Vectrino Profiler在明渠紊流测量中的适用性研究

为测试声学多普勒流速仪(ADV)在明渠紊流测量中的适用性,在水槽中进行了系列试验,重点研究采样频率及安装高度对测量结果的影响。试验中使用诺泰克公司(Nortek)生产的新型ADV产品Vectrino Profiler及清华大学研制的PIV系统对水流同步测量。测量结果的对比分析显示,该型号ADV有如下特点:(1)存在准确度最优点,位于探头正下方约5 cm处;(2)采样频率对流速时均值的影响可忽略不计,对紊动参数的影响很大;(3)Vectrino Profiler在紊动参数的测量中,只有在优点处的计算结果较为可靠,最优点外数据可信度不高;(4)当测量区域靠近水面或床面时,测量误差都会变大。本文研究结果表明,在将Vectrino Profiler用于明渠紊流测量时,需要合理选定测量频率和探头安装位置,否则可能会导致错误结果。

Applicability of Vectrino Profiler in measurement of open channel flows

Experiments were conducted in a hydraulic flume to test the applicability of the Vectrino profiler, a Nortek ADV velocimetry, in measurement of turbulent open channel flows at different sampling frequencies and operation heights. A typical PIV system was adopted to provide simultaneous measurements as benchmark. The results indicate that 1) a sweet point of 5cm below the profiler probe was detected at which two measurements agree well; 2) sampling frequency has little influence on the time-averages of ADV measured velocities, but its influence on turbulent parameters is significant; 3) beyond the sweet point, the reliability of ADV measured turbulent parameters is not good; 4) the performance of the Vectrino profiler becomes poor in the regions near water surface and channel bed. Thus, sampling frequency and operation height should be carefully determined for measurement of open channel turbulences using a Vectrino profiler.