Evaluation of Lateral Attenuation for Aircraft Takeoff-roll Noise by Multi-point Measurement

摘要

It is indispensable to consider lateral attenuation for aircraft noise prediction around airport. In 2000's, we proposed a calculation method to predict lateral attenuation under various meteorological conditions by modifying the SAE AIR 1751 (" 1751M"). Afterwards, a lot of new types of aircraft or engines have been launched, and comparing results of noise prediction with measurements have suggested that "1751M" gives a bit underestimation of the values of lateral attenuation. Thus, we have started the study to check the validity of lateral attenuation equations for new types of aircraft. At first, the examination on the validity of lateral attenuation equations using long-term noise monitoring data at Narita airport have been carried out. Next, we planned a multi-point and short-term measurement to complement with long-term measurement for the detailed investigation. The multi-point noise measurement was carried out continuously 7 days in different seasons at Narita airport. In the measurements, aircraft noise was observed at different lateral distances of 190 m - 1460 m. 1/3 octave band analysis results of every moment was recorded at each point. This paper introduces parts of results of over-ground lateral attenuation.