Transition to turbulent flow in curved and straight channels with heat transfer at high Dean numbers

Abstract

Heat transfer in a channel with a straight portion followed by a portion with mild curvature, an aspect ratio of 40, and 0.979 radius ratio is studied at Dean numbers from 700–1100. The effects of curvature, streamwise development, Dean number, and flow tripping are illustrated by the data. Important Nusselt number increases occur due to laminar-to-turbulent transitional phenomena in the straight portion of the channel. Downstream of these increases, flow approaches fully turbulent behavior, and Nusselt numbers collect into families of curves which show weak dependence on Dean number and strong dependence on normalized streamwise distance.