Author(s): A. M. Ferreira Da Silva; A. D. Binns
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Abstract: This paper is intended as a contribution towards the evaluation of the resistance factor of natural alluvial meandering streams. The well-known “divided resistance” approach commonly adopted nowadays for straight streams with a bed covered by dunes and/or ripples is extended to include the additional resistance due to the meandering of the stream. The considerations are developed with the aid of all the data available to the writers. It is found that the contribution of the meandering of the stream to its overall resistance can vary from negligible to very substantial, depending on the stream geometric and flow conditions: negligible in small and large sinuosity streams having large values of the width-to-depth ratio, and very substantial in streams having intermediate values of sinuosity and values of width-to-depth ratio less than ≈ 25, say. The results are explained in view of the present understanding of the mechanical structure of meandering flows.
Year: 2009