代表垂线平均流速与断面平均流速关系分析

Analysis of Relationship of Average Flow Velocity in the Representative Vertical Line and Section

以杨家营水文站垂线平均流速、断面平均流速实测资料为例，采用建立垂线平均流速与断面平均流速相关关系曲线的方法，在通过定线精度检验的基础上，来确定施测断面平均流速的代表流速垂线，以简化施测断面平均流速的技术手段。采用代表垂线法施测断面平均流速，可将多条测速垂线简化至1条，故此实测断面平均流速的总历时可成倍缩短，这无疑保证了抢测洪水流量过程（尤其是峰谷转折点）的测验时机。即采用代表垂线法施测断面平均流速可达到即时控制洪水流量的剧烈变化过程、确保一次测流允许的水位涨落差不大于平均水深的10％和减轻测验劳动强度的目的。

Taking the average flow velocity measurement data in vertical line and in section of Yangjiaying hydrological station as example, based on accuracy testing in the line, this article confirms the representative flow vertical line for surveying average flow velocity in section. It establi-shes correlation relationship curve between average flow velocity in vertical line and in section, to simplify technical means of surveying the aver-age flow velocity in section. Because it can simplify velocity measurement vertical lines to one, it can doubly shorten the duration of measured av- erage flow velocity in section. It guarantees the opportunity of measuring flood flow （especially on the turning point of peak-valley）. For this method it can immediately control violent change process of flood flow to ensure water level fluctuation fall no more than ten percent of average water depth, and reduce the measurement labor intensity.