An experimental investigation of the combined effects of surface curvature and streamwise pressure gradients both in laminar and turbulent flows

Abstract

Flow and heat transfer characteristics over flat, concave and convex surfaces have been investigated in a low speed wind tunnel in the presence of adverse and fa- vourable pressure gradients (k), for a range of -3.6 · 10 -6 £ k £ +3.6 · 10 -6 . The laminar near zero pressure gra- dient flow, with an initial momentum thickness Reynolds number of 200, showed that concave wall boundary layer was thinner and heat transfer coefficients were almost 2 fold of flat plate values. Whereas for the same flow con- dition, thicker boundary layer and 35% less heat transfer coefficients of the convex wall were recorded with an earlier transition. Accelerating laminar flows caused also thinner boundary layers and an augmentation in heat transfer values by 28%, 35% and 16% for the flat, concave