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Studies on the laws for sand transport in bed load by waves, winds and currents

波浪、风、流对底质输沙规律的研究

基本信息

批准号：
62420040
负责人：
TSUCHIYA Yoshito
金额：
$ 12.61万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
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/grant/KAKENHI-PROJECT-62420040/
关键词：
Bed load Sand drift Blown sand Sand transport rate Sediment transport Threshold of sand movement Dynamic response Two-phase flow 流砂漂砂量飛砂量流砂量砂粒の応答特性掃流漂砂飛砂・流砂量測

项目摘要

In this study, theoretical investigations of the laws for sand transport in bed load by waves, winds and currents were made in order to unify the mechanism of sand transport by these actions. The main results are:1) A theory of the dynamical response of sand grains to turbulence was proposed taking into account the virtual mass and uplift forces due to the shear effect. The dynamical response characteristics of sand grains to turbulence in air and water were solved. By this theory, the threshold of sand movement by waves, winds and currents were dynamically formulated and the theoretical results were in good agreement with experimental ones.2) The dynamics of motion of a sand grain as saltation or sliding by waves, winds and currents was established. The characteristics of the sand grain motion were obtained. The influence of the virtual mass force and wave acceleration force were made clear.3) In the saltation the mechanism of collision of a saltating sand grain to the granular bed wa … More s dynamically formulated both in uniform and graded sand. By the theoretical result, the influence of the distribution of graded sand on the transport rate of graded sand in blown sand was well explained with experimental and field data of sand transport.4) By applying the momentum conservation law in a saltation layer, the law for sand transport rates was theoretically formulated in the uniform condition introducing the saltation characteristics. The formulas agree well with experimental data of sand transport.5) In order to extend the law for sand transport rates in the uniform condition to that in the unsteady condition, the governing equations of sand -fluid two-phase systems were derived. By integrating it over the waterdepth from the bottom to the water surface, the conservation equations of sand transport rates were obtained. The equations are one of the generalized expression of sand transport rates and may be extended as the basic theory of sand transport by waves, winds and currents. Less

本文从理论上探讨了波浪、风、流作用下推移质输沙的规律，以期统一波浪、风、流作用下推移质输沙的机理。主要研究结果如下：（1）提出了考虑剪切效应引起的上举力和虚拟质量的沙粒对湍流的动力响应理论。求解了沙粒在空气和水中对湍流的动力响应特性。利用该理论，建立了沙粒在波浪、风和水流作用下跃移或滑动的动力学方程，并与实验结果进行了比较，两者吻合较好。得到了沙粒的运动特性。3）在跃移过程中，跃移沙粒与颗粒床的碰撞机制是由颗粒床的运动和运动引起的 ...更多信息在均匀砂和级配砂中动态配制。根据理论结果，结合输沙试验和现场实测数据，较好地解释了级配砂分布对级配砂在风沙中输沙率的影响。4）应用跃移层动量守恒定律，从理论上推导了均匀条件下引入跃移特性的输沙率规律。5）为了将均匀条件下的输沙规律推广到非稳态条件下，推导了泥沙-流体两相系统的控制方程。通过对输沙率在水深上的积分，得到了输沙率守恒方程。该方程是输沙率的普遍表达式之一，可推广为波、风、流输沙的基本理论。少