摘要
针对平原河道糙率计算方法,探讨受潮汐影响的宽浅河段糙率计算。以长江河口段为例,分析潮周期内流量变化过程以及流速沿水深分布特征,选取落潮稳定时段,利用流速垂线分布特征及Einsten断面综合糙率计算方法计算河道糙率。利用明渠非恒定流圣维南方程,推算涨落潮历时过程中计算河段逐时河道糙率n,分析非恒定流量变化d Q/dt对糙率影响,反映了潮汐河段河道糙率变化特征,分析其落潮过程中,随水位降落洲滩水深植被等影响下河道糙率的变化情况,采用落潮稳定期天然实测资料,进行代表性断面测点垂线流速分布特征,综合糙率计算法和河道水力计算推求糙率法,分析确定河道糙率。
The roughness rate of river course is an important basic parameter in hydraulic calculation of hydraulic engineering design and model test. In this paper, based on the method of calculating the roughness of plain channel, the roughness affected by tides is discussed. Taking the estuary- section of the Yangtze River as an example, the flow change process and the distribution characteristics of flow velocity along the depth of water are analyzed. Stable ebb period is selected as research example, using the velocity characteristics of vertical distribution and comprehensive roughness calculation method of Einsten section to calculate the river roughness. Using the unsteady flow of open channel saint - venant equation, the hourly channel roughness n is calculated in tidal process. The influence of unsteady flow change dQ/dt on roughness rate is analyzed, which reflects the variation characteristics of roughness rate in tidal channel. The variation of river roughness under the influenee of water level, water depth, vegetation and other factors in the process of the ebb is analyzed. Based on the measured data of the steady period of the ebb tide, the comprehensive roughness rate calculation method of the velocity distribution characteristics of the vertical line at the measuring point of the section and the hydraulic calculation and deductive roughness rate method of the river are carried out to analyze and determine the roughness rate of the river.
作者
夏明嫣
XIA Mingyan(The College of Hydraulic Science and Engineering,Yangzhou University,Yangzliou 225009,Chin)
出处
《广东水利水电》
2018年第8期32-35,64,共5页
Guangdong Water Resources and Hydropower
关键词
河道糙率
潮汐河段
非恒定流
水力计算
垂线流速分布特征
river roughness
tidal reach
unsteady flow
hydraulic calculation
vertical velocity distribution characteristics
