Efecto del número de Froude densimétrico en el transporte de sedimentos

Abstract

In this paper, critical conditions for the initiation of particle motion are considered for ratios depth to bed particle less than 10 (flow on very rough boundaries). Here, a densimetric Froude number of the particles is analysed as an alternative criterion to predict hydraulic conditions for the initiation of motion. Critical densimetric Froude numbers of the particles were determined after calibration with available laboratory data. Some of the most employed formulations to estimate bed material transport in high slope macro-rough flows are described. Most of the theories consider the excess of boundary shear stress, above the critical shear stress, as the dominating parameter that defines sediment transport. Two procedures, that were specifically developed to predict sediment transport in high slope streams, are presented. One of them considers the excess of a dimensionless discharge, above the critical discharge, the second one incorporates the influence of the densimetric Froude number of the particles, in excess of its critical value. A new transport function, that shows a better behavior than the previously analyzed formulations, is proposed in this paper for high slope macro-rough streams.