SIQUEIRA, M. T.; SIQUEIRA, Marcos Tibério de.
Résumé:
The principal objective o f this work is to verify the influence of sediment size
distribution about transport and resistance in alluvial channels. Data were gathered in
experiments using a completely automatic recirculation channel with three sediment
mixtures, uni modal and log-normal, that had the same median diameter D 5 0 (0,38 mm)
and different size distribution. It was also postulated the possibility there be a
representative diameter, different than median diameter, for each size distribution
studied. For this purpose were selected the following transport equations: Einstein
(1950), Bagnold (1966), Laursen (1958) and Yang (1973), to calculate the sediment
transport rates.
Taking into account the transport and resistance to the flow, the non uniform
mixtures, in identical flow conditions, shown smaller transport rates and larger
resistance values than the most uniform mixture.
The results got with the transport equations, when were used different diameters
than median diameter, didn't differ too much than the results with D50, it means that
only small adjustment in the transport rates were obtained.