Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
ON THE ORGANIZED ROUGHT ELEMENTS DISTRIBUTIONS AND THE DRAG REDUCTION EFFECTS OF TURBULENT FLOWS IN PIPES
Submission Author:
Cecília Mageski Madeira Santos , RJ , Brazil
Co-Authors:
Daniel Onofre Almeida Cruz, Atila Pantaleão Silva Freire, Juliana Loureiro, hamidreza anbarlooei
Presenter: Cecília Mageski Madeira Santos
doi://10.26678/ABCM.ENCIT2016.CIT2016-0462
Abstract
Predicting the friction force exerted on a surface due to turbulent flow over it, is an important factor in different engineering disciplines such as piping and atmospheric studies. In practical applications and scientific researches, the distribution of rough elements over the surface is usually considered as random. For such a distribution, there are well recognized empirical friction equations such as Colebrook and also established physical theories. However, their applicability on organized roughness distribution, the case the shape and spacing between the rough elements are not random, is under question. In the present work, the effect of the organized roughness distribution on the turbulent friction factor of a Newtonian fluid is investigated. For this purpose, 4 different roughness configurations (smooth, random distribution and two organized ones) are studied in the pipe geometry. It is observed that for specific organized configurations, the well-known plateau of fully rough regime observed for random distribution of rough elements will disappear. As observed for here, int the mentioned configurations the friction factor will decrease by increasing Reynolds number, with same slope as in the inertial range (Blasius range), indicating drag reduction.
Keywords
Turbulence, Roughness, Newtonian Fluid, Friction Factor, drag reduction, Turbulence, Roughness, Newtonian Fluid, Friction Factor, drag reduction, Turbulence, drag reduction, Pipe Flow, Organized Roughness, Turbulence, Roughness, Newtonian Fluid, Friction Factor, drag reduction, Pipe Flow, Organized Roughness
