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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Acoustic mapping velocimetry proof-of-concept experiment
Acoustic mapping velocimetry proof-of-concept experiment
Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance
in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both
suspended and bedload estimation. While the measurement of suspended load is currently an active area of testing with
non-intrusive technologies (optical and acoustic), bedload measurement does not mark a similar progress. This paper
describes an innovative combination of measurements techniques and analysis protocols that establishes the proof-ofconcept
for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bedload
using non-intrusive measurements acquired in rivers developing bedforms.
The raw information for AMV is collected with acoustic multi-beam technology that in turn provides maps of the river
bathymetry over swaths of the river cross-section (acoustic mapping). As long as the acoustic maps can be acquired
relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bedforms, the
acoustic maps can capture continuously the progression of the bedform movement. Conversion of the bed elevation maps
in homologous gray-level ˇ°imagesˇ± followed by application of particle image velocimetry concepts to the obtained maps
allow quantification of the bedform dynamics as two-dimensional velocity maps superposed on the streambed plane.
Furthermore, use of the velocity fields in conjunction with conventional analytical methods for estimation of the bed
movement (e.g., Exner equation) enable estimation of bedload rates over the whole imaged area in any direction. The
technique represents a promising approach for in-situ measurement of the bedform dynamics either as a distribution of
bedload rates over the stream cross section or as a bulk bedload rate in the streamwise direction, as typically requested in
most of the practical applications.
File Size : 2,796,991 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 12/08/2015
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