A Free Field Restoration Method for Unsteady Plane Sound Source

Abstract

The invention discloses a free-field restoration method of an unsteady plane sound source. The time-domain sound pressure signals on two measurement planes are subjected to two-dimensional spatial Fourier transform to obtain the time-domain sound pressure at each wave number on the corresponding plane. Wavenumber spectrum; using the sound pressure time-domain wavenumber spectrum on two measurement planes and the known time-domain impulse response function between the sound pressure and the sound pressure, the unsteady outward sound field and the inward sound field are separated; the target The surface reflection coefficient of the sound source is used as the boundary condition, and the relationship between the unsteady inward sound field and the scattered sound field is established, and the unsteady scattered sound field is calculated; the unsteady scattered sound field is removed from the separated unsteady outward sound field, The time-domain sound pressure signal radiated on the measurement plane under the free-field condition of the target sound source is restored. The invention realizes the elimination of unsteady scattered sound in the time domain, restores the time-domain sound pressure radiated on the measurement plane under the free-field condition of the target sound source, and accurately analyzes the time-varying radiation of the target sound source in the actual sound field environment Characteristics and vibration characteristics provide pre-processing means.

Description

technical field [0001] The invention relates to the field of noise in physics specialty, in particular to a free-field restoration method of an unsteady plane sound source. Background technique [0002] The actual sound field environment is a non-free field, which includes not only the radiated sound of the target sound source, but also the interference sound from the other side of the measurement surface and the scattered sound generated by the interference sound on the surface of the target sound source. In addition to the sound field produced by the interfering sound that can affect the sound field radiated by the target sound source, the scattered sound can also affect the accurate measurement of the radiated sound field of the target sound source. eliminated from the results. [0003] So far, scholars at home and abroad have proposed a variety of free-field restoration methods: Hu et al. derived a complete calculation formula for planar near-field acoustic holography b...

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Problems solved by technology

[0005] However, these time-domain separation methods can only remove the unsteady sound field produced by the interfering sound source on the other side of the measurement plane, and cannot eliminate the unsteady scattering sound field produced by the interfering sound on the surface of the target sound source

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