variavel0=<b>Mila Rosendal Avelino</b> - milara@uol.com.br UERJ
<b>Claudio de Castro Pellegrine</b> - pelle@funrei.br FUNREI
<b>Abstract.</b> In the present work, turbulent transfer of momentum and heat over rough surfaces are described in terms of the roughness geometry using functions of the law of the wall for the velocity and for the temperature fields. The effects of sudden changes are predicted in the case of a turbulent flow around surface-mounted two -dim ensional ribs when subjected to a sudden change in surface roughness. A particular interest of this study is to investigate temperature distributions in terms of velocity distributions. Three different surface roughness geometries were considered to simulate velocity and thermal boundary layer flows. The behavior of the displacement in origin for the velocity and the temperature fields is investigated. Wall functions that take into account characteristic parameters of the surface roughness are used to describe the behavior of the velocity and temperature profiles over different types of rough surfaces. Four configurations are simulated here, namely one extensive uniformly smooth surface, that is taken as a reference case, and three characteristic types of rough surfaces. In all the cases, the velocity boundary layer reaches a hot surface, where the thermal boundary layer flow initiates. Experimental measurements are presented for velocity and temperature profiles, for the different surfaces considered. The results show that for the roughness function, an analogy between the velocity and the thermal fields can be obtained.
<b>Keywords.</b> experimental methods, boundary layer, turbulence, roughness, law of the wall.