When an underwater vehicle performs tasks, such as power recharge, air exchange, deployment, and retrieval near the surface, the low-frequency suction force and pitch moment will interfere with its motion. This paper presents a study on the effect of second-order difference-frequency wave force on the motions of the DARPA SUBOFF model at various submergence depths and environmental conditions. Ignoring the second-order wave force component induced by the second-order difference-frequency force may underestimate the second-order effect in irregular waves in the time domain. Comparisons were made between Newman’s approximation, which sets the off-diagonal difference-frequency quadratic transfer function (QTF) value to the average over the corresponding diagonal values, and the full QTFs based on the Pinkster approximation in the frequency and time domains. The QTFs-based prediction is significantly larger values than Newman’s approximation. Time-domain simulations were conducted, to investigate the effect of the second-order difference-frequency wave loads on motion responses at different nondimensional submergence depths and various sea conditions. The results of the computation indicate that ignoring the second-order difference-frequency wave force may underestimate the motion and dynamic responses of underwater vehicles; in addition, the pitch and heave motion responses are dominated by the low-frequency response. When an underwater vehicle travels close to the water surface, it experiences an upward force and pitch moment, known as surface suction. This can significantly affect the underwater vehicle’s behavior when power recharge, air exchange, deployment, and retrieval are incorporated into the underwater vehicle simulations. Veillon et al. (1996) noted that for a 10,000-ton submarine at a depth of 50 m, the surface suction due to waves will require around 20–30 tons of compensation to stop the submarine from surfacing. In addition, Hirom (1974) indicated that in waves, the fluctuating forces on a submarine can be on the order of 1000 kN, with a steady component of approximately 10 kN. In calm water, suction occurs owing to a higher flow velocity and a lower pressure above an underwater vehicle when sailing near the surface, and the wave pattern generated by the underwater vehicle complicates the surface effect. The longitudinal position of the center of pressure is after the amidships, which induces the pitch moment. In the presence of waves, the first-order wave force, which is the oscillatory force at the wave frequency, acts on the underwater vehicle. In addition, waves and model motions induce low-frequency suction force and pitch moment. Using any internal compensation and control surfaces to offset the induced suction force and pitch moment requires a good and early understanding of the magnitude of these forces, for designing sufficient-capacity compensation tanks (Crossland 2013). Therefore, the surface suction and pitch m
{"title":"The Effect of the Second-order Difference-frequency Wave Force on the Motions of an Underwater Vehicle Near the Surface","authors":"R. Qin, Haining Lu, Jia-hong Chen","doi":"10.5957/josr.05220016","DOIUrl":"https://doi.org/10.5957/josr.05220016","url":null,"abstract":"\u0000 \u0000 When an underwater vehicle performs tasks, such as power recharge, air exchange, deployment, and retrieval near the surface, the low-frequency suction force and pitch moment will interfere with its motion. This paper presents a study on the effect of second-order difference-frequency wave force on the motions of the DARPA SUBOFF model at various submergence depths and environmental conditions. Ignoring the second-order wave force component induced by the second-order difference-frequency force may underestimate the second-order effect in irregular waves in the time domain. Comparisons were made between Newman’s approximation, which sets the off-diagonal difference-frequency quadratic transfer function (QTF) value to the average over the corresponding diagonal values, and the full QTFs based on the Pinkster approximation in the frequency and time domains. The QTFs-based prediction is significantly larger values than Newman’s approximation. Time-domain simulations were conducted, to investigate the effect of the second-order difference-frequency wave loads on motion responses at different nondimensional submergence depths and various sea conditions. The results of the computation indicate that ignoring the second-order difference-frequency wave force may underestimate the motion and dynamic responses of underwater vehicles; in addition, the pitch and heave motion responses are dominated by the low-frequency response.\u0000 \u0000 \u0000 \u0000 When an underwater vehicle travels close to the water surface, it experiences an upward force and pitch moment, known as surface suction. This can significantly affect the underwater vehicle’s behavior when power recharge, air exchange, deployment, and retrieval are incorporated into the underwater vehicle simulations. Veillon et al. (1996) noted that for a 10,000-ton submarine at a depth of 50 m, the surface suction due to waves will require around 20–30 tons of compensation to stop the submarine from surfacing. In addition, Hirom (1974) indicated that in waves, the fluctuating forces on a submarine can be on the order of 1000 kN, with a steady component of approximately 10 kN. In calm water, suction occurs owing to a higher flow velocity and a lower pressure above an underwater vehicle when sailing near the surface, and the wave pattern generated by the underwater vehicle complicates the surface effect. The longitudinal position of the center of pressure is after the amidships, which induces the pitch moment. In the presence of waves, the first-order wave force, which is the oscillatory force at the wave frequency, acts on the underwater vehicle. In addition, waves and model motions induce low-frequency suction force and pitch moment. Using any internal compensation and control surfaces to offset the induced suction force and pitch moment requires a good and early understanding of the magnitude of these forces, for designing sufficient-capacity compensation tanks (Crossland 2013). Therefore, the surface suction and pitch m","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48986120","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}
Yingyuan Wang, J. Gu, Mingyang Yang, K. Deng, Lei Cui, Yuehua Qian
Low-speed two-stroke diesel engines are widely employed in the marine industry, especially in tanks, owing to their advantages of fuel economy and reliability. However, with the emerging ultra-long-stroke trend, existing scavenging models, which are based on the configuration of cylinders with short strokes, are no longer applicable. In this study, we investigate the flow field and residual exhaust gas distribution in a cylinder using particle image velocimetry and computational fluid dynamics (CFD) simulations. The result shows a strong Burgers vortex structure upstream of the scavenger flow and dissipates gradually as it moves downstream. Furthermore, the scavenging process comprises three processes according to the detailed CFD analysis: displacement, mixing scavenging, and short circuit. Inspired by the results, a tailored empirical model of ultra-long-stroke uniflow scavenging comprising three sub-models is proposed. Specifically, a logarithmic relationship between the concentration level and scavenging deliver ratio is proposed to describe the mixing scavenging process. Finally, the model was validated against CFD results. The results demonstrate that the discrepancy in the scavenging efficiency curve predicted by this model and CFD is less than 1%, thereby demonstrating model reliability. Owing to the advantages of a large power range, high thermal efficiency, low fuel consumption rate, and good reliability, marine low-speed engines are widely used to provide power to civil ships (Heywood 1999). The market for low-speed engines is vast and is improving the performance of low-speed engines through research has great economic and environmental significance (Woodyard 2004). To meet the requirements of ship owners for lower fuel consumption and the IMO’s regulation of halving the greenhouse gas emissions of newly built ships, the ultra-long stroke of low-speed engines has become a trend (Lamas & Vidal 2012). With an ultralong stroke, the combustion speed of low-quality fuel oil is slow, and an ultra-long-stroke cylinder can prolong the expansion process, improve the combustion process, and reduce the fuel consumption rate (Fenghua 2014). The ultra-long-stroke diesel engine further creates fuel savings of 3.5–7% based on the original low fuel consumption. Previously, ultra-long strokes could not be achieved, limited by materials and manufacturing processes. However, in recent years, with the advancement of materials and processes, ultra-long strokes have been widely adopted as they have demonstrated superior competitiveness.
{"title":"Empirical Model of Uniflow Scavenging for Ultra-Long-Two-Stroke Marine Diesel Engines","authors":"Yingyuan Wang, J. Gu, Mingyang Yang, K. Deng, Lei Cui, Yuehua Qian","doi":"10.5957/josr.11210038","DOIUrl":"https://doi.org/10.5957/josr.11210038","url":null,"abstract":"\u0000 \u0000 Low-speed two-stroke diesel engines are widely employed in the marine industry, especially in tanks, owing to their advantages of fuel economy and reliability. However, with the emerging ultra-long-stroke trend, existing scavenging models, which are based on the configuration of cylinders with short strokes, are no longer applicable. In this study, we investigate the flow field and residual exhaust gas distribution in a cylinder using particle image velocimetry and computational fluid dynamics (CFD) simulations. The result shows a strong Burgers vortex structure upstream of the scavenger flow and dissipates gradually as it moves downstream. Furthermore, the scavenging process comprises three processes according to the detailed CFD analysis: displacement, mixing scavenging, and short circuit. Inspired by the results, a tailored empirical model of ultra-long-stroke uniflow scavenging comprising three sub-models is proposed. Specifically, a logarithmic relationship between the concentration level and scavenging deliver ratio is proposed to describe the mixing scavenging process. Finally, the model was validated against CFD results. The results demonstrate that the discrepancy in the scavenging efficiency curve predicted by this model and CFD is less than 1%, thereby demonstrating model reliability.\u0000 \u0000 \u0000 \u0000 Owing to the advantages of a large power range, high thermal efficiency, low fuel consumption rate, and good reliability, marine low-speed engines are widely used to provide power to civil ships (Heywood 1999). The market for low-speed engines is vast and is improving the performance of low-speed engines through research has great economic and environmental significance (Woodyard 2004). To meet the requirements of ship owners for lower fuel consumption and the IMO’s regulation of halving the greenhouse gas emissions of newly built ships, the ultra-long stroke of low-speed engines has become a trend (Lamas & Vidal 2012). With an ultralong stroke, the combustion speed of low-quality fuel oil is slow, and an ultra-long-stroke cylinder can prolong the expansion process, improve the combustion process, and reduce the fuel consumption rate (Fenghua 2014). The ultra-long-stroke diesel engine further creates fuel savings of 3.5–7% based on the original low fuel consumption. Previously, ultra-long strokes could not be achieved, limited by materials and manufacturing processes. However, in recent years, with the advancement of materials and processes, ultra-long strokes have been widely adopted as they have demonstrated superior competitiveness.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45627553","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}
Ship maneuvring simulators are a useful tool for the design of inland waterways and for training of skippers. The realism of the maneuvring prediction is a key success factor. In this paper, a 6 DOF (degrees of freedom) maneuvring model is presented which is able to predict the maneuvring behavior of push convoys in different, rigidly connected configurations (number of barges, draft of the barges, and position of the pusher) and for different water depths. The coefficients of this maneuvring model have been determined based on captive model tests and the realism is exemplified with a number of fast time simulation runs, including the turning on the spot of a convoy by means of uncoupled control of rudders and propellers. Final validations were performed during real-time simulation runs with experienced skippers. Knowledge on the maneuvring prediction of inland vessels is a key factor to determine the navigability of the waterways, especially when their water depth is limited (shallow water). The quality and accuracy of mathematical models require a continuous improvement. Push convoys operating in shallow water are intensively used performing long trips or elaborated maneuvers such as turning from a river into a harbor, turning on the spot, and astern sailing. An appropriate modeling of their maneuvring capacity requires a mathematical model able to operate in four quadrants (ahead or astern motion, combined with ahead or astern propulsion). In literature, papers which deal with the creation of reliable mathematical models for this type of inland vessels and their applications are rather scarce.
{"title":"Maneuvring Behavior of Push Convoys in Different Barge Configurations","authors":"G. Delefortrie, Jose Villagomez, J. Verwilligen","doi":"10.5957/josr.1220005","DOIUrl":"https://doi.org/10.5957/josr.1220005","url":null,"abstract":"\u0000 \u0000 Ship maneuvring simulators are a useful tool for the design of inland waterways and for training of skippers. The realism of the maneuvring prediction is a key success factor. In this paper, a 6 DOF (degrees of freedom) maneuvring model is presented which is able to predict the maneuvring behavior of push convoys in different, rigidly connected configurations (number of barges, draft of the barges, and position of the pusher) and for different water depths. The coefficients of this maneuvring model have been determined based on captive model tests and the realism is exemplified with a number of fast time simulation runs, including the turning on the spot of a convoy by means of uncoupled control of rudders and propellers. Final validations were performed during real-time simulation runs with experienced skippers.\u0000 \u0000 \u0000 \u0000 Knowledge on the maneuvring prediction of inland vessels is a key factor to determine the navigability of the waterways, especially when their water depth is limited (shallow water). The quality and accuracy of mathematical models require a continuous improvement. Push convoys operating in shallow water are intensively used performing long trips or elaborated maneuvers such as turning from a river into a harbor, turning on the spot, and astern sailing. An appropriate modeling of their maneuvring capacity requires a mathematical model able to operate in four quadrants (ahead or astern motion, combined with ahead or astern propulsion). In literature, papers which deal with the creation of reliable mathematical models for this type of inland vessels and their applications are rather scarce.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45344747","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}
Numerical prediction of ship maneuvering in waves was considered in this article. The wave drift loads, computed using the potential flow theory, were added into the mathematical modeling group (MMG) equations to account for the effect of waves on the ship maneuvering. Two numerical methods were tested for dealing with the coupled maneuvering-seakeeping problem, namely a time domain approach and a quasi-steady method. For the former approach, a time domain seakeeping computation was conducted that parallels to the maneuvering simulation. For the later one, it is assumed that at each time of the maneuvering process, the wave-ship interaction is in a time harmonic status and, therefore, the wave drift loads could be evaluated using a frequency domain computation. Turning maneuvers of the S-175 container ship in regular waves were numerically tested. The results of the quasi-steady method and the time domain approach show good agreements, which proved the validity of the quasi-steady assumption. The wave drift loads during the turning process were also presented, demonstrating the significant effect of the added resistance on the maneuvering prediction, in contrast to the less remarkable effects of the lateral wave drift force and the wave drift yaw moment. Ship maneuverability is typically predicted under calm water condition. This provides valuable information at the ship design stage. However, an actual seagoing ship usually maneuvers in waves. To reliably assess a ship’s navigation safety and total performance in a seaway, it is deemed important to understand the maneuvering behavior of a ship in waves. Indeed, ship maneuverability in waves has been increasingly investigated in recent years. Although the physical experiment is still regarded as the most reliable way to investigate ship maneuverability in waves, there are more and more studies providing practical mathematical models of ship maneuvering prediction. Generally, a mathematical model that is suitable for investigating the maneuvering of a ship in waves has to encapsulate the traditional theories of calm water maneuvering and forward-speed seakeeping.
{"title":"Comparative Study on Predicting Ship Maneuvering in Waves Using a Quasi-Steady Method and a Time Domain Approach","authors":"Wei Zhang, Jinlong Cheng, Xuanmin Li, G. He","doi":"10.5957/josr.06210021","DOIUrl":"https://doi.org/10.5957/josr.06210021","url":null,"abstract":"\u0000 \u0000 Numerical prediction of ship maneuvering in waves was considered in this article. The wave drift loads, computed using the potential flow theory, were added into the mathematical modeling group (MMG) equations to account for the effect of waves on the ship maneuvering. Two numerical methods were tested for dealing with the coupled maneuvering-seakeeping problem, namely a time domain approach and a quasi-steady method. For the former approach, a time domain seakeeping computation was conducted that parallels to the maneuvering simulation. For the later one, it is assumed that at each time of the maneuvering process, the wave-ship interaction is in a time harmonic status and, therefore, the wave drift loads could be evaluated using a frequency domain computation. Turning maneuvers of the S-175 container ship in regular waves were numerically tested. The results of the quasi-steady method and the time domain approach show good agreements, which proved the validity of the quasi-steady assumption. The wave drift loads during the turning process were also presented, demonstrating the significant effect of the added resistance on the maneuvering prediction, in contrast to the less remarkable effects of the lateral wave drift force and the wave drift yaw moment.\u0000 \u0000 \u0000 \u0000 Ship maneuverability is typically predicted under calm water condition. This provides valuable information at the ship design stage. However, an actual seagoing ship usually maneuvers in waves. To reliably assess a ship’s navigation safety and total performance in a seaway, it is deemed important to understand the maneuvering behavior of a ship in waves.\u0000 Indeed, ship maneuverability in waves has been increasingly investigated in recent years. Although the physical experiment is still regarded as the most reliable way to investigate ship maneuverability in waves, there are more and more studies providing practical mathematical models of ship maneuvering prediction. Generally, a mathematical model that is suitable for investigating the maneuvering of a ship in waves has to encapsulate the traditional theories of calm water maneuvering and forward-speed seakeeping.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46793929","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}
Of all the causes of accidents to ships, 14% pertains to damage due to ship equipment. Accordingly, the maritime industry is currently considering state-of-the-art maintenance and inspection processes, an example of which is condition-based maintenance (CBM). This is a strategy that hinges on the condition monitoring (CM) of assets. CM has proven to increase efficiency, reliability, profitability, and performance of vessel. To enable this maintenance strategy, sensors need to be installed along the most critical ship components and around the environment where these assets are operating through the application of Internet of Ships (IoS). IoS has demonstrated to be effective for collecting data in real time as well as performing diagnosis and prognosis to assess the current and future health of machinery to assist instant decision-making. The employment of IoS presents several challenges, an example of which is the imputation of missing values. Data imputation is a compelling preprocessing step, the aim of this is to estimate identified missing values to avoid underutilization of data. This data preparation step has gained popularity over the last few years due to its importance when dealing with Industrial Internet of Things (IIoT) sensor data. Although some articles presented new methodologies to impute missing values from sensor data of marine machinery based on machine learning methodologies, deep learning models have not yet been considered. For this reason, variational autoencoders for imputing missing values from sensor data of marine systems are analyzed in this article. To assess the performance of variational autoencoders as imputation methods, a comparative study is performed with widely implemented imputation techniques. Mean imputation, Forward Fill and Backward Fill, and k-Nearest Neighbors are considered. To that end, a case study on marine machinery system parameters obtained from sensors installed on a diesel generator of a tanker ship is performed. Results demonstrate the applicability of variational autoencoders when dealing with missing values of marine machinery systems sensor data, achieving a coefficient of determination of 0.99 when imputing missing values of the diesel generator power parameter.
{"title":"Analysis of Variational Autoencoders for Imputing Missing Values from Sensor Data of Marine Systems","authors":"C. Velasco-Gallego, I. Lazakis","doi":"10.5957/josr.09210032","DOIUrl":"https://doi.org/10.5957/josr.09210032","url":null,"abstract":"Of all the causes of accidents to ships, 14% pertains to damage due to ship equipment. Accordingly, the maritime industry is currently considering state-of-the-art maintenance and inspection processes, an example of which is condition-based maintenance (CBM). This is a strategy that hinges on the condition monitoring (CM) of assets. CM has proven to increase efficiency, reliability, profitability, and performance of vessel. To enable this maintenance strategy, sensors need to be installed along the most critical ship components and around the environment where these assets are operating through the application of Internet of Ships (IoS). IoS has demonstrated to be effective for collecting data in real time as well as performing diagnosis and prognosis to assess the current and future health of machinery to assist instant decision-making. The employment of IoS presents several challenges, an example of which is the imputation of missing values. Data imputation is a compelling preprocessing step, the aim of this is to estimate identified missing values to avoid underutilization of data. This data preparation step has gained popularity over the last few years due to its importance when dealing with Industrial Internet of Things (IIoT) sensor data. Although some articles presented new methodologies to impute missing values from sensor data of marine machinery based on machine learning methodologies, deep learning models have not yet been considered. For this reason, variational autoencoders for imputing missing values from sensor data of marine systems are analyzed in this article. To assess the performance of variational autoencoders as imputation methods, a comparative study is performed with widely implemented imputation techniques. Mean imputation, Forward Fill and Backward Fill, and k-Nearest Neighbors are considered. To that end, a case study on marine machinery system parameters obtained from sensors installed on a diesel generator of a tanker ship is performed. Results demonstrate the applicability of variational autoencoders when dealing with missing values of marine machinery systems sensor data, achieving a coefficient of determination of 0.99 when imputing missing values of the diesel generator power parameter.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48044322","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}
Muhammad Rabiul Islam, A. K. M. S. H. Barnil, Md. Shaidur Rahman, K. A. Hossain
Applicability of current Bangladesh inland vessels stability rule has been investigated for the local passenger vessels. Bangladesh inland vessel’s stability rule is exactly the same as international stability code (2008), despite of the different environmental load in navigational routes. The restricted waterways limit the dimension of the vessels. It has been found that domestic passenger vessels have changed their dimensions considerably from the year 1974 to 2009. But analysis shows, still most of the domestic passenger vessels exceed the dimensional ratio range that is specified in both the righting lever-based criteria and weather criterion of international code. The part of the weather criterion, specifically estimation method for the angle of roll due to wind and wave action has been studied in details. Different nationals have adopted values of governing parameters for extended range of vessel dimensions, which can also successfully cover all the Bangladesh domestic passenger vessels. As per the code 2008, for ships with values outside of the addressed range, the angle of roll may be determined with model experiments of a subject ship as alternative weather criterion. Bangladesh is still lacking both in facility and infrastructure for carrying model tests. This study shows that computer simulation can be used in exchange of experimental setup where the simulation result can be validated by Parameter Identification Technique, which is described as an alternative approach in the interim guideline of International Maritime Organization (IMO). Passenger vessel accident is a persistent phenomenon in Bangladesh inland waterways. Thousands of people have passed away due to these catastrophic incidents. The major two modes of failure that are responsible for accidents in waterways are identified as structural failure and stability failure (Islam et al. 2015a). Structural failure like collision also leads to stability failure (Damage Stability). Iqbal et al. (2008a, 2008b) analyzed the Bangladesh inland passenger vessels accident data of 25 years and found that in 49% cases, the failure was due to lose of intact stability. Raiyan et al. (2017) have done event tree analysis of marine accidents in Bangladesh taking initial condition as overloading. Literature study (Awal 2006; Awal et al. 2007; Awal et al. 2014; Islam et al. 2015b; Rahman 2017) shows that researchers have proposed many general recommendations from different point of view to prevent the passenger vessel accidents. But still now, no attempt has been made to analyze the currently applicable statutory rules for ensuring the safety in inland waterways, which is mainly Bangladesh Inland Vessels Stability Rule including Weather Criterion (Zulfikar 2005). Stability rules of inland vessels are to be governed by standard localized condition of the subjected parameters. The socioeconomic condition, local environment, as well as infrastructural development like availability of model
对孟加拉国现行内河船舶稳定性规则在国内客船中的适用性进行了研究。孟加拉国内河船舶的稳定规则与国际稳定规则(2008)完全相同，尽管航行路线的环境负荷不同。受限制的水道限制了船只的尺寸。研究发现，从1974年到2009年，国内客船的尺寸发生了很大变化。但分析表明，国内客船仍有大部分超出了国际规范中基于撑杆的标准和气象标准所规定的尺寸比范围。对天气判据部分，特别是风浪作用下横摇角的估计方法进行了详细的研究。不同的国家采用了船舶尺寸范围扩大的控制参数值，这也可以成功地涵盖所有孟加拉国国内客船。根据2008年规范，对于数值不在指定范围内的船舶，可以用目标船舶的模型试验确定横摇角，作为备选的天气判据。孟加拉国仍然缺乏进行模型试验的设施和基础设施。本研究表明，计算机模拟可以用于交换实验装置，模拟结果可以通过参数识别技术进行验证，这是国际海事组织(IMO)临时指南中描述的一种替代方法。客船事故是孟加拉国内河航道持续存在的现象。成千上万的人死于这些灾难性的事件。导致水道事故的两种主要失效模式被确定为结构失效和稳定性失效(Islam et al. 2015)。碰撞等结构破坏也会导致稳定性破坏(Damage stability)。Iqbal et al. (2008a, 2008b)分析了孟加拉国内陆客船25年的事故数据，发现49%的事故是由于失去完整的稳定性造成的。Raiyan等人(2017)以超载为初始条件对孟加拉国的海上事故进行了事件树分析。文献研究(Awal 2006;Awal et al. 2007;Awal et al. 2014;Islam等，2015b;Rahman 2017)表明，研究人员从不同的角度提出了许多一般性建议，以防止客船事故。但是，目前还没有尝试分析目前适用的法律规则，以确保内河航道的安全，主要是孟加拉国内河船舶稳定规则，包括天气标准(Zulfikar 2005)。内河船舶的稳定规律是由受测参数的标准局部条件所控制的。需要考虑社会经济条件、当地环境以及基础设施发展，如模型试验设施的可用性，以便顺利和适当地应用稳定性规则，从而确保当地船只的安全。这表明，有关国家在研究和分析方面的个别努力对制定切实可行的内河船舶稳定规则具有重要意义。
{"title":"Applicability of Current Statutory Rules for Stability Requirements of Bangladesh Inland Passenger Vessels","authors":"Muhammad Rabiul Islam, A. K. M. S. H. Barnil, Md. Shaidur Rahman, K. A. Hossain","doi":"10.5957/josr.12210049","DOIUrl":"https://doi.org/10.5957/josr.12210049","url":null,"abstract":"\u0000 \u0000 Applicability of current Bangladesh inland vessels stability rule has been investigated for the local passenger vessels. Bangladesh inland vessel’s stability rule is exactly the same as international stability code (2008), despite of the different environmental load in navigational routes. The restricted waterways limit the dimension of the vessels. It has been found that domestic passenger vessels have changed their dimensions considerably from the year 1974 to 2009. But analysis shows, still most of the domestic passenger vessels exceed the dimensional ratio range that is specified in both the righting lever-based criteria and weather criterion of international code. The part of the weather criterion, specifically estimation method for the angle of roll due to wind and wave action has been studied in details. Different nationals have adopted values of governing parameters for extended range of vessel dimensions, which can also successfully cover all the Bangladesh domestic passenger vessels. As per the code 2008, for ships with values outside of the addressed range, the angle of roll may be determined with model experiments of a subject ship as alternative weather criterion. Bangladesh is still lacking both in facility and infrastructure for carrying model tests. This study shows that computer simulation can be used in exchange of experimental setup where the simulation result can be validated by Parameter Identification Technique, which is described as an alternative approach in the interim guideline of International Maritime Organization (IMO).\u0000 \u0000 \u0000 \u0000 Passenger vessel accident is a persistent phenomenon in Bangladesh inland waterways. Thousands of people have passed away due to these catastrophic incidents. The major two modes of failure that are responsible for accidents in waterways are identified as structural failure and stability failure (Islam et al. 2015a). Structural failure like collision also leads to stability failure (Damage Stability). Iqbal et al. (2008a, 2008b) analyzed the Bangladesh inland passenger vessels accident data of 25 years and found that in 49% cases, the failure was due to lose of intact stability. Raiyan et al. (2017) have done event tree analysis of marine accidents in Bangladesh taking initial condition as overloading. Literature study (Awal 2006; Awal et al. 2007; Awal et al. 2014; Islam et al. 2015b; Rahman 2017) shows that researchers have proposed many general recommendations from different point of view to prevent the passenger vessel accidents. But still now, no attempt has been made to analyze the currently applicable statutory rules for ensuring the safety in inland waterways, which is mainly Bangladesh Inland Vessels Stability Rule including Weather Criterion (Zulfikar 2005). Stability rules of inland vessels are to be governed by standard localized condition of the subjected parameters. The socioeconomic condition, local environment, as well as infrastructural development like availability of model","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45868294","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 : 2022-06-07DOI: 10.5957/jsr.1969.13.4.276
S. Chuang
A general expression for the pressure distribution on a cone penetrating the water surface is derived from the similar procedure developed by Wagner for a wedge. The effect of trapped air between the falling body and the water is ignored for this investigation. The pressure distributions, velocity potentials, stream functions, and piled-up water phenomenon are summarized and compared with those for the wedge. Wagner provided a theoretical analysis on the slamming of a wedge [1,2,3].3 His approach was to approximate the wedge as an equivalent flat plate provided that the wedge had a small deadrise angle. By means of the velocity potential technique and the Bernoulli equation, he derived equations for determining the pressure distributions on the impact surface of the wedge. A cone piercing the water surface has been studied experimentally by Watanabe [4] and theoretically by Shiffman and Spencer [5]. However, their work provided only the total force acting on the impact surface of a cone. The purpose of the present work is therefore to determine theoretically the slamming pressure distribution of a cone. The similar approaches developed by Wagner for his wedge equations are used for this investigation.
{"title":"Theoretical Investigations on Slamming of Cone-Shaped Bodies","authors":"S. Chuang","doi":"10.5957/jsr.1969.13.4.276","DOIUrl":"https://doi.org/10.5957/jsr.1969.13.4.276","url":null,"abstract":"A general expression for the pressure distribution on a cone penetrating the water surface is derived from the similar procedure developed by Wagner for a wedge. The effect of trapped air between the falling body and the water is ignored for this investigation. The pressure distributions, velocity potentials, stream functions, and piled-up water phenomenon are summarized and compared with those for the wedge.\u0000 Wagner provided a theoretical analysis on the slamming of a wedge [1,2,3].3 His approach was to approximate the wedge as an equivalent flat plate provided that the wedge had a small deadrise angle. By means of the velocity potential technique and the Bernoulli equation, he derived equations for determining the pressure distributions on the impact surface of the wedge.\u0000 A cone piercing the water surface has been studied experimentally by Watanabe [4] and theoretically by Shiffman and Spencer [5]. However, their work provided only the total force acting on the impact surface of a cone. The purpose of the present work is therefore to determine theoretically the slamming pressure distribution of a cone. The similar approaches developed by Wagner for his wedge equations are used for this investigation.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48284185","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}
Hull optimization is an important aspect of ship design to improve safety and economic-technical efficiency for ships. This problem has been studied for a long time and has achieved many significant results, but in practical applications, there are still some contents that need to be improved such as the presentation and transformation of the existing hulls, an optimal mathematical model suitable for a specific type of ship, or method for solving the objective function, etc. On that basis, in this paper, a method for optimizing the hull form of fishing vessels is presented, including algorithms using interpolating cubic spline to generate the existing hulls that pass exactly through the given offsets and are constructed in a format to use both Computational Fluid Dynamics (CFD) analysis in resistance prediction and Lackenby method in hull form transformation, a suitable mathematical model for hull optimization problem of fishing vessels, an effective solver based on a combination of CFD, Kriging surrogate models, and traditional optimization techniques. In addition, solutions for improving the accuracy of CFD-based resistance predictions are also presented based on ensuring the accuracy of the 3D hull models and determining the suitable input parameters used for CFD simulations. This study was applied to optimize the hull form of a Vietnamese traditional wooden fishing vessel, symbol MH076, and obtained results that are consistent with the theoretical and practical trends, with the deviations of CFD-based resistance values and corresponding model test data are within the range of 63% and the reduction in total resistance or required power at design operating is around 8.81%.
{"title":"A Method for Optimizing the Hull Form of Fishing Vessels","authors":"T. G. Tran, Ha Vu Nguyen, Q. Huynh","doi":"10.5957/josr.05210017","DOIUrl":"https://doi.org/10.5957/josr.05210017","url":null,"abstract":"Hull optimization is an important aspect of ship design to improve safety and economic-technical efficiency for ships. This problem has been studied for a long time and has achieved many significant results, but in practical applications, there are still some contents that need to be improved such as the presentation and transformation of the existing hulls, an optimal mathematical model suitable for a specific type of ship, or method for solving the objective function, etc. On that basis, in this paper, a method for optimizing the hull form of fishing vessels is presented, including algorithms using interpolating cubic spline to generate the existing hulls that pass exactly through the given offsets and are constructed in a format to use both Computational Fluid Dynamics (CFD) analysis in resistance prediction and Lackenby method in hull form transformation, a suitable mathematical model for hull optimization problem of fishing vessels, an effective solver based on a combination of CFD, Kriging surrogate models, and traditional optimization techniques. In addition, solutions for improving the accuracy of CFD-based resistance predictions are also presented based on ensuring the accuracy of the 3D hull models and determining the suitable input parameters used for CFD simulations. This study was applied to optimize the hull form of a Vietnamese traditional wooden fishing vessel, symbol MH076, and obtained results that are consistent with the theoretical and practical trends, with the deviations of CFD-based resistance values and corresponding model test data are within the range of 63% and the reduction in total resistance or required power at design operating is around 8.81%.","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49065262","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}
Risk assessment of offshore oil-related platforms such as the floating production storage and offloading system (FPSO) is extremely important. In earthquakes prone to target sea areas, earthquakes should be considered as one of the important external forces that cause severe damage. In such risk assessments, for estimating the appearance frequency of seismic energy, the complementary cumulative distribution function (CCDF) of seismic energy of a considered area is usually based on the Gutenberg–Richter law. Furthermore, it is important to estimate the CCDF of the leak hole diameter when estimating the damage caused by an oil spill accident in an offshore oil-related platform. Some ship classification societies recommend using a formula based on the power law distribution as used in those processes. However, the power law distribution has a drawback in that, i.e., it is essentially impossible to accurately estimate the CCDF over the entire domain of the random variables. The authors have developed an enhanced power law distribution function that eliminates such defects in the power law distribution function and some practical methods for estimating its parameters. In this study, the developed function is applied to the CCDFs of the seismic energy and leak hole diameter. The results demonstrate that the function fits the existing data with sufficient accuracy. Therefore, the new function introduced here can be well used in the frequency analysis of the risk assessment of offshore oil-related platforms. In the risk assessment of offshore oil-related platforms like floating production storage and offloading system (FPSO), it is necessary to estimate probabilistic characteristics of external forces against them. Earthquakes are a major external force. Furthermore, it is necessary to estimate the damage when an external force is applied. The frequency of external forces, such as earthquakes, is low, but the damage is extensive. However, damage to offshore oil-related platforms is caused by not only these external forces, but also oil leaks resulting from some factors, such as operation errors and corrosion, that may cause accidents such as fire and explosion. Therefore, it is also essential to estimate the probabilistic characteristics of such damage for the risk assessment of offshore oil-related platforms.
{"title":"A New Function for Frequency Analysis in the Risk Assessment of Offshore Oil-Related Platforms","authors":"F. Kaneko, T. Yuzui","doi":"10.5957/josr.04210009","DOIUrl":"https://doi.org/10.5957/josr.04210009","url":null,"abstract":"Risk assessment of offshore oil-related platforms such as the floating production storage and offloading system (FPSO) is extremely important. In earthquakes prone to target sea areas, earthquakes should be considered as one of the important external forces that cause severe damage. In such risk assessments, for estimating the appearance frequency of seismic energy, the complementary cumulative distribution function (CCDF) of seismic energy of a considered area is usually based on the Gutenberg–Richter law. Furthermore, it is important to estimate the CCDF of the leak hole diameter when estimating the damage caused by an oil spill accident in an offshore oil-related platform. Some ship classification societies recommend using a formula based on the power law distribution as used in those processes. However, the power law distribution has a drawback in that, i.e., it is essentially impossible to accurately estimate the CCDF over the entire domain of the random variables. The authors have developed an enhanced power law distribution function that eliminates such defects in the power law distribution function and some practical methods for estimating its parameters. In this study, the developed function is applied to the CCDFs of the seismic energy and leak hole diameter. The results demonstrate that the function fits the existing data with sufficient accuracy. Therefore, the new function introduced here can be well used in the frequency analysis of the risk assessment of offshore oil-related platforms.\u0000 \u0000 \u0000 In the risk assessment of offshore oil-related platforms like floating production storage and offloading system (FPSO), it is necessary to estimate probabilistic characteristics of external forces against them. Earthquakes are a major external force. Furthermore, it is necessary to estimate the damage when an external force is applied. The frequency of external forces, such as earthquakes, is low, but the damage is extensive. However, damage to offshore oil-related platforms is caused by not only these external forces, but also oil leaks resulting from some factors, such as operation errors and corrosion, that may cause accidents such as fire and explosion. Therefore, it is also essential to estimate the probabilistic characteristics of such damage for the risk assessment of offshore oil-related platforms.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45056402","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}
The main purpose of this study is to improve the level of marine safety management. The safety checklist and reverse management model are used to check and measure marine safety. The results indicate that the test results are M1 = 88.705 and M2 = 95.164 respectively (M2 > M1), suggesting that the reverse management safety model has played a positive role in the actual operation. It has been concluded the reverse management model can improve the safety level of marine engineering management, but not all factors are significantly improved. This paper summarizes the working principle of reverse management, which is feasible in practical application. In recent years, fishing vessel accidents occur frequently in China (Jiangqun 2008; Huadang 2011; Yuanjiao 2015). For example, there are nearly 20,000 fishing boats in Liaoning Province. Most of them are equipped with a four-wheel hydraulic winder favored by the majority of fishermen for its advantages of large pulling force and fast net pulling speed. However, there are also serious safety risks, such as finger breaking in light cases and arm breaking in heavy cases (Dage et al. 2004). Most of the wooden fishing boats above 60 hp in Hebei Province have purchased four-wheel winders and eliminated the original two-wheel ones. Through actual case, it has played a role in increasing work efficiency and improving economic benefits. However, we can also see that the number of casualties of fishing boat crew has increased significantly. According to preliminary statistics, there were more than 120 net gear accidents in 2000 in the whole province, seriously injuring more than 30 crew members, which seriously affected the fishery safety situation (Qiang 2002). These situations are closely related to ship automation.
{"title":"Design and Test of Marine Engine Safety Management Model Based on “Reverse Management”","authors":"Xue Yingchun, Chen Guoping","doi":"10.5957/josr.03210005","DOIUrl":"https://doi.org/10.5957/josr.03210005","url":null,"abstract":"The main purpose of this study is to improve the level of marine safety management. The safety checklist and reverse management model are used to check and measure marine safety. The results indicate that the test results are M1 = 88.705 and M2 = 95.164 respectively (M2 > M1), suggesting that the reverse management safety model has played a positive role in the actual operation. It has been concluded the reverse management model can improve the safety level of marine engineering management, but not all factors are significantly improved. This paper summarizes the working principle of reverse management, which is feasible in practical application.\u0000 \u0000 \u0000 In recent years, fishing vessel accidents occur frequently in China (Jiangqun 2008; Huadang 2011; Yuanjiao 2015). For example, there are nearly 20,000 fishing boats in Liaoning Province. Most of them are equipped with a four-wheel hydraulic winder favored by the majority of fishermen for its advantages of large pulling force and fast net pulling speed. However, there are also serious safety risks, such as finger breaking in light cases and arm breaking in heavy cases (Dage et al. 2004). Most of the wooden fishing boats above 60 hp in Hebei Province have purchased four-wheel winders and eliminated the original two-wheel ones. Through actual case, it has played a role in increasing work efficiency and improving economic benefits. However, we can also see that the number of casualties of fishing boat crew has increased significantly. According to preliminary statistics, there were more than 120 net gear accidents in 2000 in the whole province, seriously injuring more than 30 crew members, which seriously affected the fishery safety situation (Qiang 2002). These situations are closely related to ship automation.\u0000","PeriodicalId":50052,"journal":{"name":"Journal of Ship Research","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48356126","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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