Jana Zaidan, Adrien Poupardin, Abdelkrim Bennabi, François Marin, Ahmed Benamar
Laboratory experiments are crucial for understanding scour around embedded structures. However, there is currently no standard and reliable instrumentation for monitoring the progression of this physical process in laboratory. In this paper, the capability of a novel 3D structural-light scanner technique to continuously measure the scour bed topography in uninterrupted flow is demonstrated. A suitable data processing procedure is developed to operate this device. Data processing is faster compared to other methods due to the automatic cloud reconstruction. This technique is rapid and allows for data acquisition with high vertical spatial accuracy. Flume tests are conducted on a circular pier founded in sand in clear water, as benchmark tests, to validate the effectiveness of this technique. The results observed with the scanner were coherent with those reported in the literature. Local scour initiation occurred near the sides of the pier. The maximum final scour depth measured was nearly equal to the pier diameter. This technique is considered non-intrusive under the tested hydraulic conditions and presents few limitations compared to other devices.
{"title":"Novel 3D Structural-Light Scanner Technique for Continuous Monitoring of Pier Scour in Laboratory","authors":"Jana Zaidan, Adrien Poupardin, Abdelkrim Bennabi, François Marin, Ahmed Benamar","doi":"10.3390/jmse12091566","DOIUrl":"https://doi.org/10.3390/jmse12091566","url":null,"abstract":"Laboratory experiments are crucial for understanding scour around embedded structures. However, there is currently no standard and reliable instrumentation for monitoring the progression of this physical process in laboratory. In this paper, the capability of a novel 3D structural-light scanner technique to continuously measure the scour bed topography in uninterrupted flow is demonstrated. A suitable data processing procedure is developed to operate this device. Data processing is faster compared to other methods due to the automatic cloud reconstruction. This technique is rapid and allows for data acquisition with high vertical spatial accuracy. Flume tests are conducted on a circular pier founded in sand in clear water, as benchmark tests, to validate the effectiveness of this technique. The results observed with the scanner were coherent with those reported in the literature. Local scour initiation occurred near the sides of the pier. The maximum final scour depth measured was nearly equal to the pier diameter. This technique is considered non-intrusive under the tested hydraulic conditions and presents few limitations compared to other devices.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"295 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Čedomir Benac, Neven Bočić, Lara Wacha, Lovro Maglić, Igor Ružić
Prvić Island (Kvarner area in the NE channel part of the Adriatic Sea) is a part of the Natura 2000 protected area network. A recent tombolo is located on the SW coast of Prvić Island, and much larger submerged tombolos are located on the shoal towards the south. Both phenomena are unique to the Croatian coast of the Adriatic Sea. The inland part of the tombolo was surveyed using an Unmanned Aerial Vehicle, and a 3D point cloud was created using Structure from Motion with Multi-View Stereo photogrammetry. The body of the talus breccia behind the tombolo has a triangular form. Large collapsed rocky blocks form the cape vertex. This cape is in a state of equilibrium in the present oceanographic conditions but might be eroded due to predicted rises in sea level. The submarine zone was explored using scuba-diving equipment and Remotely Operated Vehicles. A large triangle-shaped shoal consists of flysch. Parallel vertical sandstone layers that look like artificially built walls are more than a hundred metres long. The carbonate breccia is located at the end of the shallow zone. The conditions for the final formation of the submerged shoal were created during the sea level stagnation in the Holocene.
{"title":"The Recent and Submerged Tombolos—Unique Phenomena on the Adriatic Sea","authors":"Čedomir Benac, Neven Bočić, Lara Wacha, Lovro Maglić, Igor Ružić","doi":"10.3390/jmse12091575","DOIUrl":"https://doi.org/10.3390/jmse12091575","url":null,"abstract":"Prvić Island (Kvarner area in the NE channel part of the Adriatic Sea) is a part of the Natura 2000 protected area network. A recent tombolo is located on the SW coast of Prvić Island, and much larger submerged tombolos are located on the shoal towards the south. Both phenomena are unique to the Croatian coast of the Adriatic Sea. The inland part of the tombolo was surveyed using an Unmanned Aerial Vehicle, and a 3D point cloud was created using Structure from Motion with Multi-View Stereo photogrammetry. The body of the talus breccia behind the tombolo has a triangular form. Large collapsed rocky blocks form the cape vertex. This cape is in a state of equilibrium in the present oceanographic conditions but might be eroded due to predicted rises in sea level. The submarine zone was explored using scuba-diving equipment and Remotely Operated Vehicles. A large triangle-shaped shoal consists of flysch. Parallel vertical sandstone layers that look like artificially built walls are more than a hundred metres long. The carbonate breccia is located at the end of the shallow zone. The conditions for the final formation of the submerged shoal were created during the sea level stagnation in the Holocene.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"8 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To align with contemporary concepts of low-carbon and environmental protection, a new type of bucket-shaped permeable breakwater, based on the prototype of the bucket-based breakwater in Xuwei Port Area, Lianyungang, Jiangsu Province, China, was proposed. A three-dimensional numerical wave flume was constructed using the OpenFOAM platform and DXFlow (an open-source computational fluid dynamics toolbox based on OpenFOAM). The effectiveness of this numerical wave flume was validated through temporal and spatial verification, wave generation validation, and model testing. The study investigated the effects of bucket porosity, opening shapes, number of openings, and the positioning of these openings on the wave-dissipating performance under regular wave conditions. It analyzed the force characteristics near the openings. The results showed that within the relative wavelength range of L/D between 6.7 and 12.7, relative wave height H/d between 0.175 and 0.275, changes in wavelength had a limited impact on the wave-dissipating performance of the bucket-shaped permeable breakwater. The wave-dissipating performance was primarily related to the porosity, with the optimal overall wave-dissipating performance occurring at a bucket porosity of 12%. The shape and number of openings had a minimal relationship with performance. Additionally, the connecting walls of this type of breakwater experienced the most significant wave impact, suggesting that these areas should be reinforced in practical engineering applications.
{"title":"Numerical Investigation of the Hydrodynamic Characteristics of a Novel Bucket-Shaped Permeable Breakwater Using OpenFOAM","authors":"Anqi Yuan, Dongxu Wang, Yuejiao Jiang, Yifeng Wang, Jinsong Gui","doi":"10.3390/jmse12091574","DOIUrl":"https://doi.org/10.3390/jmse12091574","url":null,"abstract":"To align with contemporary concepts of low-carbon and environmental protection, a new type of bucket-shaped permeable breakwater, based on the prototype of the bucket-based breakwater in Xuwei Port Area, Lianyungang, Jiangsu Province, China, was proposed. A three-dimensional numerical wave flume was constructed using the OpenFOAM platform and DXFlow (an open-source computational fluid dynamics toolbox based on OpenFOAM). The effectiveness of this numerical wave flume was validated through temporal and spatial verification, wave generation validation, and model testing. The study investigated the effects of bucket porosity, opening shapes, number of openings, and the positioning of these openings on the wave-dissipating performance under regular wave conditions. It analyzed the force characteristics near the openings. The results showed that within the relative wavelength range of L/D between 6.7 and 12.7, relative wave height H/d between 0.175 and 0.275, changes in wavelength had a limited impact on the wave-dissipating performance of the bucket-shaped permeable breakwater. The wave-dissipating performance was primarily related to the porosity, with the optimal overall wave-dissipating performance occurring at a bucket porosity of 12%. The shape and number of openings had a minimal relationship with performance. Additionally, the connecting walls of this type of breakwater experienced the most significant wave impact, suggesting that these areas should be reinforced in practical engineering applications.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"111 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jin Zhang, Shuyin Deng, Yulseong Kim, Xuebin Zheng
In this study, the static and dynamic performance efficiencies of container terminals are analyzed and compared for the main container terminals in China and Korea. The static performance efficiency is calculated using the Super-SBM model based on slack variables at the micro-level. An analysis on the dynamic performance efficiency is conducted with the Malmquist index method. The factors of scale and technology of container terminals are mainly taken into account to explore the performance efficient improvement path of container ports. We obtained the following conclusions: (1) The container terminals in Korea show a similar performance efficiency level to the terminals in China, and their performance efficiency is an overall upward trend over the past five years. (2) The main reason for inefficiency in the container terminals in China and Korea is predominantly scale inefficiency. (3) Boosting the automation degree does not have a completely positive impact on the efficiency of the terminal. (4) In 2019–2023, the technical progress index of all container terminals in China and Korea showed a decreasing trend, leading to performance inefficiency of the container terminals.
{"title":"A Comparative Analysis of Performance Efficiency for the Container Terminals in China and Korea","authors":"Jin Zhang, Shuyin Deng, Yulseong Kim, Xuebin Zheng","doi":"10.3390/jmse12091568","DOIUrl":"https://doi.org/10.3390/jmse12091568","url":null,"abstract":"In this study, the static and dynamic performance efficiencies of container terminals are analyzed and compared for the main container terminals in China and Korea. The static performance efficiency is calculated using the Super-SBM model based on slack variables at the micro-level. An analysis on the dynamic performance efficiency is conducted with the Malmquist index method. The factors of scale and technology of container terminals are mainly taken into account to explore the performance efficient improvement path of container ports. We obtained the following conclusions: (1) The container terminals in Korea show a similar performance efficiency level to the terminals in China, and their performance efficiency is an overall upward trend over the past five years. (2) The main reason for inefficiency in the container terminals in China and Korea is predominantly scale inefficiency. (3) Boosting the automation degree does not have a completely positive impact on the efficiency of the terminal. (4) In 2019–2023, the technical progress index of all container terminals in China and Korea showed a decreasing trend, leading to performance inefficiency of the container terminals.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"63 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Yangtze River’s substantial variation in water depth and current speeds means that inland ships face diverse operational conditions within a single voyage. This paper discusses the adoption of controllable-pitch propellers, which adjust their pitch to adapt to varying navigational environments, thereby optimizing energy efficiency. We developed an optimization framework to determine the ideal pitch angle and rotation speed (RPM) under different sailing conditions. The energy performance model for inland ships was enhanced to account for the open-water efficiency of CPPs across various pitch angles and RPMs, considering the impacts of current and shallow water, among other factors. The optimization approach was refined by incorporating an improved genetic algorithm with an annealing algorithm to enhance the initial population, applying the K-means clustering algorithm for population segmentation, and using multi-parent crossover from diverse clusters. The efficacy of the optimization method for CPP operations was validated by analyzing three operational scenarios of a Yangtze sailing ship. Additionally, key components of the ship performance model were calibrated through experimental tests, demonstrating an anticipated fuel consumption reduction of approximately 5% compared to conventional fixed-pitch propellers.
{"title":"Optimization of Controllable-Pitch Propeller Operations for Yangtze River Sailing Ships","authors":"Wuliu Tian, Xiao Lang, Chi Zhang, Songyin Yan, Bing Li, Shuo Zang","doi":"10.3390/jmse12091579","DOIUrl":"https://doi.org/10.3390/jmse12091579","url":null,"abstract":"The Yangtze River’s substantial variation in water depth and current speeds means that inland ships face diverse operational conditions within a single voyage. This paper discusses the adoption of controllable-pitch propellers, which adjust their pitch to adapt to varying navigational environments, thereby optimizing energy efficiency. We developed an optimization framework to determine the ideal pitch angle and rotation speed (RPM) under different sailing conditions. The energy performance model for inland ships was enhanced to account for the open-water efficiency of CPPs across various pitch angles and RPMs, considering the impacts of current and shallow water, among other factors. The optimization approach was refined by incorporating an improved genetic algorithm with an annealing algorithm to enhance the initial population, applying the K-means clustering algorithm for population segmentation, and using multi-parent crossover from diverse clusters. The efficacy of the optimization method for CPP operations was validated by analyzing three operational scenarios of a Yangtze sailing ship. Additionally, key components of the ship performance model were calibrated through experimental tests, demonstrating an anticipated fuel consumption reduction of approximately 5% compared to conventional fixed-pitch propellers.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"8 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuqing Yang, Jie Xu, Lanting Ji, Qingquan Sun, Muzi Zhang, Shanshan Zhao, Chi Wu
Ocean salinity plays an important role in oceanographic research as one of the fundamental parameters. An optical salinometer based on the Michelson interferometer (MI) suitable for in situ measurement in deep-sea environments is proposed in this work, and it features real-time calibration and multichannel multiplexing using the frequency modulated continuous wave (FMCW) technique. The symmetrical sapphire structure used to withstand deep-sea pressure can not only achieve automatic temperature compensation, but also counteract the changes in optical path length under deep-sea pressure. A model formula suitable for optical salinity demodulation is proposed through the nonlinear least squares fitting method. In vertical profile testing, the optical salinometer demonstrated remarkable tracking performance, achieving an error of less than 0.001 psu. The sensor displays a stable salinity demodulation error within ±0.002 psu during a three-month long-term test at a depth of 4000 m. High stability and resolution make this optical salinometer have broad development prospects in ocean observation.
{"title":"In Situ Measurement of Deep-Sea Salinity Using Optical Salinometer Based on Michelson Interferometer","authors":"Shuqing Yang, Jie Xu, Lanting Ji, Qingquan Sun, Muzi Zhang, Shanshan Zhao, Chi Wu","doi":"10.3390/jmse12091569","DOIUrl":"https://doi.org/10.3390/jmse12091569","url":null,"abstract":"Ocean salinity plays an important role in oceanographic research as one of the fundamental parameters. An optical salinometer based on the Michelson interferometer (MI) suitable for in situ measurement in deep-sea environments is proposed in this work, and it features real-time calibration and multichannel multiplexing using the frequency modulated continuous wave (FMCW) technique. The symmetrical sapphire structure used to withstand deep-sea pressure can not only achieve automatic temperature compensation, but also counteract the changes in optical path length under deep-sea pressure. A model formula suitable for optical salinity demodulation is proposed through the nonlinear least squares fitting method. In vertical profile testing, the optical salinometer demonstrated remarkable tracking performance, achieving an error of less than 0.001 psu. The sensor displays a stable salinity demodulation error within ±0.002 psu during a three-month long-term test at a depth of 4000 m. High stability and resolution make this optical salinometer have broad development prospects in ocean observation.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"7 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
José J. Alonso del Rosario, Elizabeth Blázquez Gómez, Juan Manuel Vidal Pérez, Faustino Martín Rey, Esther L. Silva-Ramírez
The ATLAZUL project is an Interreg effort among 18 partners from Spain and Portugal along the Atlantic Iberian coasts. One of its objectives is the development of new methods and data processing for oceanic information to produce useful products for private and public stakeholders. This study proposes a new insight on the sea surface dynamic of the ATLAZUL area based on almost two years of multiscale high resolution sea surface temperature imagery. The use of techniques such as the Karhunen–Loève transform (Empirical Orthogonal Function) and the Maximum Entropy Spectral Analysis were applied to study long- and short-term features in the sea surface temperature imagery. Mathematical Morphology and the Geometrical Theory of Measure are utilized to compute the Medial Axis Transform and the Hausdorff dimension. The results can be summarized as follows: (i) the tow upwelling areas are identified along the Galician–Portugal coast as indicated in the second and third modes of KLT/EOF analysis, and they are partially affected by wind; (ii) the tow warm water outflows from the Bay of Cádiz to the Gulf of Cádiz are identified as the second and third modes of KLT/EOF analysis, which are also influenced by wind; (iii) the skeletons of the surface signature of the upwelling and of the warmer water outflow, along with their fractal dimensions, indicate a chaotic pattern of spatial distribution and (iv) the harmonic prediction model should be combined with the wind prediction.
{"title":"A New Insight on the Upwelling along the Atlantic Iberian Coasts and Warm Water Outflow in the Gulf of Cadiz from Multiscale Ultrahigh Resolution Sea Surface Temperature Imagery","authors":"José J. Alonso del Rosario, Elizabeth Blázquez Gómez, Juan Manuel Vidal Pérez, Faustino Martín Rey, Esther L. Silva-Ramírez","doi":"10.3390/jmse12091580","DOIUrl":"https://doi.org/10.3390/jmse12091580","url":null,"abstract":"The ATLAZUL project is an Interreg effort among 18 partners from Spain and Portugal along the Atlantic Iberian coasts. One of its objectives is the development of new methods and data processing for oceanic information to produce useful products for private and public stakeholders. This study proposes a new insight on the sea surface dynamic of the ATLAZUL area based on almost two years of multiscale high resolution sea surface temperature imagery. The use of techniques such as the Karhunen–Loève transform (Empirical Orthogonal Function) and the Maximum Entropy Spectral Analysis were applied to study long- and short-term features in the sea surface temperature imagery. Mathematical Morphology and the Geometrical Theory of Measure are utilized to compute the Medial Axis Transform and the Hausdorff dimension. The results can be summarized as follows: (i) the tow upwelling areas are identified along the Galician–Portugal coast as indicated in the second and third modes of KLT/EOF analysis, and they are partially affected by wind; (ii) the tow warm water outflows from the Bay of Cádiz to the Gulf of Cádiz are identified as the second and third modes of KLT/EOF analysis, which are also influenced by wind; (iii) the skeletons of the surface signature of the upwelling and of the warmer water outflow, along with their fractal dimensions, indicate a chaotic pattern of spatial distribution and (iv) the harmonic prediction model should be combined with the wind prediction.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"45 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhifan Zhang, Bo Jiang, Longkan Wang, Shengren Wei, Tao Li, Guiyong Zhang, Zhi Zong
When undertaking long-distance missions at sea, vessels aim to achieve an extended operational range through drag reduction and energy efficiency, while enhanced wave resilience also provides substantial benefits. In this work, the Delft-372 catamaran is utilized to investigate the feasibility of drag reduction and roll mitigation for catamaran formation sailing in waves, analyzing the effects of three different formation configurations and varying spacings. The overset grid method was employed to simulate vessel motions, while the Volume of Fluid (VOF) method captured the free surface. First, the numerical results of the catamaran’s resistance, pitch, and heave motion amplitudes under different wave conditions were compared with experimental data to verify the accuracy of the CFD numerical method, and a grid convergence analysis was performed. Next, numerical models of the Delft-372 catamaran were constructed in parallel, tandem, and lateral formations under wave conditions. The results of the single-ship simulation were employed as a benchmark to analyze the impact of different formation configurations and varying lateral and longitudinal spacings on the resistance, pitch, and heave motions of the catamarans. The study also examined the effects of wave interference between vessels and the combined influence of external waves on individual and overall hydrodynamic performance. Results indicated that the tandem formation outperformed the parallel and lateral formations, with optimal performance observed at the longitudinal distance of 1 LPP. Generally, during navigation, the follower catamaran should ideally be positioned in the trough of the stern wave of the leader catamaran.
{"title":"Hydrodynamic Analysis of Different Formation Configurations of Catamaran in Regular Head Waves","authors":"Zhifan Zhang, Bo Jiang, Longkan Wang, Shengren Wei, Tao Li, Guiyong Zhang, Zhi Zong","doi":"10.3390/jmse12091577","DOIUrl":"https://doi.org/10.3390/jmse12091577","url":null,"abstract":"When undertaking long-distance missions at sea, vessels aim to achieve an extended operational range through drag reduction and energy efficiency, while enhanced wave resilience also provides substantial benefits. In this work, the Delft-372 catamaran is utilized to investigate the feasibility of drag reduction and roll mitigation for catamaran formation sailing in waves, analyzing the effects of three different formation configurations and varying spacings. The overset grid method was employed to simulate vessel motions, while the Volume of Fluid (VOF) method captured the free surface. First, the numerical results of the catamaran’s resistance, pitch, and heave motion amplitudes under different wave conditions were compared with experimental data to verify the accuracy of the CFD numerical method, and a grid convergence analysis was performed. Next, numerical models of the Delft-372 catamaran were constructed in parallel, tandem, and lateral formations under wave conditions. The results of the single-ship simulation were employed as a benchmark to analyze the impact of different formation configurations and varying lateral and longitudinal spacings on the resistance, pitch, and heave motions of the catamarans. The study also examined the effects of wave interference between vessels and the combined influence of external waves on individual and overall hydrodynamic performance. Results indicated that the tandem formation outperformed the parallel and lateral formations, with optimal performance observed at the longitudinal distance of 1 LPP. Generally, during navigation, the follower catamaran should ideally be positioned in the trough of the stern wave of the leader catamaran.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"12 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sheraz Aslam, Michalis P. Michaelides, Herodotos Herodotou
The significant increase in international seaborne trade volumes over the last several years is pushing port operators to improve the efficiency of terminal processes and reduce vessel turnaround time. Toward this direction, this study investigates and solves the combined berth allocation problem (BAP) and quay crane allocation problem (QCAP) in a multi-quay (MQ) setting using computational intelligence (CI) approaches. First, the study develops a mathematical model representing a real port environment and then adapts the cuckoo search algorithm (CSA) for the first time in this setup. The CSA is inspired by nature by following the basic rules of breeding parasitism of some cuckoo species that lay eggs in other birds’ nests. For comparison purposes, we implement two baseline approaches, first come first serve and exact MILP, and two CI approaches, particle swarm optimization (PSO) and genetic algorithm (GA), that are typically used to solve such complex or NP-hard problems. Performance assessment is carried out via a comprehensive series of experiments using real-world data. Experimental findings show that the MILP method can address the problems only when a small dataset is employed. In contrast, the newly adapted CSA can solve larger instances of MQ BAP and QCAP within significantly reduced computation times.
{"title":"Optimizing Multi-Quay Combined Berth and Quay Crane Allocation Using Computational Intelligence","authors":"Sheraz Aslam, Michalis P. Michaelides, Herodotos Herodotou","doi":"10.3390/jmse12091567","DOIUrl":"https://doi.org/10.3390/jmse12091567","url":null,"abstract":"The significant increase in international seaborne trade volumes over the last several years is pushing port operators to improve the efficiency of terminal processes and reduce vessel turnaround time. Toward this direction, this study investigates and solves the combined berth allocation problem (BAP) and quay crane allocation problem (QCAP) in a multi-quay (MQ) setting using computational intelligence (CI) approaches. First, the study develops a mathematical model representing a real port environment and then adapts the cuckoo search algorithm (CSA) for the first time in this setup. The CSA is inspired by nature by following the basic rules of breeding parasitism of some cuckoo species that lay eggs in other birds’ nests. For comparison purposes, we implement two baseline approaches, first come first serve and exact MILP, and two CI approaches, particle swarm optimization (PSO) and genetic algorithm (GA), that are typically used to solve such complex or NP-hard problems. Performance assessment is carried out via a comprehensive series of experiments using real-world data. Experimental findings show that the MILP method can address the problems only when a small dataset is employed. In contrast, the newly adapted CSA can solve larger instances of MQ BAP and QCAP within significantly reduced computation times.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"8 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Near-inertial waves (NIWs), a special form of internal waves with a frequency close to the local Coriolis frequency, are ubiquitous in the ocean. NIWs play a crucial role in ocean mixing, influencing energy transport, climate change, and biogeochemistry. This manuscript briefly reviews the generation and propagation of NIWS in the oceans. NIWs are primarily generated at the surface by wind forcing or through the water column by nonlinear wave-wave interaction. Especially at critical latitudes where the tidal frequency is equal to twice the local inertial frequency, NIWs can be generated by a specific subclass of triadic resonance, parametric subharmonic instability (PSI). There are also other mechanisms, including lee wave and spontaneous generation. NIWs can propagate horizontally for hundreds of kilometers from their generating region and radiate energy far away from their origin. NIWs also penetrate deep into the ocean, affecting nutrient and oxygen redistribution through altering mixing. NIW propagation is influenced by factors such as mesoscale eddies, background flow, and topography. This review also discussed some recent observational evidence of interactions between NIWs from different origins, suggesting a complicated nonlinear interaction and energy cascading. Despite the long research history, there are still many areas of NIWs that are not well defined.
{"title":"The Generation and Propagation of Wind- and Tide-Induced Near-Inertial Waves in the Ocean","authors":"Yang Li, Zhao Xu, Xianqing Lv","doi":"10.3390/jmse12091565","DOIUrl":"https://doi.org/10.3390/jmse12091565","url":null,"abstract":"Near-inertial waves (NIWs), a special form of internal waves with a frequency close to the local Coriolis frequency, are ubiquitous in the ocean. NIWs play a crucial role in ocean mixing, influencing energy transport, climate change, and biogeochemistry. This manuscript briefly reviews the generation and propagation of NIWS in the oceans. NIWs are primarily generated at the surface by wind forcing or through the water column by nonlinear wave-wave interaction. Especially at critical latitudes where the tidal frequency is equal to twice the local inertial frequency, NIWs can be generated by a specific subclass of triadic resonance, parametric subharmonic instability (PSI). There are also other mechanisms, including lee wave and spontaneous generation. NIWs can propagate horizontally for hundreds of kilometers from their generating region and radiate energy far away from their origin. NIWs also penetrate deep into the ocean, affecting nutrient and oxygen redistribution through altering mixing. NIW propagation is influenced by factors such as mesoscale eddies, background flow, and topography. This review also discussed some recent observational evidence of interactions between NIWs from different origins, suggesting a complicated nonlinear interaction and energy cascading. Despite the long research history, there are still many areas of NIWs that are not well defined.","PeriodicalId":16168,"journal":{"name":"Journal of Marine Science and Engineering","volume":"31 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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