Antifoulant concentrations at the site of the Bunga Teratai Satu grounding,Great Barrier Reef,Australia   总被引：1，自引：0，他引：1  

Haynes D  Christie C  Marshall P  Dobbs K 《Marine pollution bulletin》2002,44(9):968-972

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Stability of small fishing vessels in longitudinal waves     

M. A. S. Neves  N. A. Prez  L. Valerio 《Ocean Engineering》1999,26(12):347

The dynamic stability of fishing vessels in longitudinal regular waves is investigated, both analytically and experimentally. In particular, the influence of stern shape on the parametric stability of fishing vessels is studied. Vessels TS and RS have very similar main characteristics, but their sterns are different. Although their linear responses are comparable, both analytical and experimental investigations indicate substantial differences in their dynamic stability in longitudinal regular waves. Strong resonances are found for the vessel with the deep transom. The analytical method takes into consideration the effects of the heave and pitch motions and wave passage and shows good agreement with experimental results. Stability limits are obtained for different conditions and are used as an aid in the discussion of the results obtained in the tests when relevant parameters are changed, such as wave amplitude and frequency, metacentric height and roll damping moment.  相似文献   

Performance of Landsat TM in ship detection in turbid waters     

Guofeng Wu  Jan de Leeuw  Andrew K. Skidmore  Yaolin Liu  Herbert H.T. Prins 《International Journal of Applied Earth Observation and Geoinformation》2009

The visible and near infrared bands of Landsat have limitations for detecting ships in turbid water. The potential of TM middle infrared bands for ship detection has so far not been investigated. This study analyzed the performance of the six Landsat TM visible and infrared bands for detecting dredging ships in the turbid waters of the Poyang Lake, China. A colour composite of principal components analysis (PCA) components 3, 2 and 1 of a TM image was used to randomly select 81 dredging ships. The reflectance contrast between ships and adjacent water was calculated for each ship. A z-score and related p-value were used to assess the ship detection performance of the six Landsat TM bands. The reflectance contrast was related to water turbidity to analyze how water turbidity affected the capability of ship identification. The results revealed that the TM middle infrared bands 5 and 7 better discriminated vessels from surrounding waters than the visible and near infrared bands 1–4. A significant relation between reflectance contrast and water turbidity in bands 1–4 could explain the limitations of bands 1–4; while water turbidity has no a significant relation to the reflectance contrast of bands 5 and 7. This explains why bands 5 and 7 detect ships better than bands 1–4.  相似文献   

Application of the extended Melnikov's method for single-degree-of-freedom vessel roll motion   总被引：2，自引：0，他引：2  

Wan Wu  Leigh McCue   《Ocean Engineering》2008,35(17-18):1739-1746

Traditionally, when using Melnikov's method to analyze ship motions, the damping terms are treated as small. This is typically true for roll motion but not always true for other and/or multiple degrees of freedom. In order to apply Melnikov's method to other and/or multiple-degree-of-freedom motions, the small damping assumption must be addressed. In this paper, the extended Melnikov method is used to analyze ship motion without the constraint of small linear damping. Two roll motion models are analyzed here. One is a simple roll model with nonlinear damping and cubic restoring moment. The other is the model with biased restoring moment. Numerical simulations are investigated for both models. The effectiveness and accuracy of this method is demonstrated.  相似文献   

A parametric study of wave loads on trimaran ships traveling in waves   总被引：3，自引：0，他引：3  

Ming-Chung Fang  Tse-Yin Chen 《Ocean Engineering》2008,35(8-9):749-762

In this paper, we present a spectral analysis based on wave loads to select suitable side-hull arrangements for a trimaran ship traveling in waves. Neglecting the steady flow effect, the three-dimensional source-distribution method, using a pulsating source potential incorporating the panel method, is adopted to solve the corresponding hydrodynamic coefficients. The significant values for wave loads, including shear forces, bending moments, and torsion moments at different locations on the main hull and connected deck with respect to different staggers and clearances, are derived by the spectral analysis. Several ship speeds and wave headings are also considered for comparison. This study offers more information for selecting the side-hull arrangement from the viewpoint of wave loads on trimaran ships, which may be regarded as helpful references for seakeeping design of these types of ships.  相似文献   

海洋地质十号船钻探系统及其在海洋地质调查中的应用          下载免费PDF全文

王世栋  田烈余  王俊珠  陈以沫 《探矿工程》2020,47(2):24-29

能源需求持续增长及环境污染防治、应对气候变化要求加快能源结构调整,迫切需要海洋地质调查工作为油气勘探开发提供新的靶区,为天然气水合物商业化勘查开发提供基础支撑。我国自主设计、建造的海洋地质十号船填补了我国小吨位大钻深海洋地质钻探船的空白,提升了海洋地质调查能力,也标志着我国海洋地质综合调查能力跻身世界前列,并为未来的大洋钻探提供了宝贵的经验。海洋地质十号船钻探系统针对不同地层采用不同的取心工具,顺利完成了南海某海域的钻探取心任务(A、B两个钻孔)。针对海洋钻探作业风险,制定的应对措施,保证了海洋地质十号船钻探作业的正常施工。实践证明,海洋地质十号船钻探系统可圆满完成了海洋地质钻探取心任务。  相似文献   

基于海洋渔业发展的海洋科考船建造和应用          下载免费PDF全文

刘永新  刘晃  徐琰斐 《海洋开发与管理》2019,36(2):76-79

为提高我国海洋科考船的建造和应用水平,促进远洋和极地渔业发展,文章根据国内外海洋科考船的发展历史和现状,分析我国海洋科考船在海洋渔业发展中存在的问题以及海洋科考船的发展趋势,并提出相关建议。研究结果表明:国际海洋科考船发展早、数量多且装备先进;我国海洋科考船发展较快,但仍需提升数量和技术,在建和研发船舶具有世界领先水平;在促进海洋渔业发展方面,我国海洋科考船存在远洋和极地调查能力以及集成功能较弱的问题;基于海洋科考船在提高极地作业能力等方面的发展趋势以及海洋渔业发展需求,我国海洋科考船的建造和应用应加强顶层设计、技术应用和数据共享。  相似文献   

Full scale CFD seakeeping simulations for case study ship redesigned from V-shaped bulbous bow to X-bow hull form     

《Applied Ocean Research》2019

Increasing propulsion efficiency, safety, comfort and operability are of the great importance, especially for small ships operating on windy sites like the North Sea and the Baltic Sea. Seakeeping performance of ships and offshore structures can be analysed by different methods and the one that is becoming increasingly important is CFD RANS. The recent development of simulation techniques together with rising HPC accessibility enables performance of advanced seakeeping simulations for ships in a full scale. The paper presents CFD seakeeping analysis for a case study vessel in two variants: V-shaped bulbous bow hull form (as built) and innovative hull form (X-bow type). The study presents the influence of redesigning the ship on selected seakeeping aspects. The advanced CFD model, with the application of overset mesh technique, was described in detail. Selected numerical results were validated on the basis of experimental testing in a towing tank and showed good agreement. The approach demonstrated here of performing the CFD seakeeping simulations for the analysis of ship performance in a full scale and close to real loading conditions has direct application to the design process as well as in determination of optimal operational parameters of any ship.  相似文献   

Experimental studies of a damaged ship section in forced heave motion     

《Applied Ocean Research》2019

This work documents a detailed series of experiments performed in a wave flume on a thin walled prismatic hull form. The model consists of a rectangular opening located on the side. The length of the model is slightly smaller than the flume breadth to achieve two-dimensional (2D) behavior in the experiments. Forced oscillatory heave tests in calm water have been carried out by varying the model-motion parameters and examining both intact and damaged conditions. Video recordings, measurements of the wave elevation inside the damaged compartment and of the force on the model were performed in all the experiments. The effect of damage opening in the model on hydrodynamic loads is examined by comparing with an intact section. A theoretical analysis is used to explain the behavior of added mass and damping coefficients in heave for a 2D damaged section. The presented results demonstrate occurrence of sloshing and piston mode resonances in the tests and their influence on the hydrodynamics loads of a damaged ship. Detailed physical investigations are presented at these resonance frequencies for the damaged section. Effect of filling level in the damage compartment, damage-opening length and air compressibility in the airtight compartment is examined. Nonlinear effects are documented and appear dominant, especially, for lowest filling level where we have shallow-water depth conditions in the damaged compartment. Resonance phenomena that can lead to significant local loads are identified for the shallow water condition. Air compressibility in the airtight compartment and floodwater act as a coupled system and influence inflow/outflow of floodwater in the compartment. It has a significant effect on local floodwater behavior in the damaged compartment.  相似文献   

Optimal ice routing of a ship with icebreaker assistance     

《Applied Ocean Research》2019

Offshore development and growing prospects of commercial shipping in the Arctic pose the challenge of optimal ship routing in ice. Route selection in spatially distributed ice conditions significantly affects the voyage time and determines the efficiency of shipping. Most of the applied methods of ice routing solve the problem of a single vessel route selection without considering icebreaker support. At the same time, the real practice of ice navigation is closely connected with icebreaker assistance. It allows reducing the voyage time and fuel consumption, while having additional costs for icebreaker services. Such opposite trends set an optimization task that has not been studied in detail before. In this article, we presented the formulation of a Single Vessel and Icebreaker Assisted Ice Routing optimization problem in non-stationary ice conditions. We considered the icebreaker assistance as an integral part of the overall route optimization problem, and used the economic criterion to optimize both ship route and amount of icebreaker involvement. The article contains the adapted mathematical formulations of classical graph-based and wave-based routing problems in order to consider icebreaker assistance. To prove the practical applicability of these formulations, we developed special subject-oriented research software and implemented there both graph-based (Dijkstra, A*) and the wave-based ice routing methods. Using this developments, we conducted several case studies and made the analysis of strengthens and weaknesses of the alternative routing methods in case of ice operation. The results of the study may serve an additional step to the practical implementation of ice routing technologies and planning of icebreaker resources.  相似文献