Noise Identification in a Hot Transonic Jet Using Low-Dimensional Methods; Final technical rept. 1 Jan 2005-31 Dec 2007

摘要

The goal of this effort has been to identify the dominant source of the radiated aero-acoustic noise produced by high-speed, heated jets and develop control strategies to reduce it. To that end, two acoustically matched Mach 0.6 jets, at temperature ratio Tr=O.93 (cold) and Tr=1.7 (hot) are examined. The use of non-intrusive Particle Image Velocimetry (PIV) to sample the flow, allowed a true measure of the velocity field to be realized without fear of corrupting the radiated noise field intrinsic to each jet. The low- order modal dominance of each was determined using Proper Orthogonal Decomposition (POD), highlighting the low-dimensional nature of this highly turbulent flow field.