Abstract
This paper describes jet noise measurement recently conducted at the Japan Aerospace Exploration Agency (JAXA). Measurement techniques with regard to jet noise are of great importance for better understanding the noise generation mechanism and evaluating noise suppression characteristics of jet noise suppressors. As jet noise is influenced by the flow structure behind the nozzle, noise-related measurement should be done from various points of view. In attempting to satisfy these requirements, JAXA focused on three aspects of jet noise-related measurement: 1) the far-field sound properties, which the nozzle and subsequent jet provide; 2) the near-field sound sources formed primarily by the aerodynamic process; and 3) the flow profiles such as pressure and temperature distributions behind the nozzle or engine.
