A Formulation for Numerically Computing Sound at Moving Observers Based on Frequency-Domain Ffowcs Williams-Hawkings Equation

To circumvent the difficulties in computing sound at moving observers for the prompting Cooperative Autonomous Underwater Vehicles, we propose a frequency-domain formulation for computing sound with Ffowcs Williams-Hawkings equation. The proposed formulation avoids the expensive integration at each moment over the frequency domain when the acoustic pressure is computed at moving observers, because we novelly decompose the far-field asymptotics of the Green's function into time- and frequency-dependent components. The proposed formulation is applicable to computation of sound at moving observers with both rectilinear and non-rectilinear motions in subsonic flows. We validate the proposed formulation by computing sound generated from moving acoustic monopole and dipole in freestream flows. The oscillating and rectilinear motions of a far-field observer along various paths are specially considered. The results demonstrate that the proposed formulation provides reliable predictions for sound received by moving observers

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2008年,环境保护部和中国科学院联合启动了《中国生物多样性红色名录——高等植物卷》的编制工作。通过这项工作,我们依据IUCN濒危物种红色名录标准对中国野生高等植物的濒危状况进行了全面评估,编制了中国高等植物红色名录。2013年9月,该名录以环境保护部、中国科学院第54号公告形式发布,即《中国生物多样性红色名录—

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