SECONDARY FLOW MEASUREMENTS IN A RIVER BY A BOAT-MOUNTED ADCP

Abstract

Secondary flow in a river was measured by a boat-mounted Acoustic Doppler Current Profiler. Three methods were tested, i. e., A) measuring in a fixed cross section with single back-and-forth, B) measuring in a fixed cross section with multiple back-and-forth, and C) measuring without fixed sections but randomly in the whole tested area. Reliability of the methods was examined via drawn primary and secondary velocity distributions. Applicability of the methods for a particular purpose was also discussed.
The method A, which is widely used for river discharge estimations, gives primary velocity fairly accurately. The method B gives the best results for secondary flow structure amongst the tested if the estimated time is good enough. The method C shows similar performance in accuracy as the method A, but it has an advantage of covering the whole flow field, even roughly, but with less time and efforts.