Alfredo José Constaín Aragón
I+D+I, FLUVIA, Bogotá, Colombia.

Carlos Peña-Guzmán
Environmental and Sanitary Program, La Salle University, Bogotá, Colombia.

Gina Alexandra Peña-Olarte
Environmental Coordination, FLUVIA, Bogotá, Colombia.

DOI https://doi.org/10.33889/IJMEMS.2020.5.6.101

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Abstract

Mean velocity is a key parameter for understanding, modeling and predicting the complex phenomena of advection and dispersion in natural watercourses, which are threatened by human intervention and river disasters. For this reason, the principles of relative constancy for the value of this parameter, established early by L. Prandtl and L. Leopold in the 20th century, are powerful theoretical tools for those who develop engineering tasks in this field. This article presents updated analyses of these principles, explaining how this constancy depends essentially on the existence of a steady state in the flow, which allows equiprobability in the system, and therefore, a minimum production of entropy. At the same time an equation is developed, as a function of macroscopic parameters, facilitating its interpretation and practical application. This hypothesis is contrasted by reviewing the relative values for those parameters and their effect on the formula, and defining the practical conditions of applicability of the formula. This method of validating the hypothesis is important in hydrometric practice, as flow velocity measurements are the starting point for their description, especially for large rivers where comprehensive assessments are impossible.

Keywords- Turbulence, Thermodynamics of irreversible processes, Production of entropy, Hydraulic.

Citation

Aragón, A. J. C., Peña-Guzmán, C., & Peña-Olarte, G. A. (2020). Foundations of the Relative Constancy of Mean Velocity for Natural Streams: A General Principle of Steady State Anticipated by L. Prandtl and L. Leopold. International Journal of Mathematical, Engineering and Management Sciences, 5(6), 1363-1378. https://doi.org/10.33889/IJMEMS.2020.5.6.101.