation and control system for the installation. This paper describes the engineering process adopted to achieve this objective, considering the novelty of the platform concept and the lack of similar industrial MOI automation and control experience. The proposed methodology focuses on the use of machine learning (ML) techniques and its validation process by exploiting data acquired during an experimental campaign at sea developed on a scaled version (prototype) of the proposed infrastructure. Tests carried out aimed at capturing the complex structure dynamics through data recorded in a wide experimental campaign between May and September 2021 at the Natural Ocean Engineering Laboratory (NOEL) of Reggio Calabria (Italy).</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104701"},"PeriodicalIF":4.3,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surrogate hydrodynamic modelling for wave energy system control co-design","authors":"Simon Leboucher ,&nbsp;Colm J. Fitzgerald ,&nbsp;John V. Ringwood","doi":"10.1016/j.apor.2025.104679","DOIUrl":"10.1016/j.apor.2025.104679","url":null,"abstract":"<div><div>Optimisation and control co-design, for wave energy systems, is receiving increased focus, in the drive to design commercially viable wave energy systems. A consistent bottleneck in wave energy converter (WEC) system optimisation is the need to iteratively calculate hydrodynamic forces, which is computationally time-consuming. One solution, to improve the computational efficiency of WEC optimisation loops, is through the use of <em>surrogate</em> models, which are computationally efficient approximations of the fundamental calculations provided by linear potential-flow boundary-element solvers. Surrogate models offer a computationally efficient framework for conducting iterative design optimisation provided sampling of the search space, when collating training data at the pre-computation stage, is well designed. Surrogate models can be used both to evaluate hydrodynamic response parameters and to calculate objective function values (e.g., captured energy or cost of energy), within design optimisation loops. This study explores both options and examines the computational time/fidelity trade-off involved in the use of surrogate models for WEC geometry optimisation.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104679"},"PeriodicalIF":4.3,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reinforcement learning approaches in the motion systems of autonomous underwater vehicles","authors":"Ting Yu ,&nbsp;Qi Zhang ,&nbsp;Tiejun Liu","doi":"10.1016/j.apor.2025.104682","DOIUrl":"10.1016/j.apor.2025.104682","url":null,"abstract":"<div><div>Autonomous underwater vehicles (AUVs) have been receiving increasing attention due to the significant role in the exploration of ocean resources. The complex underwater disturbances and highly coupled models pose significant challenges to the design of motion systems (MS) of AUVs. As a result, reinforcement learning (RL) methods that can develop robust control strategies without relying heavily on models have become a research focus of AUVs. However, the task space division for motion systems based on RL remains unclear, and systematic design approaches or summaries are lacking in this field. In this paper, we review RL-based approaches in the motion systems of AUVs in detail. Specifically, the task space of the motion systems of AUVs is classified into three categories: motion control, motion planning, and multi-AUV motion. For each task space, a targeted motion architecture is introduced along with a review of the latest advancements. In terms of motion control, auxiliary and direct motion control approaches are introduced herein. Regarding motion planning, path-oriented, state-oriented, and end-to-end approaches are discussed. For multi-AUV motion, formation motion and motion task coordination are summarized. Finally, challenges of applying reinforcement learning approaches to the motion systems of AUVs are outlined and potential future breakthroughs in this field are anticipated herein. This paper provides a detailed review of RL-based methods in motion systems of AUVs, summarizing the design architecture and network model based on RL approaches for motion systems. This will offer valuable design solutions and insights for practitioners and beginners, further promoting the application of RL methods to address complex motion system design challenges of AUVs.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104682"},"PeriodicalIF":4.3,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-chamber cylindrical OWC: analytical model and numerical results","authors":"Antonino Simone Spanò ,&nbsp;Giovanni Malara ,&nbsp;Felice Arena","doi":"10.1016/j.apor.2025.104695","DOIUrl":"10.1016/j.apor.2025.104695","url":null,"abstract":"<div><div>Wave energy has the potential to play a crucial role in the ongoing energy transition towards the exploitation of renewable energy sources. Among the wave energy converters, Oscillating Water Column (OWC) is recognized to be one of the most promising technologies. Despite the amount of research conducted on those devices, there is no consensus on the optimal OWC configuration. In this context, circular OWCs emerged as an attractive option as it is a configuration unaffected by the direction of the incoming waves. Recently, research focused on devices equipped with multiple chambers in order to increase the overall device efficiency via the introduction of concentric chambers. This paper studies a multi-chamber concept arising from the partition of a cylindrical single chamber OWC into multiple chambers spanning a reduced inner angular width. Within the linearized potential flow theory, throughout the eigenfunction expansion matching method, and considering a linear power take off, a semi-analytical solution is obtained. Next, numerical results pertaining to the cases of a circular OWC comprising two and three chambers, spanning the whole inner sector, are discussed. The numerical analysis shows that the use of multiple chambers having a reduced angular width increases the overall energy-wise performance of the system with respect to the case of a single chamber OWC.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104695"},"PeriodicalIF":4.3,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An experimental study of weakly nonlinear waves atop a vertically sheared current","authors":"Zirui Xin ,&nbsp;Xin Li ,&nbsp;Jun Li ,&nbsp;Samuel Draycott ,&nbsp;Yan Li","doi":"10.1016/j.apor.2025.104680","DOIUrl":"10.1016/j.apor.2025.104680","url":null,"abstract":"<div><div>We carry out a laboratory study of weakly nonlinear waves atop a following, vertically sheared current, relevant for a wide range of coastal and ocean locations. The experimental observations are compared with existing theories for the shear-current modified dispersion relation and amplitudes of second-harmonic waves, where a good agreement has been shown. Both the experiments and theoretical calculations show that the findings for wave groups and regular waves are consistently affected by the presence of the following current. For regular (carrier) waves with a fixed absolute frequency, the additional presence of the following current is found to decrease the amplitude of the second-harmonic waves when the linear amplitude is fixed, yet increase the second-harmonic waves when the steepness is fixed owing to the additional shear-current modified effects on the dispersion relation of linear waves. These nuanced and apparently contrasting findings address the significance of resolving the combined wave–current field effectively to ensure a correct interpretation of wave properties in field measurements.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104680"},"PeriodicalIF":4.3,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The coupling effect of current, wave and platform movement on the dynamic characteristics of marine risers with different elastic modulus and constraint number","authors":"Keshun Ma ,&nbsp;Chunguang Wang ,&nbsp;Wentao He ,&nbsp;Lin Zhang ,&nbsp;Run Zheng ,&nbsp;Chiemela Victor Amaechi ,&nbsp;Zhenyang Zhang","doi":"10.1016/j.apor.2025.104694","DOIUrl":"10.1016/j.apor.2025.104694","url":null,"abstract":"<div><div>An experimental study was conducted to investigate the dynamic response of production risers under the coupling effect of current, wave and platform movement. Seven experimental parameters were considered, i.e., elastic modulus, constraint number, flow velocity, wave height, wave period, static movement of platform and dynamic movement of platform. Based on these parameters, 32 test conditions were designed and conducted. By employing a multiple nonlinear regression model and biased estimation regression method, the influence of coupling effect and the impact of various parameters on the dynamic response of the risers were obtained. The results showed that increasing the number of coupled parameters enhanced the model’s reliability; and when three parameters were coupled, an acceptable accuracy could be achieved. It’s also found that the sequence of importance for the vibration of the riser in the in-flow direction was: static displacement &gt; elastic modulus &gt; constraint number &gt; wave period &gt; wave height &gt; flow velocity &gt; dynamic displacement; while in the cross-flow direction was: elastic modulus &gt; flow velocity &gt; static displacement &gt; wave period &gt; wave height &gt; constraint number &gt; dynamic displacement.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104694"},"PeriodicalIF":4.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of settling velocity for cuboidal microplastic","authors":"Seung-Jae Kwon ,&nbsp;Young-Gyu Park ,&nbsp;Le Duc Quyen ,&nbsp;In-Cheol Lee ,&nbsp;Jun Myoung Choi","doi":"10.1016/j.apor.2025.104693","DOIUrl":"10.1016/j.apor.2025.104693","url":null,"abstract":"<div><div>Accurate settling velocity estimation is crucial for modeling microplastic distribution in the ocean, and this estimation can be achieved using nondimensional correlations. This study experimentally investigates the settling velocity of irregularly shaped microplastics and proposes new empirical correlations for drag coefficient and dimensionless settling velocity. Microplastic shape and size were standardized using 3D printing: 150 cuboidal microplastics with minimum dimensions of 0.2 mm and aspect ratios ranging from fiber-like (1:1:10) to plate-like (10:10:1) were fabricated. Experiments were conducted in water and a water-glycerol mixture, spanning a Reynolds number range of 0.03 to 200. New empirical correlations for drag coefficient and dimensionless settling velocity were developed using equivalent and longest length scales, incorporating various shape factors. The root mean square error in predicted settling velocity using these correlations averaged 11.7 %. Comparisons with existing drag models demonstrate the improved accuracy of our proposed correlations, providing more reliable methods for predicting microplastic behavior in diverse marine environments, from coastal regions to the open ocean.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"161 ","pages":"Article 104693"},"PeriodicalIF":4.3,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}