Author(s): A. Radice; F. Ballio
Keywords: No Keywords
Abstract: The manuscript presents results obtained from two long-duration experiments of one-dimensional bed load. The tests were run in a pressurized duct having rectangular cross section. The experimental conditions corresponded to weak sediment transport, as the ratio of the mean water velocity to the threshold value was equal to 1. 03 and 1. 11. The spatial distribution of the concentration of moving sediments was measured by means of image processing. The concentration values were measured at a frequency of 25 Hz which, combined with a duration of almost half an hour, provided a large amount of data for a robust statistical analysis. Processing of the sediment concentration data involved (i) an analysis of the statistical moments of the temporal samples, (ii) an analysis of the intermittency and (iii) spatial and temporal correlation statistics. The experimental results are discussed in light of a conceptual picture of the sediment transport being driven by the coherent turbulent events in the near-bed boundary layer.