Acoustic test facility and the exhaust nozzle null diffusion

摘要

PROBLEM TO BE SOLVED: To provide an acoustic test facility which is improved so as to allow automatically controlling and generating a large power and high frequency sound which can not be covered by an acoustic converter, and a jet nozzle used for it. SOLUTION: The acoustic test facility comprises an echo chamber 1 where a diffuse sound field is formed and a test piece 2 is placed, an acoustic converter 4 for generating sound pressure spectrums of high frequency components in the echo chamber 1, an air pressure generator 5 for supplying the acoustic converter 4 with compressed air and an acoustic control apparatus 9 for controlling a compressed air flow emitted into the echo chamber 1 and the sound pressure spectrums of the high frequency components generated in the echo chamber 1, and is also provided with a high pressure air emitting apparatus 19 for branching the compressed air supplied from the air pressure generator 5 to the acoustic converter 4 at a branching path and emitting the compressed air into the echo chamber 1 as a jet flow and a regulator 20 intermediately provided on the blanching path of the compressed air to the high pressure air emitting apparatus 19 and controlling an opening angle based on a control signal from a computer 10 in the acoustic control apparatus 9.