Resumen

JIMENEZ-MEDINA, Oscar. General Formulas for Chezy and Manning Coefficients. Tecnol. cienc. agua [online]. 2015, vol.6, n.3, pp.33-38. ISSN 2007-2422.

This article proposes general formulas to evaluate the Chezy and Manning coefficients, CCH and nM; namely, their application to the three possible categories of uniform turbulent flow, where roughness is uniformly distributed and corresponds to the composition of the conduction material. This is different than current formulas that determine CCC and nM only according to relative roughness, ignoring the influence of the Reynolds number, and are therefore conceptually valid only and solely for fully turbulent flow, which corresponds to the zone of complete turbulence or quadratic resistance. The present study uses the flow resistance coefficient which is the basis for hydraulic resistance coefficients (CCH, nM, FD-W), as well as the combined Nikuradse and Prandtl-Von Karman formulas for fully turbulent and smooth turbulent flow and the explicit equation validated by Swamee to calculate the Darcy-Weisbach coefficient. This provides more valid and precise results from the Chezy and Manning coefficients, and therefore better represents actual conditions. It should be noted that turbulent flow is classified by three categories- fully turbulent, transient and smooth- according to the relation between the Reynolds number and relative roughness.

Palabras llave : Flow resistance; Chezy and Manning coefficients.

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