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International Journal of Fluid Mechanics Research
ESCI SJR: 0.206 SNIP: 0.446 CiteScore™: 0.5

ISSN Печать: 2152-5102
ISSN Онлайн: 2152-5110

Выпуски:
Том 46, 2019 Том 45, 2018 Том 44, 2017 Том 43, 2016 Том 42, 2015 Том 41, 2014 Том 40, 2013 Том 39, 2012 Том 38, 2011 Том 37, 2010 Том 36, 2009 Том 35, 2008 Том 34, 2007 Том 33, 2006 Том 32, 2005 Том 31, 2004 Том 30, 2003 Том 29, 2002 Том 28, 2001 Том 27, 2000 Том 26, 1999 Том 25, 1998 Том 24, 1997 Том 23, 1996 Том 22, 1995

International Journal of Fluid Mechanics Research

DOI: 10.1615/InterJFluidMechRes.v25.i1-3.180
pages 212-219

Rough-Wall Heat Transfer in Tbrbulent Boundary Layers

M. H. Hosni
Department of Mechanical Engineering, Kansas State University, Manhattan, USA
H. W. Coleman
Mechanical Engineering Department, University of Alabama in Huntsville, Huntsville, USA
Robert P. Taylor
Mechanical Engineering Department, Mississippi State University, Mississippi State, MS, USA 39762

Краткое описание

Measurements for heat transfer in the rough wall turbulent boundary layers are presented. This paper summarizes the previous experimental results for six test surfaces five rough and one smooth. Three of the rough surfaces are smooth plates roughened with hemispherical elements uniformly distributed 2, 4, and 10 base diameters apart. The remaining two rough surfaces are smooth plates roughened with truncated, right circular cones uniformly distributed 2 and 4 base diameters apart. Both of the roughness geometries hemispheres and truncated cones have a 1.27 mm base diameter and a roughness height of 0.635 mm. The Stanton number data are for zero pressure gradient incompressible turbulent boundary layer air flow for several freestream velocities ranging from 6 to 66 m/s which cover the aerodynamically smooth transitionally rough and fully rough flow regimes. These data are compared with previously published results from another similar test facility using a rough surface comprised of spheres of a single size (1.27 mm diameter) packed in the most dense array. It is shown that data for a given rough surface viewed in Stanton number versus enthalpy thickness coordinates do not collapse to a single curve in the fully rough regime as had been postulated based on observations of a single set of rough wall data. The heat transfer data also show that for a given surface Stanton number data in Rex, coordinates approach an asymptotic curve as freestream velocity is increased, becoming a function of Rex, alone (as in the case for smooth wall turbulent flows). However, there is a different asymptotic St-Rex curve for each rough surface, with Stanton number at a given Rex, increasing with decreasing roughness spacing, that is as the surface becomes "rougher". The data also show a measurable difference in Stanton numbers due to roughness elements shape effects.


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