Buoyancy Effects on Hydrodynamics of Semi-Enclosed Bay

浮力对半封闭海湾水动力的影响

• 批准号: 02302067
• 负责人: MUROTA Akira
• 金额: $ 3.07万
• 依托单位: Osaka Sangyo University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02302067/
• 关键词: Stratified flow; Semi-enclosed Sea; Front; Water exchange; Tidal flow system; Wing-induced current; Water quality; Internal wave; 閉鎖性海域

Four research meetings have been held during two years of the project term for promoting mutual understanding about the role of density-induced currents on the hydrodynamics of semi-enclosed bays, and discussing the following synthetical themes ; (a) the effects of external forces and geometries of semi-enclosed bay on the flow and density structure ; (b) the buoyancy effects on turbulent transport of momentum and passive water qualities such as temperature, salinity and turbidity ; and (c) individual subjects studied in individual coastal and estuarine waters by co-operative investigators. The results of individual subjects are as follows :(l) Murota and Nakatsuji develop a three-dimensional baroclinic model for examining ther hydrodynamics of an estuarine front and a tidal front observed in Osaka Bay. The mutual effects of stratification, the earth's rotation and tidal modulation are clarified quantitatively.(2) Fujiwara clearly shows the estuarine circulation in Osaka, Bay on the ba … More sis of many field observations. Taking note of stratification structure in the narrow entranced embayments such as Osaka Bay, the constant current system is classified depending on the induced forces ; tidally-induces and buoyancy-induced residual currents.(3) Muraoka and Nakatsuji analyze hydrodynamically field data of temperature and velocity fluctuations which were measured related with the upwelling phenomena of 'Aoshio' (anoxic water) often observed in Tokyo Bay. A two-dimensional experiments are performed to clarify the mechanism of upwelling and mixing of two-layered stratified flow system exposed to wind stresses at the surface.(4) Murakami carries out hydraulic experiments for examining the effects of geometrically-induced horizontal circulation and buoyancyinduced vertical circulation on the water exchange when the breakwater is constructed at the mouth of enclosed bay.Furthermore, the numerical experiments were performed for clarifying the dependency of numerical schemes such as layer model and level model on the resulting difference in the computed vertical circulation.(5) Oonishi develops a system for the analysis of river effluent spreading using satellite data. Effluent from the Singuu River are analyzed as an example to study the difference in the dispersion areas detected by water temperature and water turbidity.(6) Ookubo measured temperature fluctuations due to the interfacial waves in a shallow North Lake in Australia within the range between the internal wave of buoyancy frequency and the surface wind ripple and evaluate the vertical eddy viscosity coefficient under the influence of stratification. These results are compared with observation results obtained in the south water of Biwa Lake.(7) Michioku measured temperature and velocity fluctuations in Nunobiki Reservoir, Kobe and analyzed the relationship between their fluctuations and meteorological factors such as wind and temperature. The flow structure and mixing process in a stratified reservoir are clarified. Less

在项目期限的两年期间，举行了四次研究会议，以促进相互了解密度感应流对半封闭海湾水动力的作用，并讨论了以下综合主题：(A)外力和半封闭海湾几何形状对流动和密度结构的影响；(B)浮力对动量湍流输送和被动水质，如温度、盐度和浊度的影响；(C)合作调查员在个别沿海和河口水域研究的个别课题。研究结果如下：(L)Murota和Nakatsuji发展了一个三维斜压模式，用于检验在大阪湾观测到的河口锋和潮汐锋的水动力。(2)藤原在ba…上清晰地显示了大阪、海湾的河口环流。更多的是大量的实地观察。考虑到大阪湾等狭窄入口海湾的层结结构，根据诱动力、潮汐诱生和浮力诱导的余流对恒流系统进行了分类。(3)村冈和中津分析了与东京湾经常观测到的“缺氧水”(Aoshio)上升流现象有关的温度和速度脉动的水动力学场资料。进行了二维试验，以阐明在地表风应力作用下双层层流系统的上升流和混合机理。(4)村上进行了水力试验，考察了在封闭湾口建造防波堤时，几何诱导的水平环流和浮力诱导的垂直环流对水交换的影响。此外，还进行了数值试验，以澄清层模型和水位模型等数值方案对计算垂直环流结果的影响。(5)Oonishi开发了一个利用卫星数据分析河流污水扩散的系统。以新谷河的出水为例，研究了水温和浊度对分散区域的影响。(6)Ookubo在浮力频率内波和表面风波之间测量了澳大利亚北湖浅水中界面波引起的温度波动，并估算了层结影响下的垂直涡动粘滞系数。这些结果与琵琶湖南部水域的观测结果进行了对比。(7)Michioku在神户Nunobiki水库测量了温度和速度的波动，并分析了它们与风、温度等气象因素的关系。阐明了层状油藏中的流动结构和混合过程。较少

项目成果

Nakatsuji, K.: "Outflow and Three Dimensional Spreading of River Water" Mar. Pollu. Bull.23. 31-35 (1991)

Nakatsuji, K.：“河水的流出和三维扩散”Mar. Pollu。

Fujiwara, T.: "Effect of the Earth Rotation on Tide Induced Sediment Transport" Proc. Coastal Sediment. 395-404 (1991)

Fujiwara, T.：“地球自转对潮汐引起的沉积物输送的影响”Proc。

Oonishi, S.: "Quantitative Estimation of the Diff-Area of the River Effluent with Landsat TM Data" Proc. Coastal Eng., JSCE. 38. 196-200 (1991)

Oonishi, S.：“利用 Landsat TM 数据对河流流出物的差异面积进行定量估算”Proc。

Murakami, K.: "The Influence of Horizontal and Vertcal Circulation on Water Exchange in Enclosed Bay" Proc. Coastal Eng., JSCE. 38. 836-840 (1991)

Murakami, K.：“水平和垂直循环对封闭湾水交换的影响”Proc。

Nakatsuji,K.: "Outflow and Three Dimensional Spreading of River Water in Encloced Bay" Marine Pollution Bulletin. 23. 31-35 (1991)

Nakatsuji,K.：“封闭湾河水的流出和三维扩散”海洋污染通报。