HR: 0800h
AN: H51I-0897    [Abstracts]
TI: Impedance-Based Measurement of Suspended Sediment Concentrations
AU: * Beninati, M L
EM: m.laura.beninati@bucknell.edu
AF: Department of Mechanical Engineering, Bucknell University, Moore Avenue, Lewisburg, PA 17837, United States
AU: Shea, A
AF: Department of Mechanical Engineering, Bucknell University, Moore Avenue, Lewisburg, PA 17837, United States
AU: Long, B R
AF: Department of Geosciences, The Pennsylvania State University, College of Earth and Mineral Sciences, State College, PA 16801, United States
AB: A new technique for measuring suspended sediment concentration and range of particle grain sizes is being developed for field use. Suspended sediment flows are multi-phase flows commonly found in river and marine environments. Recent environmental concerns have drawn attention to the mechanism of contaminant transport associated with the erosion and deposition of suspended sediment. Unfortunately existing theoretical models of sediment transport lack solid empirical validation due in part to the difficulty involved in the accurate field measurement and characterization of these multi-phase flows. Of particular interest is the suspended sediment concentration which can vary spatially as well as temporally. While there are several methods available presently to estimate sediment concentration such as: acoustic back scattering, optical back scattering, laser diffraction and remote spectral reflectance, none entirely meet the need for simple, reliable laboratory and field measurement of suspended sediment concentrations. The measurement method proposed herein consists of an electrical based measurement yielding complex impedance as a function of frequency which in turn can be related to a dielectric mixing function for the suspended sediment and water. Prior electrical measurement efforts are limited to scalar conductivity measurements often at a single frequency. The two-phase mixture used for this study is sediment and water, where the grains are held in constant suspension by a mechanical stirring. Variables such as: sediment classification, particle grain size, mixture temperature, and temporal dependence have all been parametrically studied and their effects on the measurement system documented. This data will be used to develop a series of dielectric mixing equations which correlate multi-flow vector impedance measurements to suspended sediment concentration, through electrical properties of the mixture.
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: 2007 Fall Meeting