Study on Unequilibrium Sediment Transport Rate and Local Scour around Structures

建筑物周围不平衡输沙率与局部冲刷研究

• 批准号: 61550365
• 负责人: SAWAMOTO Masaki
• 金额: $ 1.09万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61550365/
• 关键词: Local scour; Cylinder; Wave; Sand Drift; 非平衡性漂砂量

Following three items were studied.1) Dynamic roll of nonequilibrium of sediment transport on bottom topography change under the wave action: The stability of sand bed was analysed theoretically. It was confirmed that the nonequilibrium of sand transport and scattering of step length are necessary for existance of single dominant length of bottom topograpy although asymmetry of sand transport rate make the bed unstable. The results were reported in the first reference.2) Sediment transport rate in sheet flow regime: A series of experiment on sediment transport phenomena were carried out in sheet flow regime using an U-shape tube. Sediment transport rate, sediment motion and velocity distributions were measured. The 1.5 power relationship between transport rate and the bed shear stress was concluded. The limit of sheet flow regim was also discussed. The results were reported in the second reference.3) Local scour around a cylinder under the wave action: A series of experiments were performed in a wave tank. The observed shapes of scour were classified into two category. The mechanism of scour was discussed considering the interaction of the flow and the bed. The roll of shedded vortices was confirmed through the flow visualization technique.

研究了三个项目。1）在波动作用下，在底部地形变化上，沉积物传输的非平衡动态卷：理论上分析了沙床的稳定性。已经证实，尽管沙子传输速率的不对称性使床不稳定，但对于存在单个底部托架的单个显性长度，砂长的散布的非平衡对于存在底部的单个底层长度是必需的。结果是在第一个参考文献中报告的。2）板流量方案中的沉积物传输速率：使用U形管在板流方向上进行了一系列关于沉积物传输现象的实验。测量了沉积物传输速率，沉积物运动和速度分布。结束了运输速率和床剪应力之间的1.5功率关系。还讨论了板流方案的极限。在第二个参考文献中报告了结果。3）波动作用下的圆柱周围的局部气泡：在波罐中进行了一系列实验。观察到的冲刷形状分为两类。考虑了流动与床的相互作用，讨论了冲刷机制。通过流动可视化技术证实了脱落的涡旋卷。

项目成果

Sawamoto,M.: "Sediment Transport in Sheet Floe Ragime" "Coastal Sediment'87", WW Div./SCE. 415-423 (1987)

Sawamoto,M.：“片状浮冰 Ragime 中的沉积物输送”“沿海沉积物 87”，WW Div./SCE。

Nishizawa,M.: Proc.of 6th APD-IAHR Congress. (1988)

Nishizawa,M.：第六届 APD-IAHR 大会议程。

Sawamoto,M;Yamashita,Y: Coastal Sediment 87'. (1987)

泽本，M；山下，Y：沿海沉积物 87。