A-24 マイクロジェットを用いた超音速ジェット騒音低減の実験的検討(空力VI,一般講演)

概要

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Jet noise reduction is a current key issue to realize environmentally-friendly, highly efficient supersonic jet engines in future. A series of experimental study was conducted concerning active control of supersonic jet noise with a microjet injection technique. The microjets were injected into a rectangular main jet with Mach number of up to 1.49. The nozzle lip of the main jet was equipped with 44 injection holes of the microjets, whose angles against the main jet were changed as 0, 60, and 90 degrees. From far-field sound pressure data, a significant reduction of the jet noise by several dB was found in the cases with 60 and 90 degrees of injection angles. Schlieren visualization was also made for the jet flow, and the microjet was observed to affect the shock structure and shear layer behavior of the supersonic jet.
2008-10-01