Three-dimensional sediment transport measurements by acoustics (TRIDISMA)

The MAST III Project “TRIDISMA” was designed to develop and extend the quantitative use of acoustics in studying sediment resuspension processes by incorporating theoretical and experimental evaluation of the inversion and backscattering problem. As part of this objective a prototype acoustic instrument (APRI) has been developed which combines multi-frequency acoustic backscatter, coherent Doppler and acoustic correlation techniques to provide high-resolution measurements of the flow and suspension field. Trials of a laboratory version of the instrument have been undertaken in a large-scale wave and current flume, the results of which are discussed. The findings reported highlight the capability of high frequency acoustics as a tool for resolving the complex interactions that occur between the flow, the suspended sediment and the bed when waves and currents interact and are providing new insights into the fundamental mechanisms of sediment transport