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Experimental Studies on the Characteristics of Near-bottom Flow in the Current with Waves

含波流近底流特性的实验研究

基本信息

批准号：
06452372
负责人：
SEGUCHI Masahiro
金额：
$ 3.71万
依托单位：
Saga University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

The Summary of this research results is as follows :(1) The steady flow component in the current with waves was theoretically analyzed by using a three-layr eddy viscosity model near the bottom boundary layr. Moreover, a simple method to estimate the important parameters contained in the analytical solution was presented. The analytical solutions almost agreed with the experimental results.(2) The theoretical solution of the wave flow component in the current with waves was obtained by using a two-layr eddy viscosity model, in which the eddy viscosity in the wave boundary layr increased quadratically with the height above the bottom and that outside the wave boundary layr constant. The theoretical and experimental values almost agreed.(3) The analytical values of shear stress in the current with waves were obtained from the theoretical solutions of the steady and wave flow components. The variations of the bottom shear stress with wave phase and the influences of wave motion on the bottom shear stress were clarified from the analytical results of shear stress.(4) The phase difference of the wave flow component in the current with waves inside and outside the wave boundary layr was maximum at the bottom. The maximum value of phase difference ranged between 40ﾟ and 48ﾟ for the present experimental conditions.(5) The resuspension rate of the bottom sediment in the current with waves for the present experimental conditions was about 20% to 30% bigger than that in the current. The variations of the resuspension rate of the bottom sediment with the wave height under a constant velocity were bigger than those with the magnitude of velocity under a constant wave height.

主要研究成果如下：(1)利用底部边界层附近的三层涡粘模型对含波流中的稳态流动分量进行了理论分析。此外，还提出了一种估计解析解中包含的重要参数的简单方法。解析解与实验结果基本吻合。(2)利用双层涡粘模型,得到了含波流中波流分量的理论解,其中波边界层内的涡粘系数随距底部高度和波边界层外的高度呈二次方增加。理论值与实验值基本一致。(3)由稳态流分量和波浪流分量的理论解得到了含波流中剪应力的解析值。从剪应力分析结果中阐明了底部剪应力随波浪相位的变化以及波浪运动对底部剪应力的影响。(4)波边界层内外波流中波流分量的相位差在底部最大。在本实验条件下，相位差的最大值在40°～48°之间。(5)在本实验条件下，有波浪的水流中底部沉积物的再悬浮率比水流中大约20%～30%。等速条件下底泥再悬浮率随波高的变化大于等波高条件下随波速大小的变化。