Unsteady heat transfer and velocity of a cylinder in cross flow—I. Low freestream turbulence

Abstract

This paper is the first of two papers which describe simultaneous measurements of time resolved heat flux and local velocity at the surface of a cylinder in cross flow. Time-averaged Nusselt numbers, heat flux auto spectra and time traces are presented and the coherence and phase difference between the velocity and heat flux signals are used to establish that the heat transfer fluctuations at the front of the cylinder originate in pulsation of the flow field resulting from vortex shedding in the wake. The effect of increased levels of freestream turbulence on the heat transfer fluctuations is explored in Part II of this study.