Numerical flow analysis of single-stage ducted marine propulsor   总被引：1，自引：0，他引：1  

Warn-Gyu Park  Young-Rae Jung  Chan-Ki Kim 《Ocean Engineering》2005,32(10):1260-1277

The present work has solved 3D incompressible RANS equations on a rotating, non-orthogonal multi-blocked grid to efficiently analyze a ducted marine propulsor with rotor–stator interaction. To handle the interface boundary between a rotor and a stator, the sliding multi-block technique using the cubic spline interpolation and the bilinear interpolation was applied. To validate the present code, the flow of a single stage turbine flow was simulated. Time averaged pressure coefficients were compared with experiments and good agreements were obtained. After the code validation, the flowfield around a single-stage ducted marine propulsor having a single stage of rotor and stator was successfully simulated and the hydrodynamic performance coefficients were computed.  相似文献   

The Increase of Biogenic Sulfate Aerosol and Particle Number in Marine Atmosphere over the Northwestern North Pacific     

Atsushi Ooki  Kazuhiko Miura  Mitsuo Uematsu 《Journal of Oceanography》2003,59(6):799-807

During a cruise aboard the R/V Hakuho-maru in the northwestern North Pacific in the summer of 1998 the particle number concentrations and the major ionic components of size fractionated aerosols were measured to investigate the aerosol produced by marine biological activity. Continuous low concentrations of nitrate (<1.8 nmol m⁻³), similar to the marine air background level, were found over the northwestern North Pacific (40–45°N) and the Sea of Okhotsk (44–45°N). Over the Sea of Okhotsk, a high concentration of chlorophyll-a (5.4 mg m⁻³) in seawater was observed, and atmospheric concentrations of non sea-salt (nss-) sulfate (44 nmol m⁻³), methane sulfonic acid (MSA) (1.8 nmol m⁻³) and particle number in the size range of 0.1 < D < 0.5 μm (199 cm⁻³) were found to be 9, 7, and 2 times, respectively, higher than those in the background marine air. The increase in particle number concentrations mainly in the size range of 0.2 < D < 0.3 μm was likely caused by the increase of biogenic sulfate over the high productive region of the Sea of Okhotsk. In humid air conditions (R.H. > 96%), the increased biogenic sulfate that condensed the large amount of water vapor would not have sufficient solute mass to activate as cloud condensation nuclei (CNN) and would remain as aerosol particles in the marine air with frequent sea-fogs over the high productive region. Biogenic sulfate originating from dimethyl sulfide (DMS) would gradually grow into the CCN size and continuously supply a great number of CCN to the marine air in the northwestern North Pacific. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Characterisation of Heterotrophic Microorganisms Isolated form the "Grotta Azzura" of Cape Palinuro (Salerno, Italy)     

Francesco Canganella  Giovanna Bianconi  Agata Gambacorta  Chiaki Kato  Katsuyuki Uematsu 《Marine Ecology》2002,23(S1):1-10

Abstract. Hydrothermal vent ecosystems have been extensively investigated during the last 20 years; shallow water hot springs (typically found below 50 m depth) have also been studied, and from these ecosystems many thermophilic and hyperthermophilic organisms were isolated and described.
The submarine caves of Cape Palinuro were discovered long ago, but only during the last decades were geological and biological investigations carried out, yielding a large number of reports on this fascinating environment. During the last two years, several samples of water, mud, and/or bacterial mat were collected within the "Grotta Azzurra", and enrichment experiments were performed using peptone, starch, glucose or pullulan as main organic nutrients. Many heterotrophic strains were isolated and most of them grew optimally between 37 and 43 ° C with the addition of 0-2 % NaCl. Growth was usually observed between 10 and 50 ° C the range of growth pH was 4 to 9, and NaCl concentrations up to 10–12 % were tolerated in most cases.
The analysis of 16S rDNA performed with the most representative isolates showed a close phylogenetic relationship with the genera Bacillus, Vibrio, Citrobacter and Escherichia. Moreover, an isolate showing morphological and physiological similarities with the genus Enterococcus was characterised and taxonomically described based on the 16S rDNA sequence.  相似文献   

Effects of fisheries on marine ecosystems: a conservationist's perspective   总被引：4，自引：1，他引：4  

Agardy  Tundi 《ICES Journal of Marine Science》2000,57(3):761-765

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Gravity analysis offshore the Canary Islands from a systematic survey     

A. Carbó  A. Muñoz-Martín  P. Llanes  J. Álvarez 《Marine Geophysical Researches》2003,24(1-2):113-127

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海洋沉积物中氮的形态及其生态学意义     

吕晓霞  宋金明 《海洋科学集刊》2003,(45):101-111

海洋沉积物作为生源要素氮的重要源与汇，在其生物地球化学循环中起着至关重要的作用。该项研究旨在查清海洋沉积物中氮的存在形态及其生态学意义。氮是生物生命活动必需的营养要素，海洋中的氮往往是海洋初级生产力的限制因子，氮的吸收与再生释放在估算海洋新生产力和生源要素的生物地球化学循环率上也有重要贡献。海洋沉积物中的氮作为海水中氮的重要供给源是海洋生物赖以生存的重要物质基础，对维持海洋生态平衡、修复失衡的海洋生态环境具有重要意义。但由于不同海区海洋沉积物的来源和环境不同，氮的形态和含量亦不相同，可被生物吸收和利用的数量就不相同，因此造成了不同海区生物种群和环境不同，进而影响生态环境。因此，研究海洋沉积物中氮的形态，了解各个形态与沉积物中生物种群及与环境的关系，确定其生物和化学活性，査清氮不同形态的生态学功能，对于深入探讨海洋生物资源可持续利用的方法和策略具有重要意义。本文主要阐述海洋沉积物中氮的存在形式与分布、氮的早期成岩和去营养化作用、硝化和反硝化作用以及氮与生物特定种群的关系等，探讨了影响海洋沉积物中的氮循环的主要因素，并分析了海洋沉积物中的氮与生态系的关系，以期对研究氮的海洋生物地球化学过程有所帮助。  相似文献   

渤海动力对黄河入海泥沙输移的影响   总被引：3，自引：0，他引：3  

吴永胜  王兆印 《海洋科学进展》2002,20(2):22-30

海洋动力过程对黄河入海泥沙的淤积和扩散具有决定性作用 ,利用三维斜压动力 -泥沙模型分析了黄河口外海域潮流动力变化与黄河入海泥沙淤积、扩散特性之间的响应关系。季节环流以及涨落潮的分布和变化很好地解释了黄河口南北浮泥的形成和消长变化以及黄河入海泥沙向海扩散的机理。结果表明 ,入海泥沙在洪季、枯季和表底层都具有不同的输移特性  相似文献   

胜利原油和Corexit 9527分散剂对海洋围隔实验生态系中浮游动物的影响     

陈孝麟  C.M.拉里 《台湾海峡》1992,(4)

本文分析了Corexit 9527分散剂和中国胜利原油对海洋实验生态系中浮游动物群落的影响,得出的主要结论是:1.单独的Corexit 9527对草食性桡足类的生长发育稍有抑制作用,但种群可得恢复和发展,对肉食性桡足类及其他各类浮游动物没有影响;2.Corexit 9527和原油的混合物对所有类别浮游动物均有极大的抑制作用,它导致种群的迅速缩小且无法得以恢复。  相似文献   

"百合"台风近海加强成因分析   总被引：3，自引：0，他引：3  

林毅  刘爱鸣  刘铭 《台湾海峡》2005,24(1):22-26

利用卫星云图、常规观测资料对“百合”台风减弱为低压后在台湾海峡南部海面强度再次加强，又发展成强热带风暴的过程分析诊断结果表明：“百合”台风近海加强的主要原因是台风上层强辐散流场的叠加，加强了台风环流的垂直上升运动；台湾海峡南部的暖洋区的增暖增湿、中低层辐合流场的加强和低层适度冷空气的侵入对台风的加强也起了一定的作用．  相似文献   

Estimation of Marine Soil Parameters for Preliminary Analysis of Geotechnical Structures in the Taiwan Strait Connection Project     

Jian-Hua Yin  Hong-Jian Liao  Cheng Zhou  Chun-Man Cheng 《Marine Georesources & Geotechnology》2003,21(3):167-182

No direct site investigation (SI) data are available for the prospective Taiwan Strait connection project. Any quantitative analysis on the performance of a tunnel, a bridge, or of on-shore (or off-shore) connections needs reasonable geotechnical model parameters. Correlations between basic properties of marine soils and geotechnical model parameters have been established before by the first author based on a large amount of laboratory test data. The established correlations together with other relations considering main types of soils in the Taiwan Strait region are used to estimate the geotechnical model parameters of the marine soils. These correlations and estimated values of the geotechnical parameters of the marine soils are presented and discussed in this article. The estimated geotechnical model parameters can be used for a preliminary analysis of the performance of geotechnical structures of the prospective project.  相似文献