Rain-Flow and Reverse Rain-Flow Counting Method for the Compilation of Fatigue Load Spectrum     

宋玉普  王立成  李朝阳 《中国海洋工程》2001,(3):429-435

The rain-flow counting method is widely used to compile the fatigue load spectrum. The second stage counting of the rain-flow method is a troublesome process. In order to overcome this drawback, the rain-flow and reverse rain-flow counting method is proposed in this paper. In this counting method, the rule for counting of the rain-flow method is modified, so that the sequence of load-time need not be adjusted. This is a valid and useful method to count cycles and compile the load spectrum and it can be widely used in ocean engineering.  相似文献   

Parameter identification of a compliant nonlinear SDOF system in random ocean waves by reverse MISO method     

R. Panneer Selvam  S. K. Bhattacharyya   《Ocean Engineering》2001,28(9):33

The determination of the drag and inertia coefficients, which enter into the wave force model given by Morison's equation, is particularly uncertain and difficult when a linear spectral model is used for ocean waves, and the structure is compliant and has nonlinear dynamic response. In this paper, a nonlinear System Identification method, called Reverse Multiple Inputs–Single Output (R–MISO) is applied to identify the hydrodynamic coefficients as well as the nonlinear stiffness parameter for a compliant single-degree-of-freedom system. Four different types of problems have been identified for use in various situations and the R–MISO has been applied to all of them. One of the problems requires iterative solution strategy to identify the parameters. The method has been found to be efficient in predicting the parameters with reasonable accuracy and has the potential for use in the laboratory experiments on compliant nonlinear offshore systems.  相似文献   

渤、黄、东海夏季环流的三维斜压模型   总被引：10，自引：0，他引：10  

王凯  冯士筰  施心慧 《海洋与湖沼》2001,32(5):551-560

基于拉格朗日时均观点描述环流，建立起潮流与准定常流共同占优势系统中的陆浅海环流模型，并诊断计算了夏季渤、黄、东海的三维环流图。模拟结果较好地再现了渤、黄、东海主要流系的特征。对照冬季结果，对渤、黄、东海环流的季节变化做了阐述。从环流垂向分量的分布图上，可发现渐闽近海、长江口外存在较明显的上升流区。另外，对夏季渤、黄、东海的热盐环流和潮致余流分别进行了模拟，发现它们均能在黄海构成一逆时针向的五流系统，这对形成和维持夏季黄海冷水团的存在有重要作用。热盐环流的模拟结果表明，黄海冷水团环流含有“热成流”的成分；通过Lagrange余流的计算发现环绕黄河冷水团的环流还含有“潮成流”的成分。  相似文献   

A method of determining dominant wave direction from multiparameter hydrological gauge measurements and its application     

WANG Sheng''an  LONG Xiaomin  ZHANG Keben  CHEN Junchang  ZHANG Wenjing  CAI Shuqun 《海洋学报(英文版)》2007,26(3):160-166

Multi-parameter hydrological gauge is an instrument developed by the South China Sea Institute of Oceanology,the Chinese Academy of Sciences to make simultaneous observation of current, wave, tide, water temperature and conductivity.By using the well-known "PUV method", the directional wave spectrum can be calculated and the dominant wave direction is then obtained.The comparison of the dominant wave directions derived from the measurements using both the multi-parameter hydrological gauge and the MARK Ⅱ "Wave-Rider" directional buoy shows that the dominant wave directions derived from the two kinds of measurements are in good agreement.  相似文献   

Fluctuations of peak energy and peak frequency of local wavelet energy spectrum for wind waves     

Wu Kejianl  Lou Shunli 《海洋学报(英文版)》1997,16(4):429-439

Ｆｌｕｃｔｕａｔｉｏｎｓ　ｏｆ　ｐｅａｋ　ｅｎｅｒｇｙ　ａｎｄ　ｐｅａｋ　ｆｒｅｑｕｅｎｃｙ　ｏ　ｌｏｃａｌ　ｗａｖｅｌｅｔ　ｅｎｅｒｇｙ　ｓｐｅｃｔｒｕｍ　ｆｏｒ　ｗｉｎｄ　ｗａｖｅｓTXＦｌｕｃｔｕａｔｉｏｎｓｏｆｐｅａｋｅｎｅｒｇｙａｎｄｐｅａｋ...  相似文献   

双峰谱型海浪的波高和周期分布     

陈雪英 《海洋科学进展》1996,(2)

本文利用收集到的实测双峰谱型海浪过程资料，把这些资料以波高和周期的相关系数为参数分成５组，讨论每组双峰谱型下被高、周期的统计分布．并探讨了相关系数对波高分布和周期分布的影响。  相似文献   

A proposed directional function and wind-wave directional spectrum   总被引：4，自引：0，他引：4  

Wen Shengchang  Wu Kejian  Guan Changlong  Sun Shicai  Zhang Dacuo 《海洋学报(英文版)》1995,14(2):155-166

Ａｐｒｏｐｏｓｅｄｄｉｒｅｃｔｉｏｎａｌｆｕｎｃｔｉｏｎａｎｄｗｉｎｄ－ｗａｖｅｄｉｒｅｃｔｉｏｎａｌｓｐｅｃｔｒｕｍ￥ＷｅｎＳｈｅｎｇｃｈａｎｇ；ＷｕＫｅｊｉａｎ；ＧｕａｎＣｈａｎｇｌｏｎｇ；ＳｕｎＳｈｉｃａｉａｎｄＺｈａｎｇＤａｃｕｏ（Ｒｅｃｅｉ...  相似文献   

断阶型潜山带地质模型的建立及储层预测--以CG20潜山为例     

姜素华  王永诗  张家震  王军 《中国海洋大学学报(自然科学版)》2004,34(3):437-445

以 CG2 0潜山为例 ,从建立地质模型入手 ,包括地层模型、构造模型、储集模型、储盖组合模型、速度模型等 ,认识到各套地层分布和储层物性的差异均与地震响应密切相关 ,因此可以利用地震波的信息 ,预测潜山储层的发育及分布情况。在对 CG2 0潜山进行精细全三维构造解释的基础上 ,探讨性地应用了测井约束反演、吸收系数、相干分析及三维模式识别等技术 ,对潜山储层进行了预测 ,从而提高了潜山勘探的效益 ,并为类似断阶型潜山带的勘探提供了成功的经验 ,具有一定的指导意义。  相似文献   

Outer wave number spectrum and statistical distribution of apparent wave number vector     

J. -B. Song  K. -J. Wu  Y. -H. Wu 《Ocean Engineering》2003,30(3):401-412

Based on the ray theory and Longuet-Higgins’s linear model of sea waves, the joint distribution of wave envelope and apparent wave number vector is established. From the joint distribution, we define a new concept, namely the outer wave number spectrum, to describe the outer characteristics of ocean waves. The analytical form of the outer wave number spectrum, the probability distributions of the apparent wave number vector and its components are then derived. The outer wave number spectrum is compared with the inner wave number spectrum for the average status of wind-wave development corresponding to a peakness factor P = 3. Discussions on the similarity and difference between the outer wave number spectrum and inner one are also presented in the paper.  相似文献   

Optimum Sample Size to Detect Perturbation Effects: The Importance of Statistical Power Analysis – A Critique     

Marco Ortiz 《Marine Ecology》2002,23(1):1-9

Abstract. The current article describes statistical power analysis as an efficient strategy for the estimation of the optimum sample size. The principle aim is constructively to criticise and enrich the results presented by Mouillot et al. (1999) , who estimate the optimum sample size for evaluating possible perturbations. The authors did not make any reference to statistical power analysis, even though their objective clearly went beyond a simple stock evaluation to assess management strategies in a particular marine ecosystem. Surprisingly, they proposed (a priori) an ANOVA design to test a hypothesis considering both space and temporal scales. However, the authors did not cover important topics related with power analysis and the precautionary principle, both used into environment impact assessment programmes for marine ecosystems. Based on their results and on statistical power analysis, it is demonstrated that the variability (dispersion statistics), a key factor they used to estimate the sample size, is less relevant than the magnitude of perturbation (effect size). Therefore, a greater effort must be devoted to estimate the effect size of a particular phenomenon rather than a desired variability.  相似文献