水文测验中两种测速垂线精简算法比较研究

随着中小河流治理项目的推进,改革水文测验方式,探索测流方式方法技术创新势在必行。本研究依托南京信息工程大学学生水文测验教学实习过程中组织开展的2次测速垂线优化精简实验,收集了渔梁水文站2次多测速垂线流量测验数据,针对原精简算法在流量误差最小的寻优过程中可能删去最有代表性的垂线这一问题,设计了直接寻求流量误差最小的测速垂线组合的新算法,并深入分析了两种精简算法对流量误差的影响。结果表明:测站目前采用的常测法选取的13根固定垂线代表性较好,流量测验精度较高;对比原算法,新的垂线精简算法在相同垂线数目下,流量误差更小,测验精度更高;由新算法,特殊水情下单垂线测流可考虑将垂线位置布设在起点距84 m处;流量相对误差大小随着优选垂线数量的增加呈指数递减规律。本研究所提的垂线精简算法有助于提高实验的精度,可为基层水文站开展垂线精简分析工作,进行测流方式改革提供参考。

Comparison of two reduction algorithms of velocity measuring vertical lines in hydrometry

With the implementation of the medium and small-sized river harnessing projects, it is necessary to reform hydrometry methodology and explore technological innovation for flow measurement. Thus, two optimization experiments for velocity measuring vertical lines were implemented by hydrometeorology undergraduates of Nanjing University of Information Science and Technology in this study. The measuring velocity data of multi-vertical lines of the two experiments in Yuliang hydrologic station were collected. Since the original reduction algorithm was likely to omit the most representative vertical line in the process of searching for the optimal flow error, a new algorithm was designed to directly search the vertical lines of the minimal flow error. Then the impacts of the two algorithms on flow errors were analyzed. The results showed that: the 13 vertical lines selected by the constant velocity measuring method were proved to be well representative. They could be used to calculate discharge with high accuracy in current survey. The new algorithm uses the same number of vertical lines, but with smaller flow errors. According to the results of the new algorithm, the single vertical line located at 84m apart from the starting point may be considered as a simple scheme for single vertical line flow measurement in the case of specific hydrologic circumstance. The flow relative error presented an obvious exponential decreasing tendency as the increase of the selected vertical lines. The reduction algorithm of this research is beneficial to enhancing the experiment accuracy. The results offer reference for the daily work of vertical lines reduction and the reformation of flow measuring method for the basic hydrologic stations.