The Effects of Free-Stream Turbulence and Flow Pulsation on Heat Transfer From a Cylinder in Crossflow

Abstract

The heat transfer from a circular cylinder is a fundamental problem with practical applications ranging from tubular heat exchangers to the leading edge of gas turbine blades. The flow field across the surface is often unsteady due to natural instabilities or forced oscillations of the fluid. Examples are the periodic natural shedding of vortices form cylinders and the wakes of rotor blades in gas turbine engines. In addition, active vibration of the fluid is a possible means of augmenting the heat transfer. When the frequencies are near the natural shedding frequency of the cylinder, active fluid vibration also gives the possibility of frequency control through lock-on. The present work is an experimental study of the combined effects of flow pulsation and turbulence on the local heat transfer from a circular cylinder. In particular, the possibility of a coupling between the two effects is investigated.