渠道糙率率定误差分析

本文研究了渠道糙率率定误差与水力测量误差的函数关系。根据水力学原理,提出了计算渠道糙率率定误差的公式,然后计算分析了南水北调中线京石段应急供水工程实测流量、水深误差产生的渠道糙率率定的误差.得到重要结论:(1)微小的水力测量误差可能产生较大的渠道糙率率定误差,现有南水北调中线典型渠道原型观测糙率误差可达11%;(2)糙率的流量误差分量相对值与流量测量误差基本相同;(3)糙率的进出口水深误差分量绝对值非常接近,两者绝对值大小不仅与水深测量误差成正比,而且与渠道长度有关,当渠道过短时,糙率的水深误差分量将成倍增加。

Error analysis of roughness coefficient calibration for channels

This paper studies the relationships between the error of the channel roughness coefficient calibration and that of the hydraulic measurement. According to the principle of hydraulics , the formula of determining the error of the channel roughness coefficient calibration is deduced explicitly. Based upon the measured data from the Beijing-Shijiazhuang Emergency Water Supply Project of South-to-North Water Diversion , the error analysis of the roughness coefficient calibration is carried out for the typical channels. Some important conclusions are attained :( 1 ) tiny hydraulic measurement error may result in significant error of the channel roughness coefficient calibration and for the existing typical channel the error can reach 11% ;( 2 ) the relative error of the roughness coefficient caused by the volumetric discharge is approximatly equal to the error of flow meter ;( 3 ) if the measurement errors of the water depths are the same , the error of the channel roughness coefficient calibration caused by the inlet water depth is very close to that caused by the outlet water depth. When the channel length is short , the error of the channel roughness coefficient calibration will increase significantly.