Library Subscription: Guest
ICHMT DL Home Current Year Archives Executive Committee International Centre for Heat and Mass Transfer

Post Roughness Dominant Regime in the Turbulent Flow Through Rough Pipes

DOI: 10.1615/THMT-18.1200
pages 1061-1063

C.M.M. Santos
Mechanical Engineering Program, Federal University of Rio de Janeiro, Brazil

H. R. Anbarlooei
Mechanical Engineering Program (PEM/COPPE), Universidade Federal do Rio de Janeiro, C.P. 68503, 21941-972, Rio de Janeiro, Brazil

D. O. A. Cruz
Mechanical Engineering Department, Federal University of Rio de Janeiro, Av. Moniz de Aragao 420, 21945-972 Rio de Janeiro, Brazil

F. Ramos
Department of Applied Mathematics, Institute of Mathematics, Federal University of Rio de Janeiro, Brazil


The influence of the surface roughness on the turbulence structures has been studied extensively experimentally and numerically. It is well known that in addition to the size of the rough elements, their spatial distribution also affects the turbulence. Pioneering study of Nikuradse showed that the turbulence in not affected in Laminar, transitional and early turbulent regimes by presence of the roughness and this effect just becomes dominant only at high Reynolds numbers.
In the present work, the effect of the roughness geometry (height and spatial distribution) on the friction factor is experimentally investigated. Our main goal was to acquire data of carefully defined rough surfaces for further analytical and theoretical studies. However, unexpectedly, our results show that at high enough Reynolds number the classically fully rough regimes (constant friction factor) ends and normal smooth behaviour resumes. To our knowledge such a phenomenon has not been mentioned in the literature before.

ICHMT Digital Library

Bow shocks on a jet-like solid body shape. Thermal Sciences 2004, 2004. Pulsed, supersonic fuel jets - their characteristics and potential for improved diesel engine injection. PULSED, SUPERSONIC FUEL JETS - THEIR CHARACTERISTICS AND POTENTIAL FOR IMPROVED DIESEL ENGINE INJECTION
View of engine compartment components (left). Plots of temperature distributions in centreplane, forward of engine (right). CHT-04 - Advances in Computational Heat Transfer III, 2004. Devel... DEVELOPMENT AND CURRENT STATUS OF INDUSTRIAL THERMOFLUIDS CFD ANALYSIS
Pratt & Whitney's F-135 Joint Strike Fighter Engine under test in Florida is a 3600F class jet engine. TURBINE-09, 2009. Turbine airfoil leading edge stagnation aerodynamics and heat transfe... TURBINE AIRFOIL LEADING EDGE STAGNATION AERODYNAMICS AND HEAT TRANSFER - A REVIEW
Refractive index reconstructed field. (a) Second iteration. (b) Fourth iteration. Radiative Transfer - VI, 2010. Theoretical development for refractive index reconstruction from a radiative ... THEORETICAL DEVELOPMENT FOR REFRACTIVE INDEX RECONSTRUCTION FROM A RADIATIVE TRANSFER EQUATION-BASED ALGORITHM
Two inclusion test, four collimated sources. Radiative Transfer - VI, 2010. New developments in frequency domain optical tomography. Part II. Application with a L-BFGS associated to an inexa... NEW DEVELOPMENTS IN FREQUENCY DOMAIN OPTICAL TOMOGRAPHY. PART II. APPLICATION WITH A L-BFGS ASSOCIATED TO AN INEXACT LINE SEARCH