Effect of the ground surface and meteorological conditions on the active control of a monopole noise source

Ann Nakashima, Murray Hodgson

Abstract


Atmospheric refraction and soft ground have a significant effect on the performance of a single-channel active noise control (ANC) system. However, under such conditions the noise levels near the ground were significantly attenuated due to the upward refraction of sound waves. It would be more important to concentrate on attenuating the noise under temperature inversion and downwind conditions.

Keywords


Acoustic fields; Acoustic noise; Acoustic wave refraction; Aircraft propellers; Attenuation; Control systems; Earth atmosphere; Green's function; Thermal gradients; Wind effects; Green function parabolic equation method; Monopole noise source; Temperature inversion; Wind speed

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