E. Kiosidou, Dimitrios E. Liarokapis, Georgios D. Tzabiras, Dimitrios I. Pantelis
In this work, an experimental investigation of the hydrodynamic resistance of a flat plate painted with newly developed marine antifouling paints of polyurethane (PU) and silicone (Si) formulations was performed. In total, six different paint systems of Si, PU, and acrylic formulations were applied, both experimental and commercial. The total resistance of each painted condition of the plate was measured through towing tank tests for the range of 0.75–2.5m/sec, with a step of 0.25m/sec. The Si and PU formulations exhibited similar hydrodynamic behavior, fluctuating around the smooth condition, whereas the acrylic system exhibited the highest resistance increase of all. The roughness function calculation was based on Ra and the correlation with the Colebrook roughness function was generally limited for most systems. Extrapolation to ship scale revealed that no significant drag differences are expected in the as-painted condition among the different paint system types.
在这项工作中，对使用新开发的聚氨酯（PU）和硅酮（Si）配方船舶防污漆的平板的流体阻力进行了实验研究。总共使用了六种不同的硅酮、聚氨酯和丙烯酸涂料体系，既有实验性的，也有商业性的。在 0.75-2.5 米/秒的范围内，以 0.25 米/秒为一个步长，通过拖曳槽试验测量了板上每种涂漆状态的总阻力。硅配方和聚氨酯配方表现出相似的流体力学行为，在光滑状态附近波动，而丙烯酸配方的阻力增幅最大。粗糙度函数的计算以 Ra 为基础，对于大多数系统而言，与 Colebrook 粗糙度函数的相关性普遍有限。对船舶尺度的推断表明，不同类型的涂料系统在涂漆状态下预计不会出现明显的阻力差异。
{"title":"Experimental Investigation of Paint Roughness on the Resistance of a Flat Plate","authors":"E. Kiosidou, Dimitrios E. Liarokapis, Georgios D. Tzabiras, Dimitrios I. Pantelis","doi":"10.5957/josr.01230003","DOIUrl":"https://doi.org/10.5957/josr.01230003","url":null,"abstract":"In this work, an experimental investigation of the hydrodynamic resistance of a flat plate painted with newly developed marine antifouling paints of polyurethane (PU) and silicone (Si) formulations was performed. In total, six different paint systems of Si, PU, and acrylic formulations were applied, both experimental and commercial. The total resistance of each painted condition of the plate was measured through towing tank tests for the range of 0.75–2.5m/sec, with a step of 0.25m/sec. The Si and PU formulations exhibited similar hydrodynamic behavior, fluctuating around the smooth condition, whereas the acrylic system exhibited the highest resistance increase of all. The roughness function calculation was based on Ra and the correlation with the Colebrook roughness function was generally limited for most systems. Extrapolation to ship scale revealed that no significant drag differences are expected in the as-painted condition among the different paint system types.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":"67 17","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138957131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To study the geographical distribution characteristics of maritime traffic risks, statistical representations of potential accident scenarios and macro collision risk models were established, and the waters with higher maritime traffic risks were generated. To better evaluate the risk of ship collision candidates during routing waterways, an improved adaptive bandwidth kernel density estimation (KDE) is proposed. This proposed algorithm is used for evaluating risk reduction of the ship routing system, which schedules and adjusts maritime traffic in congested harbor waterways. Larger bandwidth can make the hot spot region more obvious on a global scale. Moreover, the bandwidth is positively correlated with the dispersion of points. Concerning the data with sparse point distribution, a larger bandwidth should be used whereas, for data with dense points of interest, a smaller bandwidth should be considered. The results show that the KDE, with optimized bandwidth, can fit the ship encountering distribution and obtain the frequent spots for ship encountering. The comparison between KDE results before and after the ship routing system shows that the hot spots of ship collision candidates are reduced after the ship routing waterway is established.
{"title":"Risk Assessment Based on KDE of Ship Collision Candidates for Ship Routing Waterway","authors":"Han Xue, Tian Chai","doi":"10.5957/josr.12210045","DOIUrl":"https://doi.org/10.5957/josr.12210045","url":null,"abstract":"To study the geographical distribution characteristics of maritime traffic risks, statistical representations of potential accident scenarios and macro collision risk models were established, and the waters with higher maritime traffic risks were generated. To better evaluate the risk of ship collision candidates during routing waterways, an improved adaptive bandwidth kernel density estimation (KDE) is proposed. This proposed algorithm is used for evaluating risk reduction of the ship routing system, which schedules and adjusts maritime traffic in congested harbor waterways. Larger bandwidth can make the hot spot region more obvious on a global scale. Moreover, the bandwidth is positively correlated with the dispersion of points. Concerning the data with sparse point distribution, a larger bandwidth should be used whereas, for data with dense points of interest, a smaller bandwidth should be considered. The results show that the KDE, with optimized bandwidth, can fit the ship encountering distribution and obtain the frequent spots for ship encountering. The comparison between KDE results before and after the ship routing system shows that the hot spots of ship collision candidates are reduced after the ship routing waterway is established.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":"29 24","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138602566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many tools have been developed to simulate unmanned underwater vehicle (UUV) motion and autonomous behaviors to evaluate UUV capabilities. However, there is no simulator that performs real-time modeling of the complex hydrodynamic interaction forces that a UUV experiences when operating near a moving submarine. These hydrodynamic interactions must be determined in real time to simulate the launch and recovery of UUVs from submarines. Potential flow models may be fast enough to solve the hydrodynamic interactions in real time, but by oversimplifying the physics and neglecting viscosity, they introduce inaccuracies into the simulations. Computational fluid dynamics (CFD) is capable of accurately modeling these hydrodynamic interactions, but simulations take hours or days to solve. To overcome this obstacle, a machine learning method known as Gaussian process (GP) regression is used to create a surrogate reduced-order-model that predicts the hydrodynamic interactions in real time. The GP regression model is trained by actively sampling CFD simulations in order to accurately model complex hydrodynamic interactions. This new approach allows the GP regression model to be incorporated into a UUV motion simulator and evaluate how the UUV is affected by the hydrodynamic interactions. Operating envelopes are developed that outline regions where the UUV safely overcomes the hydrodynamic interactions and where the UUV is overpowered and collides with the submarine. By incorporating this surrogate model into the autonomy architecture, new autonomous behaviors are created that compensate for the hydrodynamic interactions by adjusting the desired UUV heading and speed which allows it to better stay on course.
{"title":"Unmanned Underwater Vehicle Autonomy and Control near Submarines Using Actively Sampled Surrogates","authors":"Brady M. Hammond, T. Sapsis","doi":"10.5957/josr.02230004","DOIUrl":"https://doi.org/10.5957/josr.02230004","url":null,"abstract":"Many tools have been developed to simulate unmanned underwater vehicle (UUV) motion and autonomous behaviors to evaluate UUV capabilities. However, there is no simulator that performs real-time modeling of the complex hydrodynamic interaction forces that a UUV experiences when operating near a moving submarine. These hydrodynamic interactions must be determined in real time to simulate the launch and recovery of UUVs from submarines. Potential flow models may be fast enough to solve the hydrodynamic interactions in real time, but by oversimplifying the physics and neglecting viscosity, they introduce inaccuracies into the simulations. Computational fluid dynamics (CFD) is capable of accurately modeling these hydrodynamic interactions, but simulations take hours or days to solve. To overcome this obstacle, a machine learning method known as Gaussian process (GP) regression is used to create a surrogate reduced-order-model that predicts the hydrodynamic interactions in real time. The GP regression model is trained by actively sampling CFD simulations in order to accurately model complex hydrodynamic interactions. This new approach allows the GP regression model to be incorporated into a UUV motion simulator and evaluate how the UUV is affected by the hydrodynamic interactions. Operating envelopes are developed that outline regions where the UUV safely overcomes the hydrodynamic interactions and where the UUV is overpowered and collides with the submarine. By incorporating this surrogate model into the autonomy architecture, new autonomous behaviors are created that compensate for the hydrodynamic interactions by adjusting the desired UUV heading and speed which allows it to better stay on course.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":"48 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139208952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An improved emergency blow model is proposed, which is based on the traditional emergency blow model and takes into account the influence of compressed air overflows from flood holes in the later stage of blowing. In order to verify the prediction accuracy of the improved emergency blow model for tank blowing, the full-scale model experiment of tank blowing was conducted to investigate the effects of air source volume, air source initial pressure, and flood holes diameters on blowing. The process of air release from bottle and main ballast tank drainage can be accurately simulated by the improved emergency blow model, and the prediction error of tank air peak pressure is shown to be <10%. Additionally, it is found that the air source volume has no effect on the tank’s air peak pressure or tank drainage rate. By analyzing the dynamic characteristics of tank air pressure, it is found that the dynamic change trend of air pressure differs between flood holes with small and large diameters. In the small diameter conditions, the air pressure reaches the maximum when the compressed air just enters the tank; however, under large diameter conditions, the peak pressure comes before the accumulated air pressure is released. The experiment and simulation demonstrate that increasing the area of the flood holes has a decreasing effect on the amount of air accumulated in the tank, and that the decreasing effect becomes more pronounced as the air source initial pressure increases. To carry out military operations, submarines are deployed both underwater and close to the open surface. About 170 submarines have sunk since they were originally created as a result of an accident, such as a fire, explosion, malfunction, grounding, or collision (Park & Kim 2017). Submarines run the risk of losing safety control in these critical situations. The best method of self-rescue is emergency floating to the surface to prevent bottoming or going deeper than allowed (Liu et al. 2009). A key factor in emergency rising to the water’s surface is the compressed air blowing mechanism. In such an operation, supplying air to the main ballast tank and blowing out ballast water should be used to achieve positive buoyancy or recover a positive pitching moment, which can be used to restore the safe depth of the submarine. Emergency blow is the term used to describe the process of directly supplying air to the main ballast tank without using a high-pressure valve column. The emergency blow is explored in this work because its influence is significantly greater than that of usual blowing, or traditional blowing.
在传统应急吹气模型的基础上，提出了一种改进的应急吹气模型，该模型考虑了吹气后期洪洞溢出压缩空气的影响。为了验证改进后的罐吹应急吹气模型的预测准确性，进行了罐吹气全尺寸模型试验，研究气源体积、气源初始压力、泛孔直径对吹气的影响。改进后的应急吹气模型能准确模拟出瓶内放气和主压载舱排水过程，罐内空气峰值压力预测误差<10%。此外，还发现气源容积对储气罐的空气峰值压力和储气罐排水速率没有影响。通过对储罐气压动态特性的分析，发现小孔与小孔的气压动态变化趋势是不同的。在小口径工况下，压缩空气刚进入储气罐时气压最大;然而，在大直径条件下，峰值压力出现在累积空气压力释放之前。实验和仿真结果表明，增大洪洞面积对储气罐内积气量有减小作用，且随着气源初始压力的增大，减小作用更为明显。为了执行军事行动，潜艇既部署在水下，也部署在靠近开阔水面的地方。自最初建造以来，大约有170艘潜艇因火灾、爆炸、故障、搁浅或碰撞等事故而沉没(Park & Kim 2017)。在这些危急情况下，潜艇有失去安全控制的危险。最好的自救方法是紧急浮到水面，以防止触底或超过允许的深度(Liu et al. 2009)。紧急浮上水面的一个关键因素是压缩空气吹气机构。在这种操作中，应采用向主压载舱供气和吹出压载水的方法，以获得正浮力或恢复正俯仰力矩，用于恢复潜艇的安全深度。紧急吹气是指不使用高压阀柱直接向主压载舱送气的过程。由于紧急吹风的影响明显大于常规吹风或传统吹风，因此本文对紧急吹风进行了探讨。
{"title":"An Improved Emergency Blow Theoretical Model for Naval Submarine Blowing System and Experimental Verification","authors":"Qi Yi, Kaiyin Zhang, Boqun Lin, Wanliang Zhang","doi":"10.5957/josr.07220022","DOIUrl":"https://doi.org/10.5957/josr.07220022","url":null,"abstract":"\u0000 \u0000 An improved emergency blow model is proposed, which is based on the traditional emergency blow model and takes into account the influence of compressed air overflows from flood holes in the later stage of blowing. In order to verify the prediction accuracy of the improved emergency blow model for tank blowing, the full-scale model experiment of tank blowing was conducted to investigate the effects of air source volume, air source initial pressure, and flood holes diameters on blowing. The process of air release from bottle and main ballast tank drainage can be accurately simulated by the improved emergency blow model, and the prediction error of tank air peak pressure is shown to be <10%. Additionally, it is found that the air source volume has no effect on the tank’s air peak pressure or tank drainage rate. By analyzing the dynamic characteristics of tank air pressure, it is found that the dynamic change trend of air pressure differs between flood holes with small and large diameters. In the small diameter conditions, the air pressure reaches the maximum when the compressed air just enters the tank; however, under large diameter conditions, the peak pressure comes before the accumulated air pressure is released. The experiment and simulation demonstrate that increasing the area of the flood holes has a decreasing effect on the amount of air accumulated in the tank, and that the decreasing effect becomes more pronounced as the air source initial pressure increases.\u0000 \u0000 \u0000 \u0000 To carry out military operations, submarines are deployed both underwater and close to the open surface. About 170 submarines have sunk since they were originally created as a result of an accident, such as a fire, explosion, malfunction, grounding, or collision (Park & Kim 2017). Submarines run the risk of losing safety control in these critical situations. The best method of self-rescue is emergency floating to the surface to prevent bottoming or going deeper than allowed (Liu et al. 2009). A key factor in emergency rising to the water’s surface is the compressed air blowing mechanism. In such an operation, supplying air to the main ballast tank and blowing out ballast water should be used to achieve positive buoyancy or recover a positive pitching moment, which can be used to restore the safe depth of the submarine. Emergency blow is the term used to describe the process of directly supplying air to the main ballast tank without using a high-pressure valve column. The emergency blow is explored in this work because its influence is significantly greater than that of usual blowing, or traditional blowing.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42886046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering the main structures of typical underwater vehicles, three types of numerical model are established, including the beam model, the shell-beam model, and the whole shell model. The results of the three models are compared during the analyses of global vibration, local vibration of cabins, and underwater acoustic radiation. Giving consideration to both the computational cost and accuracy, the proposed shell-beam model is appropriate for the calculation of low-medium frequency acoustic radiation of the main structures of underwater vehicles. The rationality and the frequency range of application of the shell-beam model are verified by calculating the fluid-structure coupling vibration response and the underwater acoustic radiation of the hull subjected to the transverse load excitation, which also demonstrate the significance of this model in engineering practice. The calculation research on the acoustic radiation of typical underwater vehicle structures can be generally divided into three types based on the calculation methods: analytical methods (Caresta & Kessissoglou 2009), numerical methods, and analytical-numerical hybrid methods (Zhu et al. 2014; Meyer et al. 2016; Qu et al. 2017). The analytical methods can be used for the study of basic laws and mechanisms, and can also be treated as benchmarks for numerical algorithms. However, when it comes to real ships with complex structures, it is difficult to accurately predict the forced vibration and underwater acoustic radiation characteristics by analytical methods. Previously, due to the limitation of the computer hardware, a whole ship was usually simplified as a free–free beam of variable cross section (the hull beam) when conducting the analysis of global vibration. In recent years, with the development of computer technology, whole shell models are usually established during analyses of the low-medium frequency vibration and acoustic radiation of underwater vehicles.
针对典型水下航行器的主要结构，建立了三种类型的数值模型，包括梁模型、壳梁模型和全壳模型。在分析舱室整体振动、局部振动和水下声辐射时，对三种模型的结果进行了比较。考虑到计算成本和精度，所提出的壳梁模型适用于水下航行器主要结构的中低频声辐射计算。通过计算船体在横向载荷激励下的流固耦合振动响应和水下声辐射，验证了壳梁模型应用的合理性和频率范围，也说明了该模型在工程实践中的意义。基于计算方法，典型水下航行器结构声辐射的计算研究通常可分为三类：分析方法（Caresta&Kessissoglou 2009）、数值方法和分析-数值混合方法（Zhu et al.2014；Meyer et al.2016；Qu et al.2017）。分析方法可用于研究基本规律和机理，也可作为数值算法的基准。然而，当涉及到具有复杂结构的真实船舶时，很难通过分析方法准确预测强迫振动和水下声辐射特性。以前，由于计算机硬件的限制，在进行全局振动分析时，通常将整艘船简化为变截面的自由-自由梁（船体梁）。近年来，随着计算机技术的发展，在分析水下航行器的中低频振动和声辐射时，通常会建立完整的壳体模型。
{"title":"Numerical Modeling of the Low-Medium Frequency Vibration and Acoustic Radiation of Underwater Vehicles","authors":"Ming-song Zou, Zhen-Wu Xie, Ling-Wen Jiang","doi":"10.5957/josr.12220032","DOIUrl":"https://doi.org/10.5957/josr.12220032","url":null,"abstract":"Considering the main structures of typical underwater vehicles, three types of numerical model are established, including the beam model, the shell-beam model, and the whole shell model. The results of the three models are compared during the analyses of global vibration, local vibration of cabins, and underwater acoustic radiation. Giving consideration to both the computational cost and accuracy, the proposed shell-beam model is appropriate for the calculation of low-medium frequency acoustic radiation of the main structures of underwater vehicles. The rationality and the frequency range of application of the shell-beam model are verified by calculating the fluid-structure coupling vibration response and the underwater acoustic radiation of the hull subjected to the transverse load excitation, which also demonstrate the significance of this model in engineering practice.\u0000 \u0000 \u0000 \u0000 The calculation research on the acoustic radiation of typical underwater vehicle structures can be generally divided into three types based on the calculation methods: analytical methods (Caresta & Kessissoglou 2009), numerical methods, and analytical-numerical hybrid methods (Zhu et al. 2014; Meyer et al. 2016; Qu et al. 2017). The analytical methods can be used for the study of basic laws and mechanisms, and can also be treated as benchmarks for numerical algorithms. However, when it comes to real ships with complex structures, it is difficult to accurately predict the forced vibration and underwater acoustic radiation characteristics by analytical methods. Previously, due to the limitation of the computer hardware, a whole ship was usually simplified as a free–free beam of variable cross section (the hull beam) when conducting the analysis of global vibration. In recent years, with the development of computer technology, whole shell models are usually established during analyses of the low-medium frequency vibration and acoustic radiation of underwater vehicles.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48007296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vivien Luthy, François Grinnaert, J. Billard, Jocelyn Rapp
The International Maritime Organization (IMO) provides criteria to assess the vulnerability of ships toward the phenomenon of parametric roll. Such long-term vulnerability assessments permit to qualify statistically the ships vulnerability regarding parametric roll. However, it does not permit to assess the risk of parametric roll in real time. Thus, researchers and private company have developed methods and software to evaluate this risk using the real-time ship motions provided by the onboard inertial unit. Those methods detect parametric roll events when it appears and warn the officer of the watch of the immediate danger. This paper presents an innovative real-time detection method and its validation. The detection method considers physical conditions required for parametric roll to appear. Especially, it considers the coupling between the roll and pitch motions. The method and its associated parametric roll alarm are entirely described. The results show that the method correctly identifies parametric roll in regular longitudinal waves and do not lead to false detection in regular beam waves. A statistical study in irregular waves based on simulated data presents very promising results with a parametric roll detection rate in head seas above 80% when heavy roll motions appear and a false detection rate in beam seas below 4%. Finally, a 2.5-day full-scale validation on a container ship provides promising results. The container ships, with typical hull shape presenting flat stern and pronounced bow flare, are especially subject to parametric roll. Operationally, several accidents which have led to the loss of containers at sea may be imputed to this phenomenon (France et al. 2003; Carmel 2006; MAIB 2020; DMAIB 2022). Following the accidents of the C11-class container ship (France et al. 2003) and of the Maersk Carolina (Carmel 2006), both due to parametric roll, insurers asked the shipowners to take measures to avoid such failure to appear (Dølhie 2006). Two solutions are rapidly developed to answer this request. The first one is developed by SeaSense and named SeaSense Monitoring (Nielsen et al. 2006).
国际海事组织(IMO)提供了评估船舶对参数横摇现象脆弱性的准则。这种长期易损性评估可以从统计上确定船舶在参数侧倾方面的易损性。然而，它不允许实时评估参数滚动的风险。因此，研究人员和私营公司已经开发出方法和软件，利用机载惯性单元提供的实时船舶运动来评估这种风险。这些方法检测参数滚动事件，当它出现，并警告值班人员的直接危险。本文提出了一种新颖的实时检测方法及其验证。该检测方法考虑了参数化辊出现所需的物理条件。特别考虑了横摇和俯仰运动之间的耦合。详细介绍了该方法及其相关的参数滚动报警方法。结果表明，该方法能够正确识别规则纵波中的参数横摇，不会导致规则纵波中的误检。基于模拟数据的不规则波统计研究结果表明，当出现大横摇运动时，首浪的参数横摇检测率在80%以上，横浪的误检率在4%以下。最后，在一艘集装箱船上进行了为期2.5天的全尺寸验证，结果令人鼓舞。典型的集装箱船船型为平尾和明显的艏耀斑，尤其容易受到参数横摇的影响。在操作上，导致海上集装箱损失的几起事故可归咎于这一现象(France et al. 2003;卡梅尔2006年;MAIB 2020;DMAIB 2022)。继c11级集装箱船(France et al. 2003)和Maersk Carolina (Carmel 2006)事故后，由于参数滚转，保险公司要求船东采取措施避免此类故障的出现(Dølhie 2006)。为了回答这一要求，迅速开发了两种解决方案。第一个是由SeaSense开发的，命名为SeaSense Monitoring (Nielsen et al. 2006)。
{"title":"Real-Time Identification of Parametric Roll","authors":"Vivien Luthy, François Grinnaert, J. Billard, Jocelyn Rapp","doi":"10.5957/josr.07220021","DOIUrl":"https://doi.org/10.5957/josr.07220021","url":null,"abstract":"\u0000 \u0000 The International Maritime Organization (IMO) provides criteria to assess the vulnerability of ships toward the phenomenon of parametric roll. Such long-term vulnerability assessments permit to qualify statistically the ships vulnerability regarding parametric roll. However, it does not permit to assess the risk of parametric roll in real time. Thus, researchers and private company have developed methods and software to evaluate this risk using the real-time ship motions provided by the onboard inertial unit. Those methods detect parametric roll events when it appears and warn the officer of the watch of the immediate danger. This paper presents an innovative real-time detection method and its validation. The detection method considers physical conditions required for parametric roll to appear. Especially, it considers the coupling between the roll and pitch motions. The method and its associated parametric roll alarm are entirely described. The results show that the method correctly identifies parametric roll in regular longitudinal waves and do not lead to false detection in regular beam waves. A statistical study in irregular waves based on simulated data presents very promising results with a parametric roll detection rate in head seas above 80% when heavy roll motions appear and a false detection rate in beam seas below 4%. Finally, a 2.5-day full-scale validation on a container ship provides promising results.\u0000 \u0000 \u0000 \u0000 The container ships, with typical hull shape presenting flat stern and pronounced bow flare, are especially subject to parametric roll. Operationally, several accidents which have led to the loss of containers at sea may be imputed to this phenomenon (France et al. 2003; Carmel 2006; MAIB 2020; DMAIB 2022). Following the accidents of the C11-class container ship (France et al. 2003) and of the Maersk Carolina (Carmel 2006), both due to parametric roll, insurers asked the shipowners to take measures to avoid such failure to appear (Dølhie 2006). Two solutions are rapidly developed to answer this request. The first one is developed by SeaSense and named SeaSense Monitoring (Nielsen et al. 2006).\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48068154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A practical criterion which can be used for assessing the course-keeping capability of a ship in following waves, is proposed and evaluated. Presently, it accounts for regular waves and it accrued from an analytical estimation of the course instability region’s boundary by applying the method of harmonic balance. The calculation is performed with regard to the third-order yaw equation, derived from a classic sway-yaw-rudder model of ship maneuvering motions, with time-dependent coefficients at two places, which is like a Mathieu-type equation extended to third order. The proposed analytical criterion was evaluated thoroughly against simulations with regard to this sway-yaw model and it was found to be adequately accurate. A supplementary quasi-static yaw stability criterion (fitting to ship operation with frequency of encounter, with respect to the waves, close to zero) was also considered in order to determine which one yields more stringent requirements, for various operating conditions. The proposed criterion could be an extra vulnerability check for broaching-to, in the context of the Second Generation Intact Stability Criteria. The difficulties of steering of ships in following seas have received the attention of the research community since more than 70 years ago (Davidson 1948). A relevant direction of research refers to the avoidance of the broaching-to instability and, in particular, to the development of practical criteria that could ensure sufficient course-keeping capability for a ship encountering steep following waves. Some classic works on this topic, such as those of DuCane and Goodrich (1962), Wahab and Swaan (1964), and Motora et al. (1981), were focused on the quasi-static condition of a ship on the wave which could be practically realized if the ship was advancing with speed equal to the wave celerity (zero frequency of encounter). As implied, these works were essentially focused on the avoidance of a type of broaching-to instability that is preceded by the realization of surf-riding, a phenomenon where the ship is forced to move with the wave, usually riding a downslope.
{"title":"A Vulnerability Criterion of Dynamic Instability for Ship Course-Keeping in Following Waves","authors":"Vicky Margari, K. Spyrou","doi":"10.5957/josr.03220010","DOIUrl":"https://doi.org/10.5957/josr.03220010","url":null,"abstract":"\u0000 \u0000 A practical criterion which can be used for assessing the course-keeping capability of a ship in following waves, is proposed and evaluated. Presently, it accounts for regular waves and it accrued from an analytical estimation of the course instability region’s boundary by applying the method of harmonic balance. The calculation is performed with regard to the third-order yaw equation, derived from a classic sway-yaw-rudder model of ship maneuvering motions, with time-dependent coefficients at two places, which is like a Mathieu-type equation extended to third order. The proposed analytical criterion was evaluated thoroughly against simulations with regard to this sway-yaw model and it was found to be adequately accurate. A supplementary quasi-static yaw stability criterion (fitting to ship operation with frequency of encounter, with respect to the waves, close to zero) was also considered in order to determine which one yields more stringent requirements, for various operating conditions. The proposed criterion could be an extra vulnerability check for broaching-to, in the context of the Second Generation Intact Stability Criteria.\u0000 \u0000 \u0000 \u0000 The difficulties of steering of ships in following seas have received the attention of the research community since more than 70 years ago (Davidson 1948). A relevant direction of research refers to the avoidance of the broaching-to instability and, in particular, to the development of practical criteria that could ensure sufficient course-keeping capability for a ship encountering steep following waves. Some classic works on this topic, such as those of DuCane and Goodrich (1962), Wahab and Swaan (1964), and Motora et al. (1981), were focused on the quasi-static condition of a ship on the wave which could be practically realized if the ship was advancing with speed equal to the wave celerity (zero frequency of encounter). As implied, these works were essentially focused on the avoidance of a type of broaching-to instability that is preceded by the realization of surf-riding, a phenomenon where the ship is forced to move with the wave, usually riding a downslope.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47543402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-14DOI: 10.5957/jsr.1969.13.1.53
G. R. Hough, J. P. Moran
The performance of a two-dimensional hydrofoil of arbitrary camber, moving at arbitrary Froude number at a constant depth below a free surface, is considered. The treatment is based upon the use of singularity distributions and thin foil theory. By assuming an appropriate series form for the vortex distribution representing the hydrofoil, it is shown that the problem can be reduced to the solution of a set of linear algebraic equations. These are solved by a collocation procedure. Numerical results for the performance characteristics are then given for several hydrofoil configurations, submergence depths, and Froude numbers. These indicate that operation at Froude numbers greater than about ten is practically equivalent to operation at infinite Froude number. However, at lower values of the Froude number and for all the configurations considered, Froude number effects are important, even at submergence depths of several chord lengths.
{"title":"Froude Number Effects on Two-Dimensional Hydrofoils","authors":"G. R. Hough, J. P. Moran","doi":"10.5957/jsr.1969.13.1.53","DOIUrl":"https://doi.org/10.5957/jsr.1969.13.1.53","url":null,"abstract":"The performance of a two-dimensional hydrofoil of arbitrary camber, moving at arbitrary Froude number at a constant depth below a free surface, is considered. The treatment is based upon the use of singularity distributions and thin foil theory. By assuming an appropriate series form for the vortex distribution representing the hydrofoil, it is shown that the problem can be reduced to the solution of a set of linear algebraic equations. These are solved by a collocation procedure. Numerical results for the performance characteristics are then given for several hydrofoil configurations, submergence depths, and Froude numbers. These indicate that operation at Froude numbers greater than about ten is practically equivalent to operation at infinite Froude number. However, at lower values of the Froude number and for all the configurations considered, Froude number effects are important, even at submergence depths of several chord lengths.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41409765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present experimental results of resonant free surface oscillations within three circular moonpools arranged in tandem at forward, central, and aft positions of a fixed rectangular vessel in head waves. The piston mode resonance frequency is primarily captured, which decreases with the increase in the vessel draft. The aim is to study the effect of body diffraction on the free surface amplitude and phase of the oscillating water columns at the three locations. The results indicate that, in general, the forward moonpool has the highest response amplitude, whereas the relative amplitudes of the central and aft moonpools depend on the wave frequency. It is observed that the nondimensional response amplitude increases nonlinearly with decreasing wave steepness close to the resonance frequency, while the effect diminishes at lower wave frequencies. The oscillation phase differences between the moonpools show effects of wave-body interaction, a phenomenon dependent on the vessel draft and wave frequency. Finally, the study includes a comparison of the responses at the three moonpool locations between multiple and single configurations. A moonpool is a vertical opening through the ship deck and open to the sea at the bottom, which is installed in vessels specialized in certain offshore operations. Resonant water column oscillations are encountered in moonpools (Aalbers 1984) due to vessel operations in waves. On the other hand, oscillating water columns (OWCs) have been extensively researched, primarily due to their potential for ocean wave energy conversion (Evans 1978; Heath 2012; Falcão & Henriques 2016). Now, considering design perspectives, the focus of the studies on water column resonance in waves depends on the specific marine application. For example, wave energy converters would require maximized OWC responses for efficient energy capture (Evans & Porter 1995; Morris-Thomas et al. 2007), while large free surface oscillations within moonpools of drillships have adverse effects on the vessel dynamics (Fakuda 1977).
{"title":"Resonant Oscillations within Multiple Moonpools for a Fixed Rectangular Vessel","authors":"Suraj Garad, A. Bhattacharyya, R. Datta","doi":"10.5957/josr.01220004","DOIUrl":"https://doi.org/10.5957/josr.01220004","url":null,"abstract":"\u0000 \u0000 We present experimental results of resonant free surface oscillations within three circular moonpools arranged in tandem at forward, central, and aft positions of a fixed rectangular vessel in head waves. The piston mode resonance frequency is primarily captured, which decreases with the increase in the vessel draft. The aim is to study the effect of body diffraction on the free surface amplitude and phase of the oscillating water columns at the three locations. The results indicate that, in general, the forward moonpool has the highest response amplitude, whereas the relative amplitudes of the central and aft moonpools depend on the wave frequency. It is observed that the nondimensional response amplitude increases nonlinearly with decreasing wave steepness close to the resonance frequency, while the effect diminishes at lower wave frequencies. The oscillation phase differences between the moonpools show effects of wave-body interaction, a phenomenon dependent on the vessel draft and wave frequency. Finally, the study includes a comparison of the responses at the three moonpool locations between multiple and single configurations.\u0000 \u0000 \u0000 \u0000 A moonpool is a vertical opening through the ship deck and open to the sea at the bottom, which is installed in vessels specialized in certain offshore operations. Resonant water column oscillations are encountered in moonpools (Aalbers 1984) due to vessel operations in waves. On the other hand, oscillating water columns (OWCs) have been extensively researched, primarily due to their potential for ocean wave energy conversion (Evans 1978; Heath 2012; Falcão & Henriques 2016). Now, considering design perspectives, the focus of the studies on water column resonance in waves depends on the specific marine application. For example, wave energy converters would require maximized OWC responses for efficient energy capture (Evans & Porter 1995; Morris-Thomas et al. 2007), while large free surface oscillations within moonpools of drillships have adverse effects on the vessel dynamics (Fakuda 1977).\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42364533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurate prediction of planing hull resistance is a difficult task due to complex hydrodynamic interactions at high speeds and is often performed by three methods: model testing, empirical formulas, and computational fluid dynamics (CFD). Model testing provides the most accurate results, but is usually only used in cases of necessity due to time and cost, whereas empirical formulas and the CFD method do not always provide results with the expected accuracy and reliability. Therefore, this paper will present methods to improve and ensure the accuracy of planing hull resistance values predicted by Savitsky’s empirical formula based on using our modified computation procedure, and by the CFD method based on ensuring the quality of 3D hull mesh and defining the simulation parameters suitable for a study planing hull. This study has been applied to Vietnam’s large displacement high speed passenger vessel with design symbol K88 and obtained good results with the deviations between the resistance model test data and the corresponding values predicted by the Savitsky method using our modified computation procedure, and by the XFlow CFD software using our suitable inputs in calculation cases are within 65% and 63%, respectively. In planing hull design, accurate prediction of its resistance is a difficult task due to complex hydrodynamic interactions at high speeds and is often performed by three methods: model testing, empirical formulas, and computational fluid dynamics (CFD). Model testing is the most reliable approach but it is expensive and time-consuming, so it is often used in cases where it is necessary, or used to verify and validate the results predicted by others. Also, since dynamic similarity cannot be fulfilled in model tests, it is necessary to use Froude or Prohaska methods to extrapolate results from model scale to full scale, which causes certain errors. Empirical formulas or graphs are established based on the systematization of resistance data of series model tests with hull form similarities (Holtrop & Mennen 1982; Faltinsen 2006). As a result, there are many different empirical resistance formulas and graphs depending on the type of ship used in the model tests. Table 1 shows some common empirical formulas or graphs for planing hull resistance with different ranges of hull parameters that can be found in related documents, such as Kafali (1959), Nordstrom (1951), Groot (1951), Almeter (1993), etc.
{"title":"Methods to Improve Accuracy of Planing Hull Resistance Prediction","authors":"Q. Huynh, T. G. Tran","doi":"10.5957/josr.05210016","DOIUrl":"https://doi.org/10.5957/josr.05210016","url":null,"abstract":"\u0000 \u0000 Accurate prediction of planing hull resistance is a difficult task due to complex hydrodynamic interactions at high speeds and is often performed by three methods: model testing, empirical formulas, and computational fluid dynamics (CFD). Model testing provides the most accurate results, but is usually only used in cases of necessity due to time and cost, whereas empirical formulas and the CFD method do not always provide results with the expected accuracy and reliability. Therefore, this paper will present methods to improve and ensure the accuracy of planing hull resistance values predicted by Savitsky’s empirical formula based on using our modified computation procedure, and by the CFD method based on ensuring the quality of 3D hull mesh and defining the simulation parameters suitable for a study planing hull. This study has been applied to Vietnam’s large displacement high speed passenger vessel with design symbol K88 and obtained good results with the deviations between the resistance model test data and the corresponding values predicted by the Savitsky method using our modified computation procedure, and by the XFlow CFD software using our suitable inputs in calculation cases are within 65% and 63%, respectively.\u0000 \u0000 \u0000 \u0000 In planing hull design, accurate prediction of its resistance is a difficult task due to complex hydrodynamic interactions at high speeds and is often performed by three methods: model testing, empirical formulas, and computational fluid dynamics (CFD). Model testing is the most reliable approach but it is expensive and time-consuming, so it is often used in cases where it is necessary, or used to verify and validate the results predicted by others. Also, since dynamic similarity cannot be fulfilled in model tests, it is necessary to use Froude or Prohaska methods to extrapolate results from model scale to full scale, which causes certain errors. Empirical formulas or graphs are established based on the systematization of resistance data of series model tests with hull form similarities (Holtrop & Mennen 1982; Faltinsen 2006). As a result, there are many different empirical resistance formulas and graphs depending on the type of ship used in the model tests. Table 1 shows some common empirical formulas or graphs for planing hull resistance with different ranges of hull parameters that can be found in related documents, such as Kafali (1959), Nordstrom (1951), Groot (1951), Almeter (1993), etc.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45869973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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