Precise sound source model for aircraft noise prediction based on noise source distribution determined by phased array beamforming

摘要

In order to predict noise around an airport more precisely, we have been investigating a sound source model, in which noise sources of an aircraft such as engine noise and airframe noise are individually modeled as a point source. To determine the detail sound source properties including a position and frequency characteristics through a filed measurement, phased-array microphone system which can accurately identify the location of noise sources around aircraft in flight was used. Noise sources such as engine exhaust noise and aerodynamic noise generated at flaps or landing gears are modeled as a point source with directivity, then sound power levels and directivities of each noise source generated by an aircraft in flight in each 1/3 octave band are determined from the noise source distribution obtained by the phased-array microphone system. In order to validate the proposed sound source model, aircraft noise prediction was conducted using the sound source model, and the results are compared with measurements in terms of the time history of the sound pressure level.