River Plume Dynamics in Estuary

向静止沃茨（如河流羽流和热羽流）的浮力表面排放的特征在于流场和密度场的三维结构，其大部分受水平压力梯度和排放和接收沃茨之间的密度差以及动量通量所导致的分层的控制。此外，它们的行为可能会发生变化，这取决于周围近海的流场和密度场以及河口附近的地理特征。本文建立了一个考虑自由水面的河流羽流扩散的三维原始数值模式。湍流切应力和湍流浮力通量用涡粘性系数和扩散系数表示，其中考虑了层结效应，通过数值计算结果与已发表的实验数据的比较，用经验公式表示，并与河流实验结果进行了比较 关于我们 具有小密度弗劳德数的羽流，在明石川进行的实地观测结果，以及淀川洪水的红外图像。结果阐明了河口附近羽流扩散的特殊机制，即水流加速、河水扩散和抬升现象。数值模式已被应用到河流羽流排放到横流和复杂的地理特征。特别地，从科学的角度，用k-S湍流模型分析了河口地形的扩展角对河口羽流三维结构的影响，在较大尺度上，Rossby形变半径、地球自转以及浮力是引起强地转沿岸流的主要动力。因此，淀川羽流沿着科比和淡路岛的海岸线向右流动，同时在洪水的情况下形成狭窄的海岸急流。计算的密度场与8210号台风洪水期间NOAA卫星拍摄的红外图像吻合较好。然而，如果有潮汐流，其产生的电流超过密度驱动的电流，增强潮汐漂移的河流羽流，除非海岸急流的传播速度太高。相反，密度效应有助于潮汐余流系统的形成。少

Buoyant surface discharges into stagnant waters such as river plume and thermal plume are characterized by the three-dimensional structure of flow and density fields, which is for the most part controlled by horizontal pressure gradients and the stratification resulting from the density difference between discharged and receiving waters as well as momentum fluxes. Furthermore, their behaviors may change depending on the flow and density fields of ambient coastal seas and the geographical features near the river mouth. A three-dimensional, primitive numerical model with a free water surface is developed for examining the river plume spreading. Turbulent shear stresses and turbulent buoyant fluxes are expressed in terms of the eddy viscosities and diffusivities, in which the stratification effects are taken into account with empirical formulae through the comparison of numerical results with published experimental data.The model predictions are compared with experimental results of river … More plumes with small densimetric Froude numbers, field observation results performed in the Akashi River, and the infrared image of the YodoRiver in flood. As a result, the mechanism peculiar to river plume spreading near the river mouth is clarified; that is, the flow acceleration, the divergence of river water and the lift off phenomena. The numerical model has been applied to river plumes discharged into cross flows and into complicated geographical features. In particular, the effects of spreading angle of river mouth topology on the three-dimensional structure of river plumes are evaluated by using a k-epsilon turbulence model from the scientific point of view.On a larger scale, the Rossby deformation radius, the earth's rotation in addition to the buoyancy are the major forces that cause a strong geostrophic along-shore current. Consequently, the Yodo River plume flows to the right along the coastal line of Kobe and Awaji Island while forming a narrow coastal jet in the case of flood. The computed density field shows good agreement with the infrared image taken by the NOAA satellite during the flood flow of typhoon 8210. If there is a tidal flows, however, its producing current exceeds the density-driven current, enhancing the tidal excursion of the river plume unless the propagation speed of the coastal jet is too high. Instead, the density effect assists in the formation of the tidal residual current system. Less