Buoyancy Effects on Hydrodynamics of Semi-Enclosed Bay

在两年的项目期内，已经举行了四次研究会议，以促进对密度诱导流在半封闭海湾水动力学中作用的相互理解，并讨论了以下综合主题：（a）外力和半封闭海湾几何形状对水流和密度结构的影响;（B）浮力对动量湍流输送的影响，以及被动水的水质，例如温度、盐度和浊度;及（c）由合作研究人员在个别沿岸和河口沃茨进行的个别研究。（1）Murota和Nakatsuji发展了一个三维斜压模式，用于研究大坂湾河口锋和潮汐锋的水动力。定量地阐明了层结、地球自转和潮汐调制的相互作用。(2)藤原清楚地显示了大坂湾的河口环流， ...更多信息 许多实地观察结果。考虑到大坂湾等狭窄海湾的分层结构，根据诱导力、潮汐诱导和浮力诱导的余流对恒流系统进行分类。(3)Muraoka和Nakatsuji分析了温度和速度波动的水动力场数据，这些数据与东京湾经常观察到的“Aoshio”（缺氧水）的上升流现象有关。通过二维实验研究了风应力作用下双层分层流系统的上升流和混合机制。(4)Murakami通过水力学试验研究了在封闭海湾口部建造防波堤时，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，并通过数值试验研究了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)大西开发了一个利用卫星数据分析河流污水扩散的系统。以新古河的出水为例，研究了水温和浊度对扩散区的影响。(6)Ookubo在澳大利亚的一个浅北湖中测量了浮力内波频率和表面风涟漪之间的范围内由于界面波引起的温度波动，并评估了分层影响下的垂直涡动粘性系数。这些结果与在琵琶湖南部水域获得的观测结果进行了比较。(7)在科比的Nunobiki水库中测量了温度和速度的波动，并分析了它们的波动与风和温度等气象因素之间的关系。阐明了分层水库中的水流结构和混合过程。少

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