Numerical analysis of cavitating propeller and pressure fluctuation on ship stern using a simple surface panel method “SQCM”

This paper presents a calculation method for the pressure fluctuation induced by a cavitating propeller. This method consists of two steps: the first step is the calculation of propeller sheet cavitation, and the second step is the calculation of pressure fluctuation on the ship stern. It is for practicality that we divide the method into two steps but do not calculate these steps simultaneously. This method is based on a simple surface panel method “SQCM” which satisfies the Kutta condition easily. The SQCM consists of Hess and Smith type source panels on the propeller or cavity surface and discrete vortices on the camber surface according to Lan’s QCM (quasi-continuous vortex lattice method). In the first step, the cavity shape is solved by the boundary condition based on the free streamline theory. In order to get the accurate cavity shape near the tip of the propeller blade, the cross flow component is taken into consideration on the boundary condition. In the second step, we calculate the cavitating propeller and the hull surface flow simultaneously so as to calculate the pressure fluctuation including the interaction between the propeller and the hull. At that time, the cavity shape is changed at each time step using the calculated cavity shape gotten by the first step. Qualitative agreements are obtained between the calculated results and the experimental data regarding cavity shape, cavity volume and low order frequency components of the pressure fluctuation induced by the cavitating propeller.     

耦合非线性三维海洋立管的边界控制(英文)

This paper presents a design of boundary controllers implemented at the top end for global stabilization of a marine riser in a three dimensional space under environmental loadings. Based on the energy approach, nonlinear partial differential equations of motion, including bending-bending and longitudinal-bending couplings for the risers are derived. The couplings cause mutual effects between the three independent directions in the riser’s motions, and make it difficult to minimize its vibrations. The Lyapunov direct method is employed to design the boundary controller. It is shown that the proposed boundary controllers can effectively reduce the riser’s vibration. Stability analysis of the closed-loop system is performed using the Lyapunov direct method. Numerical simulations illustrate the results.     

Optimizing shipping company operations using business process modelling

In order to identify the elements constituting quality in services, a business process modelling methodology has been applied in the case of a Greek liner shipping company. The company operations have been identified and analysed in order to assess the complete performance of service elements and thereafter identify how to match the service performance against the user requirements. A liner container service within Europe has to compete with the road transport which, in many cases, is an alternative to the sea transportation and not complementary to it. Thus, not only the ship has to be envisaged when aiming to improve quality in services but also the whole chain, namely port authorities, land transportation enterprises, subcontractors, agents, charterers and others. A set of potential improvements within this framework are thus suggested and time and cost (examined in a specific voyage scenario) are measured before and after the implementation of these measures. Very large time and cost savings are observed after the application of the technology improvements, allowing, in fact, the shipping company to even increase the number of round trips per year in the examined route. This indicates that very large benefits can be drawn by analysing and critically adjusting business processes in modern shipping companies.     

Optimizing the transportation of international container cargoes in Korea

This paper considers a multimodal transportation problem, which is the problem of determining the transportation flow, i.e. volume of container cargoes, and the transportation mode in each trade route, for the objective of minimizing the sum of shipping and inland transportation costs. The problem takes account of two restrictions: maximum cargo volumes capacitated at each seaport and maximum number of vehicles available at each transportation mode. To solve optimally the problem, this paper employs a mixed integer programming, which is an operations research technique. A case study is performed on the container cargo data in Korea and we draw several implications to improve efficiency in the transportation of international trade cargoes in Korea.     

Co-operation and competition in international container transport: strategies for ports

This paper focuses on the response of port authorities to the changing market environment in which they operate. It documents the changes taking place in the relationships between port authorities and terminal management companies and considers the strategic issues faced by these groups and other port interests. In particular, it investigates the potential conflicts of interest for a port authority in matters related to the level of competition amongst terminals within a port and the amount of competition amongst ports.     

MINOE: A Software Tool to Analyze Ocean Management Efforts in the Context of Ecosystems

Transitioning ocean governance into an integrated ecosystem-based approach requires improved knowledge of existing governance arrangements. This article presents a software tool, MINOE, to assist policymakers, scientists, and others involved in ecosystem-based management initiatives to navigate through management documents as they relate to a user-defined ecosystem. The tool uses a conceptually modeled ecosystem, defined by the user, and text analysis of a set of management-related documents to determine which ecosystem linkages are potentially acknowledged in the documents. For illustration, the set of documents included with MINOE currently (and used to demonstrate the software in this article) are laws and regulations from four geopolitical jurisdictions for the year 2006; however, users may also import other documents for a more tailored application. Features include an interactive matrix containing results about the set of management documents within the user's scope and scale of interest. In addition, MINOE includes metrics and visualization tools to synthesize information derived from the documents. The article presents the software tool, describes potential uses for the tool, and ends with a discussion of future work to expand the program.     

Successful Transplantation of a Fragmenting Coral,Montipora digitata,for Reef Rehabilitation

The scleractinian coral Montipora digitata (Acroporidae) is a common reef flat species that thrives under high levels of light and water turbulence, and propagates successfully by natural fragmentation. It was used for transplantation experiments in an attempt to restore a degraded lagoon environment in the northwestern Philippines. Branches about 5 cm high from a natural population in the lagoon were transplanted to dead coral outcrops or knolls in two locations (Binlab and Malilnep-Ac) with different environmental characteristics. Growth and survival were significantly better at Malilnep Ac, which resembled the natural habitat of the species more closely. Environmental conditions at this site also favored the establishment of a greater diversity of species around the coral transplants. There was no difference in performance between transplants on vertical and horizontal surfaces, and the transplants showed limited differences due to density within the experimental range. Significant survival of detached, transplanted colonies or fragments thereof around the bases of the experimental bommies at the more successful site was an additional positive outcome. Water motion showed significant effects on survival and growth, possibly enhancing the suitability of the more successful site for transplantation. These results demonstrate the potential of coral transplantation to initiate the establishment of natural communities in degraded reef areas, a concern for coastal managers in developing countries.     

Error quantification of a high resolution coupled hydrodynamic-ecosystem coastal-ocean model: Part3, validation with Continuous Plankton Recorder data

Data collected during the Continuous Plankton Recorder (CPR) survey has been used to validate a three-dimensional hydrodynamic ecosystem model simulation of the North-west European Shelf for the years 1988–89. The CPR time series is unique to the North Atlantic region as a validation tool. Data were extracted from the model to correspond with those collected by the CPR survey, and both the model and survey plankton data were standardised to allow the comparison of model biomass with survey counts. Simple linear regression and absolute error maps provide a qualitative evaluation of spatio-temporal model performance of simulated diatoms, flagellates, total phytoplankton and omnivorous mesozooplankton. Comparisons of z-scores indicate that the model reproduces the main pelagic seasonal features, and there is good correlation between magnitudes of these features with respect to standard deviations from a long-term mean. The model is replicating up to 62% of the mesozooplankton seasonality across the domain, with variable results for the phytoplankton. There are, however, differences in the timing of patterns in plankton seasonality. The validation exercise has highlighted that the spring diatom bloom in the model is too early, suggesting the need to reparameterise the response of phytoplankton to changing light levels in the model. Errors in the north and west of the domain imply that model turbulence and vertical density structure need to be improved to more accurately capture plankton dynamics.     

Research and design of ship-shore integrated engine room intelligent operation and maintenance system based on data brain北大核心CSCD

[目的]为提升舰船机舱运维的智能化水平,针对机舱设备种类多、数量大、耦合关系复杂等特点,梳理机舱运维智能化应用的技术路线,开发船岸一体化机舱智能运维系统。[方法]首先,分析国内外机舱智能运维技术的发展趋势,融合利用健康管理、大数据挖掘、数字孪生、数据轻量化传输等技术优势;然后,设计符合舰船机舱特点的一体化智能运维系统。[结果]提出了一种基于数据大脑赋能的机舱智能运维系统功能框架、平台设计、运行体系、运行流程及关键技术应用。[结论]研究成果可为舰船机舱智能运维系统设计及应用实践提供参考。     

Marine Protected Area Management Effectiveness: Progress and Lessons in the Philippines

Quantifying progress in management of marine protected areas (MPAs) is crucial to marine conservation and fisheries management in the Philippines. This study compiles data on the status, occurrence, and management gaps of MPAs through coordination with multiple organizations supporting and guiding MPAs in the Philippines. MPA management effectiveness was measured using a MPA Rating System. Since 2002 the modal MPA rating levels increased from level 1 (initiated) to level 4 (sustained) in 2008/9. This upward trend is attributed to factors that promoted both the establishment and improved management of MPAs. Analysis indicated that: (1) most MPAs struggle with budgetary constraints or lack of sustainable financing and (2) overall the MPAs are being maintained and progressing with notable improvement in management despite a range of difficulties encountered during the implementation process. For MPAs in the Visayan Region for which biophysical data were available, the MPA Rating System was used to assess the effectiveness of local government capacity building on MPA coral reef health. Our results suggest that MPAs with higher ratings are likely to have better reef health conditions.