Toward Airframe Noise Reduction for Passenger Aircraft

Airframe noise is one of the main noise sources of the latest passenger aircraft during the approach phase. To demonstrate noise reduction technology based on unsteady Computational Fluid Dynamics (CFD) and wind tunnel tests, JAXA conducted flight tests using the JAXA Experimental Aircraft "Hisho" in 2016 and 2017 in cooperation with industries in Japan. The noise data obtained from flyover noise source measurements successfully showed consistent characteristics with the noise reduction designs for the flaps and the main landing gear. The noise measurement data from the flight test 2017 were used to validate the wind tunnel tests and CFD used in the design phase. Subsequently, the research activities proceeded towards the research and development targeting regional jet aircraft, aiming for practical application in passenger aircraft. This paper overviews these research activities toward developing airframe noise reduction technology for passenger aircraft.