Author(s): J. Aguirre-Pe; R. Fuentes
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Keywords: No Keywords
Abstract: In this paper, it is verified that the Shields criterion, for initiation of particle movement on the bed of a channel, is not applicable when the ratio of flow depth to bed particle diameter is less than 10. In the present work, a critical Froude number of the particles, based on a critical mean velocity of flow, is proposed. In the highly irregular flow of steep macro-rough streams, a wake region of assume d constant velocity, close to the boundary composed of loose particles whose size is of the same order of magnitude as the deph of the flow, is considered. The critical Froude number of the'particles was obtained after calibration with available laboratory data. The proposed criterion is compared with other formulations which consider criteria of critical shear stress, critical mean velocity or critical discharge.
Year: 1991