Rotating Microphone Rake Measures Spinning Acoustic Modes

Rotating rake of pressure transducers developed for use in experimental studies of sources and propagation of noise generated by subsonic fan engines. Pressure transducers used as microphones to measure acoustic modes generated by, and spin with, fans. Versatility of control software used in rake-drive system enables measurements of acoustic modes on wide range of test-engine configurations. Rake-drive hardware easily adapted to different engines because not mechanically coupled to engine under test.