Strength Analysis of Turret Mooring Productive/Storage Tanker

The longitudinal strength of turret mooring productive/storage tanker is studied.A numeri-cal example has been implemented according to the method presented in this paper to give practical il-lustration.From the results of the numerical example,it is concluded that the turret hole located near theforward of the amidships has small effect on the longitudinal strength of the ship hull.As for design ex-treme value of wave bending moment of storage tanker,statistic method is a more reasonablemethodology,especially with the consideration of the servere environmental conditions.The primary esti-mation of design section modulus of turret storage tanker can be determined by this design bending mo-ment.     

Parameterization of Wave Breaking Probability and Whitecap Coverage

1 .Introduction Wave breaking and associated whitecapping have long beeninteresting due totheir close relationto many fields of ocean study,including air-sea interaction,remote sensing,ocean engineering,aswell as wave dynamics .The breaking probabilityBan…     

Three-dimensional numerical simulation of obfique wave action on vertical walls

A three-dimensional numerical model based on the potential theory was developed to study the oblique wave action on vertical walls. A source term inside the domain was used to generate incident waves and outgoing waves were dissipated by sponge layers and transmitted by radiation boundaries. The finite difference method was used to solve the governing equations and boundary conditions in the regular transformed domain in σ-coordinate. Satisfactory agreements between the numerical predictions and experimental results of wave force were obtained. It is concluded that the maximum wave force acting on the vertical walls is induced by the obliquely incident waves rather than the normally incident waves.     

用贝叶斯方法推算设计波高

采用长期概率预报提供波浪要素设计值是海洋工程中不可缺少的内容之一，文中介绍了一种基於贝叶斯原理的新计算方法，它较传统统计方法有明显的优越性，不仅可以通过补充新信息不断修正原有的估算结果，而且可以避免传统方法带来诸多不确定性，文中以北海中部百年一遇设计波高为例进行了计算。     

Automatic Registration of TOBI Side-Scan Sonar and Multi-Beam Bathymetry Images for Improved Data Fusion

Deep towed side-scan sonar vehicles such as TOBI acquire high quality imagery of the seafloor with very high spatial resolution but poor locational accuracy. Fusion of the side-scan sonar data with bathymetry data from an independent source is often desirable to reduce ambiguity in geological interpretations, to aid in slant-range correction and to enhance seafloor representation. The main obstacle to fusion is accurate registration of the two datasets.The application of hierarchical chamfer matching to the registration of TOBI side-scan sonar images and multi-beam swath bathymetry is described. This matches low level features such as edges in the TOBI image, with corresponding features in a synthetic TOBI image created by simulating the flight of the TOBI vehicle through the bathymetry. The method is completely automatic, relatively fast and robust, and much easier than manual registration. It allows accurate positioning of the TOBI vehicle, enhancing its usefulness as a research tool. The method is illustrated by automatic registration of TOBI and multi-beam bathymetry data from the Mid-Atlantic Ridge.     

长江口区风浪要素计算的探讨

本文以长江口区波浪实测资料为依据，对目前国内外常用的风浪要素计算方法进行了比较分析，认为就目前资料条件下，最适用于长江口区的、能满足工程设计等要求的风浪要素计算方法为莆田试验站方法（莆田公式）。     

A Preliminary Study of Shear Wave in Seafloor Surface Sediments

This article preliminarily reports and analyses the transmission characteristics and behaviors of shear wave in the offshore seafloor surface sediments in China, discusses the relationships between the physical and mechanical features of the shear wave and the compression wave, and compares the testing results with that of Hamilton and Chen et al. The result shows that the shear wave can be tested if the seafloor surface sediment has tangent modulus. The shear wave velocity ranges from 50-600 m/s and the measuring frequency from 50-200 kHz. The sound velocity rate of shear wave and compression wave can be used to appraise the stress-strain feature of seafloor surface sediments. This study provides a basis for further describing and appraising the seafloor sedimentary acoustic-mechanical feature and building a geological-acoustic model on China's offshore sea area.     

Wave Defending Effects of V-Type Bottom-Mounted Breakwaters

An analytical method is developed for the study of the wave defending effects of the V-type bottom-mounted breakwater. The breakwater is assumed to be rigid, thin, impermeable and vertically located in water of constant depth. The fluid domain is divided into three sub-regions by an imaginary interface. The velocity potential in each region is expanded by eigenfunctions. By satisfying the corresponding boundary conditions and matching conditions in and between sub-regions, a set of hnear algebraic equations can be obtained to determine the unknown coetfficients for the eigenfunction expansions for each sub-region. The accuracy of the present model is verified by a comparison with existing results for the case of an isolated breakwater. Numerical results, in the form of contour maps of the relative wave amplitude around the breakwater, are presented for a range of wave and breakwater parameters. The results show that the V-type bottommounted breakwater is generally effective in defending against waves. In general, the wave height in the protected area is about 20-50 percent of the incident wave height.     

风暴期间黄河水下三角洲波浪变形

为确定适用黄河三角洲的波动理论，对黄河三角洲风暴期间及前后波浪连续观测资料进行了处理，将其投在komar波浪理论分区图中后，分析了风暴期间黄河水下三角洲波浪的波形特征，发现站位所在地适合的波浪理论主要为艾里波和斯托克斯波，风暴期间波浪变形，还存在少量超过极限波陡线的波浪，通过比较常见的极限波陡线，看出Miche曲线比较适合该研究区。