采用流管元测量冰期流量及流速分布的方法

A novel technique for flow discharge and depth-averaged streamwise velocity in ice periods based on stream tube methods

北方河流冰期测流需要在冰盖上沿断面打孔,再测量各孔垂线流速分布,最后通过流速积分得到冰盖下的总流量。这种传统的冰期测流是一项耗时耗力且高风险的工作,限制了冰期流量流速资料的采集。本文基于流管元法和爱因斯坦的断面分区方法,提出一种基于理论公式的冰期测流方法。该方法被用于实验条件下复式断面的流速分布和黄河不同断面的流量计算。结果显示新方法获得的断面流量、单宽流量分布和水深平均的流速分布与实验值和现场观测值符合良好。基于流管元的冰期测流方法能广泛用于明流、部分冰封和完全冰封河道断面的流量及流速分布测量,能有效减少冰期测流工作量、提高测量效率,进而减少测量人员安全风险,可在水文观测中推广应用。

Field discharge observation in ice periods is extremely difficult and highly risky.Traditionally,it needs to dig holes along the cross section on the ice cover,to gauge velocity distributions along the flow depth at each hole,and to calculate the cross-sectional flow discharge by integrating velocity profiles over the whole area.The traditional method is time-consuming,costly,and inefficient,which greatly limits the field flow measurements during the ice period.To fill such gap,a new technique is proposed in this paper for flow discharge measurement in ice periods in support of the stream tube method and Einstein’s splitting method for cross sections.The new technique is applied to the calculation of depth-averaged streamwise velocity profile in experimental compound flume and the evaluation of the field flow discharge in the Yellow River at various cross sections.The results show that the new method works well in estimating flow discharge,unit discharge distributions,and depth-averaged velocity distributions in both fully and partially ice-covered flows.The new technique is efficient,time-saving and accurate,decreasing the gauging risk of operations.It might be further applied to field hydrological observations in open,partially and fully ice-covered flows.