Time-Space Variations of Hydraulic Parameters and Mixing Processes at the Density interface of River Mouth Flows

河口流密度界面水力参数及混合过程的时空变化

基本信息

批准号：
62460158
负责人：
YOSHIDA Shizuo
金额：
$ 3.07万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62460158/
关键词：
River mouth LDA Stratified flow Interfacial waves Salt wedge Measurement of turbulence Tidal flow Weak non-linear stability analysis 河口密度流大規模渦河川乱流流速分布二層密度流

项目摘要

In the last year, which ended March 1990, I performed the actual observations, analysis of the new data, and an analysis of the results combined with all data from the past. The observations began on schedule at the Teshio River in the first part of August. However, unfortunately, the weather deteriorated due to a typhoon in the Japan Sea at the time, and Hokkaido was grazed by a low pressure area. Because of the high winds and high waves, we were not able to observe normal two-layer flow. Accordingly, it was impossible to obtain measurements of Reynolds stress in ideal two-layer flow. As the measurements of this year were not performed to satisfaction, we plan to presume this year, and plan to publish a report in 1991. However,, we have obtained following results of major significance in our studies of macroscale problems.The two parameters K and F_d which control fluctuations with respect to physical dimensions and time have been definitively determined. Here K is a comparative index between the average depth at the river mouth and the amplitude of the tide while F_d is the Froude number of the dense flow. When data from observations both past and present is plotted on the K-F_d plane, the conditions governing direction of flow of the river and the occurrence of the three kinds of flow, and the limits of intrusion of salt water are clearly described.During the final year of this program using nonlinear stability analysis, we clarified the growth of interfacial waves, a clue to the explanation of interfacial phenomena, to the weakly nonlinear stage. Results of the analysis showed that transformations in the interface were brought about by instabilities in the flows immediately above and below the interface, that these register as interfacial waves, and that the resulting theoretical streamline structure matches nearly perfectly with the observed one.

在截至1990年3月的去年，我进行了实际观察结果，对新数据的分析以及对结果的分析以及过去的所有数据。 8月第一部分，观察结果是按计划在Teshio河上开始的。但是，不幸的是，当时由于日本海的台风而导致的天气恶化，而北海道则被低压区域所放牧。由于大风和高波，我们无法观察到正常的两层流。因此，无法在理想的两层流中获得雷诺应力的测量。由于今年的测量结果不是为了满意的，我们计划今年假设，并计划在1991年发布报告。但是，我们在宏观问题的研究中获得了遵循重要意义的结果。这两个参数k k和控制相对于物理维度和时间的波动的F_D已被明确确定。这里的k是河口的平均深度与潮汐幅度之间的比较指数，而f_d是密集流量的弗洛德数量。当从观察结果中绘制了过去和现在的数据，在K-F_D平面上绘制了有关河流流动方向的条件和三种流动的发生，并清楚地描述了盐水侵入的限制。该程序的最后一年使用非线性稳定性分析，我们阐明了界面波的生长，这是对界面现象的解释的线索。分析的结果表明，界面中的转换是由界面上方和下方的流中的不稳定性引起的，这些登记为界面波，而所得的理论流线结构几乎与观察到的结构完全匹配。