榆树沟水文站输沙率与流量异步施测法分析

在悬移质输沙率与流量异步施测法基本原理分析的基础上,根据河流特性建立了多年综合及相邻流量测次累积面积百分数与累积流量百分数相关曲线法不同的部分流量权重系数借用方案。经实测资料检验,输沙率与流量异步施测法的计算误差符合《河流悬移质泥沙测验规范》精度要求,能满足悬移质泥沙测验的需求。

运用正交数值网格计算平面二维河道推移质冲淤

本文对平面二维非均匀推移质冲淤计算进行了研究,针对推移质输沙带具有靠近弯道凸岸、一般不进入回流区的特点,采用文献[1]的数值网格生成方法和流场计算方法,生成在凸岸密集、在立轴回流区稀疏的正交数值网格和计算流场,既可节省计算时间和内存,又能提高推移质冲淤计算精度,运用文献[2]的“可动层”概念,提出床面“可动层”泥沙级配计算方法,考虑了床沙级配随冲积层深度的变化,文中以长江重庆九龙坡弯道河段正态模型为例,计算了非均匀推移质冲淤河床变形,其结果与实测资料基本一致,

Time-Dependent Sediment Transport Subjected to Downward Seepage

Experiments were conducted using cohesionless sand particles with median diameter of 0.48 mm to investigate the time variation of sediment transport rate under the influence of local downward seepage.The experimental results show that the bedload transport rate in terms of volumetric sediment transport rate per unit width increased rapidly with time in the presence of suction,eventually reaching a peak beyond which it started to decrease.The trend of reduction was significantly reduced beyond 8 400 s after the test started.The analytical expression was derived in terms of dimensionless sediment transport rate and dimensionless time.The hypothesized relationships were compared with the experimental data,indicating a good agreement with each other.