Some Results on the Heat Transfer Within Resonant Cavities at Subsonic and Supersonic Mach Numbers

Abstract

An experimental investigation of the heat transfer within two cavities (L/D = 1.25 and 2.0) exhibiting self-induced pressure oscillations (commonly referred to as resonance) is discussed. The tests were conducted with free stream Mach numbers between 0.35 and 1.5 with corresponding unit Reynolds numbers of 33 × 105 /ft to 41 × 105 /ft. The approaching boundary layer and shear layer over the cavitieswere turbulent at all times. The pattern for the heat transfer coefficient distribution over the cavity walls is in good agreement with that found by other investigators. The effect of the self-induced pressure oscillations, however, is to cause large changes in the level of the heat transfer, with low values occurring at the distinctive peaks of the pressure oscillations. The ratio of the integrated heat transfer within the cavity to the heat transfer from a flat plate with area equal to the area of the cavity opening was found to vary from 1.10 to 0.40, depending on Mach number and cavity resonance conditions.