Steady and unsteady turbulent velocity profiling in open channel flows using the ADV Vectrino II profiler

Abstract

The Nortek Vectrino II profiler acoustic Doppler velocimeter (ADV) was developed for velocity profiling. Herein, the study aims to 1) demonstrate the applicability of the ADV profiler to steady and rapidly-varied unsteady open channel flows, 2) check the data quality, based upon a new systematically comparative analysis with traditional ADV data, and 3) conduct a sensitivity analysis on ensemble-averaged data collection in a positive surge. This was achieved by systematically performing steady and unsteady velocity measurements under controlled flow conditions in a relatively large laboratory facility. All experiments were repeated 25 to 50 times for each controlled flow condition and the results were ensembleaveraged. Steady and unsteady velocity measurements highlighted a number of instrumental errors using the ADV Profiler. Overall, the study demonstrated that the propagation of positive surges was a highly unsteady turbulent process, and the performance of ADV Profiler in such an unsteady turbulent flow could be satisfactory provided that careful validation was undertaken for all ADV Profiler outputs.