Author(s): Kiyosi Kawanisi; Tomoya Yokoyama; Mahmoud F. Maghrebi
Linked Author(s): Kiyoshi Kawanishi
Keywords: Suspended sediment concentration; Acoustic Doppler velocimeter; Sound scattering; Settling velocity
Abstract: A new method for the measurement of suspended sediment concentration (SSC) is brought forward. Acoustic backscatter and particle velocity obtained from a commercially available acoustic Doppler velocimeter (Vectrino, Nortek AS) can be used to deduce the concentration and size of suspended sediment. The particle size deduced from analyzing its vertical velocity of a Vectrino is accorded well with the mean size of suspended particles. Under high concentration, the attenuation coefficient associated with the scattering of the suspended particles along the sound pass should be considered. Since two parameters (sensitivity and attenuation coefficient) in an acoustic backscatter equation, which expresses the relation between acoustic backscatter intensity and SSC, are expressed as a function of particle size, the Vectrino has the capability of measuring SSC if physical characteristics of the suspended sediment do not change significantly. The experimental results for suspended glass beads, sand, and clay particles showed that SSC deduced from Vectrino data is accorded well with SSC from water samples, even for high concentrations.
Year: 2007