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In this study, a collision risk model was developed, based on gas model theory and Pedersen's collision and grounding mechanics. Busan north port was chosen as the area of assessment and, was divided into equal cells. Geometrical collision risk, both ship-ship and ship-structure, within each cell was analyzed following a probabilistic quantification. Moreover, bathymetry data of the port waters were analyzed to assess grounding risks. Results were plotted on Google EarthTM to identify the highest risk point and region within the area of assessment to aid safe maneuvering of vessels.
With the recent trends and advancements in maritime world, emergence of new ships is inescapable and consequently, maritime traffic density has continued to expand. Increased number of ships, as well as bigger ships in narrow passages attribute to higher volumes of traffic in already congested waterways and particularly, in port areas. This, in turn, makes ship maneuvering more difficult and complicated. Moreover, higher maritime traffic can increase the risk of collision accidents with unfavorable consequences. Although some major technological advancements such as ECDIS (Electronic Chart Display and Information System), ARPA (Automatic Radar Plotting Aids), GNSS (Global Navigation Satellite System) and GMDSS (Global Maritime Distress & Safety System) are successfully integrated with navigation, port and harbor areas are still more susceptible to collision accidents. Thus, evaluating the risk of collision has become an integral part in maneuvering supporting systems to improve safety in navigation by decreasing the risk of collision.
Collision risk in navigation is often misread due to the rarity of disastrous, individual accidents. Ylitalo (2010) discovered that the probability of an accident in a particular area would not be zero, although there is less or no records of previous incidents. Even though the probability of a direct ship-ship collision is very small, a minor incident can have unfavorable consequences, which can lead to loss of property as well as life at sea. Therefore, all risks in navigation have to be taken seriously. Identifying the risk areas, therefore, is vital to minimize and to avoid accidents. Once the risk areas are clearly identified, measures such as emergency planning can be taken for safe maneuvering of ships.
Xu, Ning ( National Marine Environmental Monitoring Center) | Yuan, Shuai ( National Marine Environmental Monitoring Center) | Ma, Yuxian ( National Marine Environmental Monitoring Center) | Zhang, Dayong (School of Ocean Engineering and Technology, Dalian University of Technology) | Chen, Yuan ( National Marine Environmental Monitoring Center) | Liu, Xueqin ( National Marine Environmental Monitoring Center) | Shi, Wenqi ( National Marine Environmental Monitoring Center) | Song, Lina ( National Marine Environmental Monitoring Center)
Physical mechanisms of typical risk sources and classification analysis of risk modes for sea ice disasters on marine engineering structures are explored in the study. Based on 22 accidents and 14 potential risk cases, the risk sources of sea ice disasters on marine engineering structures are classified and 6 sea ice disaster sources (extreme ice force, dynamic ice force, ice jamming, etc.) are proposed. The structural failure modes and main influencing factors of sea ice disasters on marine engineering structures are demonstrated. Based on the physical mechanisms of sea ice failure and removal, risk sources and failure modes are summarized for three dominant kinds of marine engineering projects in China (platform, port, and nuclear power facilities). The risk mode analysis of sea ice disasters in the study provides the technical support for marine engineering structures in the design stage, operation stage, and risk assessment and emergency stage.
The icing phenomenon occurs every year in the Bohai Sea and the northern Yellow Sea, which are the ice-covered sea area with the lowest latitude in the northern hemisphere in China. International studies on sea ice disasters began in the early last century (Sanderson, 1988) and China has also carried out relevant studies for more than forty years (Bao, 1991; Yang, et al, 1993; Sun, et al, 2011). The sea ice disasters are the third largest marine disasters in China. Since the 20th century, more than 20 sea ice disasters have occurred in the Bohai Sea, including 5 severe ice disasters respectively in 1936, 1947, 1957, 1969, and 1977. According to the statistical data of sea ice disasters (Yang, et al, 1993), medium and severe sea ice disasters in the whole Bohai Sea and Yellow Sea occurred once approximately every 5 to 6 years and sea ice disasters in local sea areas occurred almost every year. The sea ice disasters have attracted widespread attention since the No. 2 offshore platform was overthrown by sea ice in 1969. In the sea ice disaster in early 2010, some ports and navigation channels were frozen and a large number of aquaculture products died, thus resulting in a direct economic loss of nearly ¥ 6.4 billion (Zou et al. 2011; SOA, 2010).
Xie, Fengze (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Zhang, Guanyu (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Wan, Decheng (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University)
In the field of ocean engineering, the phenomena of fluid-structure interaction (FSI) often occur, which has destructive effect on offshore structures. In order to prolong the service life of structures, it is necessary to evaluate the dynamic responses of structures under the influence of violent flows. In this present work, an in-house solver MPSDEM-SJTU is developed based on the improved moving particle semi-implicit (MPS) method and discrete element method (DEM). The MPS method is used to simulate the movement of fluid while the DEM is employed to analyze the dynamic responses of structures. For the coupling algorithm, the pressure carried by MPS particles is passed to the DEM particles. In turn, the velocity and displacement information will be transferred from solid domain to fluid domain. The solver is validated by comparison with benchmark tests, such as the flood discharge with an elastic gate and dam-break with an elastic baffle. The numerical results show good agreement with experimental data and other numerical results.
The fluid-structure interaction problems with violent free surface flows widely occur in ocean engineering field, such as sloshing in the tank with elastic baffles (Zhang et al., 2016), solitary waves impacting on the horizontal plate (Rao and Wan, 2018) and dam-break flows interacting with elastic wall (Zhang and Wan, 2018). It is difficult for traditional grid-based methods to capture the complex free surface flows, especially for fragmentations and splashing. Besides, the structures with large deformation is also hard to handle, because the distorted grids may affect the accuracy of simulation and the remeshing is time-consuming. In the contrast, it is easy for particle methods to overcome these difficulties. There are no fixed topological relations among lagrangian particles and the information exchange isn't restricted to specific nodes. Therefore, the particle methods have the potential to be applied to severe FSI problems.
Wang, Wentao (Shanghai Jiao Tong University / China Ship Scientific Research Center) | Qiu, Gengyao (China Ship Scientific Research Center) | Wang, Jianhua (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Wan, Decheng (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University)
Ship bow wave breaking phenomenon is still a challenge for CFD simulation, due to unsteady mixture flow and the lack of detailed experimental validation data. As a new wave breaking study case, a scaled KRISO container ship (KCS) model of 1/52.6667 is selected. To determine the appropriate detailed wave breaking measurement case conditions for future CFD validation, experimental and computational investigations are conducted with trim and sinkage variation. The trim and sinkage have significant effects on wave breaking phenomenon. Spilling and plunging wave breaking are observed.
Wave breaking is a quite common flow phenomenon at sea for ships. The breaking waves around ship bow region can produce sprays, mixture of air – water mixture flow and will extend to the far field of ship's downstream, which will affect the performance of the hull & propulsion systems and increase the ship wake signatures.
The 3D breaking wave and the flow field due to the breaking waves are quite challenging for CFD solvers. Wilson et al. (2006) investigated the breaking waves for the high-speed transom stern ship (R/V Athena I) by using the URANS solver in CFDSHIP-IOWA. One low
Ge, Chang (School of Transportation, Southeast University) | Xu, Sudong (School of Transportation, Southeast University) | Zhong, Yingmeng (School of Transportation, Southeast University) | Xie, Wen (School of Transportation, Southeast University) | Su, Guanhong (School of Transportation, Southeast University) | Xiong, Qiwei (School of Transportation, Southeast University)
This paper studies the application of BIM Technology in the whole life which contains "preliminary planning", "design and planning", "construction" as well as "operation and demolition" of waterway engineering project. According to BIM Revit software, we established the virtual model of ship lock channel, and integrated the engineering construction information with Autodesk software series to build a complete application framework process. The application of BIM Technology in the whole life cycle could promote the efficiency of multi-party collaborative work of engineering projects, and improves the level of informatization and construction management. Therefore, this study has a application prospect in the water transport industry.
According to the definition in "JTS / T198-1-2019 unified standard" for application of information model of water transport engineering, the Whole Life Cycle of the project is the general term of all stages of water transport engineering from planned construction to use termination, including planning, design, construction, operation and maintenance, demolition and other stages. At present, the Whole Life Cycle of the project is under construction management by different departments and units, which is lack of unified standards. The information transmission is not convenient (Zou, 2018). Therefore, CCCC and other design institutes planned to establish the information model of water transport engineering in water transport engineering. It is the digital expression of physical and functional characteristics of water transport engineering, to provide information support for various decisions in the Whole Life Cycle of the project. In order to solve this problem, this project studied the application of BIM Technology of water transport engineering, established the framework of the Whole Life Cycle application platform, provided information-based data model, and realized the transmission of visual and parametric model.
So that the water transport engineering model can be shared and applied in all stages of the project, among all disciplines and interested parties.
Free surface flow around a surface-piercing flat plate operating at incidence is a suitable research subject for marine hydrodynamics, because it includes typical flow features found in marine hydrodynamics such as vortex generation, flow separation, and free surface flows. For those reasons, it is selected by the ITTC committee as a benchmarking case for Stereo PIV(SPIV) test. In this paper, flow past a surface-piercing flat plate is studied by computational fluid dynamics (CFD) simulations. The incident angle is 20 degree and the current velocity is 0.4 m/s. Unsteady Reynolds-averaged Navier-Stokes (URANS) simulation is carried out and compared with the existing experimental data. The hydrodynamic forces on the flat plate, velocity profile in the wake regions are presented and analyzed. In addition, the vortical structures are identified and visualized by the Liutex/Rortex method.
Flow around surface-piercing structures involves interactions between current, wave and body and is of importance for ship and ocean engineering. Wave-induced pressure gradient will affect the boundary layer around the submerged body and vice versa, boundary layer will affect the waves of first order forces and moments (Metcalf et al., 2006). On the other hand, the submerged structures are commonly with truncated free end at the bottom and the tip vortices shed from bottom will interact with free surface (Briggs et al., 2019).
Similar physical problems have been extensively studied. Stern et al. (1987) studied the effects of waves on the boundary layer of a surfacepiercing flat plate with an upstream horizontal foil with variable depth of submergence used for generation of Stokes waves in a towing tank for a range of wave steepness and average Re=1.64×106. They observed wedge shaped, broken and turbulent separation region on the free surface.
Metcalf et al. (2006) experimentally investigated the unsteady freesurface wave-induced boundary-layer separation for a surface-piercing NACA 0024 foil in a towing tank at three different Froude numbers, 0.19, 0.37 and 0.55 and three Reynolds numbers, 0.822, 1.52 and 2.26×106. They provided mean and unsteady far-field wave elevations, mean and unsteady foil-surface pressures and analyzed the frequency components of shear layer, Karman shedding, and flapping instabilities, respectively. However, no PIV measurement is conducted in their study.
Chen, Weimin (Marine technology division, Shanghai Ship and Shipping Research Institute) | Zhang, Li (Marine technology division, Shanghai Ship and Shipping Research Institute) | Chen, Jianting (Marine technology division, Shanghai Ship and Shipping Research Institute)
Following the ITTC (2017) recommended procedures of the ship model resistance tests and uncertainty analysis, the error sources in the test process were analyzed. The influence of these error sources on the test results are determined according to the propagation principle of uncertainty. The error components are divided into type A uncertainty for random error during the model tests and type B uncertainty for other error sources. Repeat-run tests were carried out on a single-screw benchmark ship model equipped with and without rudder at 7 speeds. According to the guidelines of model tests, these test results are converted to a unified nominal water temperature at 15°C. The analysis results show that: 1) the average resistance results of the ship model without rudder are lower than the average resistance of ship model with rudder, the differences are between 0.499% to 0.929%. 2) At 95% confidence level(k=2), when the ship is without rudder, the expanded uncertainty of the average resistance at different speeds is between 0.316% and 0.554%. When the ship is with rudder, the expanded uncertainty of the average resistance at different speeds is between 0.311% and 0.508%. 3) Among the uncertainty components, the type A uncertainty of the model tests and the type B uncertainty of the carriage speed account for a large proportion of the uncertainty component. Finally, this paper further puts forward the measures to reduce the uncertainty of the model tests.
The accuracy of the ship model test has a direct and important impact on the performance prediction of the full-scale ship, each towing tank member is also taking measures to improve the test accuracy, such as improving the instrument measurement accuracy, increasing the period of measurement time, improving the standardization and so on.
Uncertainty analysis is a method to quantify errors, which is based on the theoretical true value and measures the probability level of the test results within a certain range of errors(Coleman, 1999; Coleman, 2018). In the uncertainty analysis steps of ship model test, the test process should be combed firstly. Then the influence degree of each variable, namely sensitivity, is determined based on the DRE (Data Reduction Equation). Finally, the uncertainty of the variable and its sensitivity are combined, and the uncertainty of ship model test can be calculated.
Liu, Yihua (School of Naval Architecture & Ocean Engineering, Dalian University of Technology ) | Li, Hongxia (School of Naval Architecture & Ocean Engineering, Dalian University of Technology ) | Huang, Yi (School of Naval Architecture & Ocean Engineering, Dalian University of Technology )
In this paper, the new concept polar ocean nuclear energy platform was introduced and the influence of the moonpool on its towing resistance was studied. STAR-CCM + was used to calculate the towing resistance of the nuclear power platform at different towing speeds when the moonpool was at both open and closed. It can be found that towing resistance increased obviously with the increase of towing speed. The existence of the moonpool tends to disorder the flow field around the platform, which will cause a 20%-30% increase on the nuclear power platform's towing resistance. The research on the mechanism of increasing the resistance of the lunar moonpool can provide some guidances for the design of nuclear energy platform in the future.
In recent years, as the global warming continues unabated, the arctic sea ice gradually melts, and regular navigable waters appear in summer. It is highly possible that the arctic ocean will be ice-free in summer of 2050 (LI Z.F., 2019). The ice-free state of the arctic in summer will bring certain economic benefits to the development of the global economy: if the arctic shipping route is used, the sailing time and energy consumption of the route from China to the northern Europe or the Baltic sea will be 1/3 less than those of the traditional route. If the destination is within the Arctic Circle, the sailing time and energy consumption will be 1/2 less (CAI M.J., 2019). In addition, the arctic is rich in natural resources, including 13% of the world's proven oil reserves and 30% of the world's natural gas reserves. If the polar natural resources are to be exploited, the problem of power supply needs to be solved urgently. The ecological environment of the arctic region is fragile (LIU D.H., 2019), and it has high requirements for environmental protection of engineering equipment. The offshore nuclear power platform can provide sufficient, stable and environmentally friendly power (LI X., 2019), which is the best choice for the development of power supply equipment in the polar region and has a broad application prospect.
Zhang, Nini (Waterway and Coastal Engineering, School of Transportation, Southeast University ) | Yin, Kai (Waterway and Coastal Engineering, School of Transportation, Southeast University ) | Xu, Sudong (Waterway and Coastal Engineering, School of Transportation, Southeast University ) | Yang, Yanhua (Waterway and Coastal Engineering, School of Transportation, Southeast University )
To investigate the influences of 12.5m deep-water channel project and sea level rise (SLR) on the hydrodynamic factors in Fujiangsha waterway of the Yangtze River, a two-dimensional Delft3D-FLOW hydrodynamic model was established. This model performed well to reproduce the tide level and flow velocity. Simulations were then conducted by putting the dams into the verified numerical model and adding 1m water depth to the open sea. Results demonstrated that both regulation project and SLR have significant influences on the hydrodynamic factors in Fujiangsha waterway. This study will be beneficial to the management and planning of the waterway.
The construction project of 12.5m deep water channel of the Yangtze River below Nanjing city is one of the major projects with the largest investment scale and the most complicated technology in China's inland water transportation during the 12th Five Year Plan period. The first-stage construction project covers Taicang to Nantong, which was completed in December 2015. And the second phase from Nantong to Nanjing has been fulfilled in May 2019. The Fujiangsha waterway section presents the pattern of "two levels of split and compresence of three navigable branches" on the plane (Qu and Ma, 2019). Because of its complex terrain conditions and the severe evolution of the shoals and troughs, it is one of the key waterway sections in the project. Relying on the implementation of the engineering arrangement, the hydrodynamic of the Fujiangsha waterway section has changed a lot. Therefore, it is instrumental in the planning and development of Fujiangsha waterway through analyzing the hydrodynamic in the field and evaluating the effect of the regulation project.
As Fujiangsha waterway is a typical tidal reach, its regulation and management need to consider the influence of sea level rise (SLR). SLR is a critical and uncertain climate change risk. It is a serious consequence of ongoing climate change, and its confident projection into the remainder of this century (and beyond) is important for mitigating and managing risk in the coastal zone. It will not only increase the probability of occurrence of storm surge, huge wave, saltwater tide and soil salinization, but also increase the average sea level and characteristic tide level together with enhancing the wave action near the shore as well as intensify the impact of disasters. Therefore, it is of great significance for its risk management and future planning to analyze the hydrodynamic changes in Fujiangsha waterway section caused by SLR.
KBR announced that its joint venture with SOCAR, who is undertaking the engineering design phase of the Azeri Central East (ACE) platform, is now nearing completion. The ACE platform is the first of its kind to be designed through all phases, from concept to front-end engineering design and detailed design, to fully use KBR’s digital twin technology. The benefits of the digital twin continue to be used as the ACE platform moves into fabrication and commissioning, which is being undertaken in Azerbaijan. Digital twin technology creates a platform for all involved in the process to access all project information from anywhere in the world through all phases. The technology allows users to view procurement status and materials availability.