Resumen

CONSTAIN-ARAGON, Alfredo; VILLA, Pedro  y  BASTIDAS, Guillermo Andrés. New method to determine mixing length in turbulent flows. Tecnol. cienc. agua [online]. 2013, vol.4, n.4, pp.63-76. ISSN 2007-2422.

The behavior of the distribution of solutes in cross-sections of natural streams is very important to sciences and field techniques pertaining to environmental, sanitary and civil engineering. Today's acute problems place strong pressures on hydraulic resources. Therefore, an in-depth understanding of the phenomena that define the course and impact of water contaminations is increasingly needed. Given the current importance of this subject, many methods and formulas have been developed to determine "mixing length" -the distance at which a substance under study uniformly dissolves in a flow cross-section. Nevertheless, a large majority of these equations are empirical or based on conjectures that are not completed substantiated. Therefore, this article presents an objective approach to the subject of the "degree of mixing" and proposes practical equations to apply to real cases. These equations have a broad scope, making it possible to measure the slope of a channel without using subjective observation, as is commonly done with the Manning procedure. Finally, the application of a salt tracer in a small mountain stream in Colombia is discussed in detail, as interpreted by the new equations, and conclusions and recommendations are presented.

Palabras llave : water quality; mass transport in fluids; complete mixing condition; tracers; hydraulics; turbulent dispersion theory.