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91.
The stochastic properties of the drag force maxima on a circular cylinder subjected to nonlinear random waves are investigated. Unseparated laminar high Reynolds number flow is considered. A simplified approach based on second order Stokes waves is presented, including the sum-frequency effect only. It is demonstrated how a drag force formula valid for regular linear waves can be used to find the cumulative distribution function of individual drag force maxima for nonlinear irregular waves. Here the [Wang, 1968] drag force coefficient is used. 相似文献
92.
In-Seong Han Koichiro Kamio Takeshi Matsuno Atsuyoshi Manda Atsuhiko Isobe 《Journal of Oceanography》2001,57(2):235-249
Relation between internal waves with short time scale and density distribution near the shelf break in the East China Sea is studied utilizing moored current meters, thermometers and conductivity-temperature-depth (CTD) casts. A well developed pycnocline was frequently observed around 150–200 m depth near the shelf break accompanied with the development of internal waves with short time scale. During the cruise in May 1998, the intensified internal wave motion with short time scale and the distinct offshore flow were observed just below the lower pycnocline, which shoaled and extended above the shelf area. It is suggested that vertical mixing generated by amplified internal waves would produce cross-shelf ageostophic density current around the pycnocline. During the cruise in May 1999, on the other hand, the lower pycnocline was located offshore below the shelf break, and the internal wave motion was amplified just above the lower pycnocline. In this case, the offshore flow should be generated above the lower pycnocline, but vertical profiles of current velocity were not obtained because acoustic Doppler current profiler (ADCP) data were not available around the lower pycnocline. 相似文献
93.
C. Kranenburg 《Applied Ocean Research》1984,6(1):23-30
The rupture of a submarine oil pipeline starts various mechanisms leading to an oil spill. Among these mechanisms the leakage of oil driven by the difference in specific gravities of oil and sea-water is difficult to estimate. A simple mathematical model has been developed and laboratory experiments have been carried out to obtain an insight into the density-driven exchange flow and to determine the leak rate. The mathematical model is predictive and takes account of the effects of friction, inclination of the pipeline, and inertia of the fluid. The experiments were done in a horizontal model pipeline. Theoretical and experimental results are in satisfactory agreement. 相似文献
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96.
根据中、日合作黑潮调查研究期间(1987-1993年)在九州西侧海域获得的水文资料,计算了129°E断面的地转流速和流量。着重提出129°E断面北侧存在一支较稳定的西向流;分析这支西向流的去向,指出它是向对马暖流输送黑潮水的重要途径;给出了这支西向流及黑潮通过该断面的流速、流轴、流幅及流量的变化特征。 相似文献
97.
David K. A. Barnes 《Marine Ecology》2001,22(3):189-200
Abstract. The reef‐dwelling oyster Dendrostrea frons occupied only a small proportion of space in coral reefs of the Quirimba Archipelago, Mozambique, but supported a disproportionately high variety of taxa. Assemblages on primary (substratum), secondary (dead coral heads) and ephemeral secondary space (D. frons shells) of similar area were compared across 5 depths (5, 10, 15, 20 and 25 m) and at four taxonomic levels (species, genus, class and phylum). Differences between the taxonomic richness of each type of space differed with both taxonomic level considered and depth. Of the three categories of space considered, ephemeral secondary space had the most taxa at all levels with the maximum at 10 – 15 m. Despite being small in space and time, animal externa, such as shells of D. frons, may provide important niches for particular organisms at many taxonomic levels. 相似文献
98.
为了解南麂列岛海洋自然保护区潮间带贝类十多年来的动态变化,在1992年研究基础上,于2003年度再赴南麂列岛对岩、沙相贝类进行了研究.本次调查鉴定出贝类105种,其中岩相93种、沙相12种,6种为南麂列岛新记录种,对岩相、沙相贝类组合的生态特征进行了分析,岩相多样性和均匀度指数(1.25~2.20和0.54~0.70)高于沙相的(0.23~0.95和0.17~0.94).岩相贝类数量为3025.70g/m2和2660个/m2,生物量垂直分布为低潮区最高(6471.99g/m2),中潮区居中(3772.09g/m2),高潮区最小(78.35g/m2),栖息密度为中潮区最大(4245个/m2),低潮区居中(2973个/m2),高潮区最小(439个/m2).沙相贝类数量为16.81g/m2和11个/m2,低潮区(29.43g/m2和11个/m2)大于中潮区(14.01g/m2和10个/m2).通过与以往资料比对发现,岩礁贝类数量有所增加,沙滩贝类数量则明显下降,监控区贝类数量明显多于其他区域,对贝类资源变化产生影响的相关因子作了分析探讨. 相似文献
99.
胶州湾口海底沙波的类型、特征及发育影响因素 总被引:3,自引:1,他引:3
采用多波束资料对胶州湾口的海底沙波类型、特征进行了研究,发现研究区主要有线性沙波(二维)、沙丘(三维)2种沙波类型。结合水流流速、海底构造和表层沉积物综合分析发现:海底沙波缓坡朝向与优势流向不完全一致,为强流作用的产物,在涨、落潮作用下均可形成;沉积物的多寡是研究区海底沙波类型分布的决定因素,海底松散沉积物较为丰富的地区形成二维沙波。在水动力强大的胶州湾口,沉积物多分布在构造低洼地带,使二维线性沙波的分布与海底断裂延伸方向一致。 相似文献
100.