Buoyancy Effects on Hydrodynamics of Semi-Enclosed Bay

浮力对半封闭海湾水动力的影响

基本信息

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

项目摘要

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

在项目期限的两年内举行了四次研究会议，以促进对密度诱发流对半封闭海湾水动力作用的相互了解，并讨论以下综合主题：(a) 外力和影响；半封闭海湾的几何形状对流量和密度结构的影响；(b) 浮力对动量的湍流传输和被动水质（例如温度、盐度和浊度）的影响；以及 (c) 在个体中研究的个体课题；合作研究人员对沿海和河口水域的研究结果如下：(l) Murota 和 Nakatsuji 开发了一个三维斜压模型，用于检查在大阪湾观察到的河口锋和潮汐锋的流体动力学。定量地阐明了层结、地球自转和潮汐调节的相互影响。(2)藤原清楚地显示了大阪、海湾的河口环流…考虑到大阪湾等狭窄入口海湾的层结结构，恒流系统根据潮汐引起的剩余电流和浮力引起的剩余电流进行分类。（3）Muraoka和Nakatsuji。分析与东京湾经常观察到的“Aoshio”（缺氧水）上升流现象相关的温度和速度波动的流体动力学现场数据。进行了二维实验。阐明两层分层流系统在地表风应力作用下的上涌和混合机制。(4)Murakami进行了水力实验，以研究几何引起的水平环流和浮力引起的垂直环流对水交换的影响。防波堤建在封闭湾口。此外，还进行了数值实验，以澄清层模型和水平模型等数值方案对计算的垂直环流差异的依赖性。（5）大西开发以利用卫星数据分析河流污水扩散的系统为例，研究了水温和水浊度检测到的扩散区域的差异。(6) Ookubo 测量了界面引起的温度波动。分析了澳大利亚北湖浅水浮力频率内波与表面风纹之间的波浪，并评估了层结影响下的垂直涡粘系数。 (7)Michioku测量了神户布引水库的温度和速度波动，并分析了它们的波动与风、温度等气象因素的关系，分析了分层中的流动结构和混合过程。水库澄清较少。