Method for sound field separation by double plane vibration speed measurement and two dimensional space Fourier transform

Abstract

The invention provides a method for sound field separation by double plane vibration speed measurement and two dimensional space Fourier transform, which is characterized in that a measurement plane S1 and an auxiliary measurement plane S2 parallel therewith and Delta h away therefrom are disposed in the measurement sound field; normal direction particle vibration speed is measured on two planes; wave number domain transfer relationship between normal direction particle vibration speed on two measurement planes is established by the two dimensional space Fourier transform; sound pressure, normal direction particle vibration speed radiated by sound sources on both sides of the two measurement planes is separated according to the transferring relation. The method adopts two dimensional space Fourier transform as the sound field separation algorithm, making computation speed fast, and implementation simple; normal direction particle vibration speed on two measurement plane is used as the input for separation, so that the separated normal direction particle vibration speed has higher accuracy comparing with using sound pressure on two measurement planes as the input. The method can be widely applied for near-field acoustic holographic measurement under internal sound field or noise environment, material reflection coefficient measurement, scattering sound field separation.

Description

technical field [0001] The invention relates to a sound field separation method in the field of noise in the specialty of physics. Background technique [0002] In actual measurement, it is usually encountered that there are sound sources on both sides of the measurement surface, or there is reflection or scattering on one side of the measurement surface. In actual engineering, in order to more accurately study the sound radiation characteristics of the target sound source or the reflection characteristics of the reflective surface, it is necessary to separate the radiated sound from both sides of the measurement surface. The sound field separation technology based on double-sided sound pressure measurement and two-dimensional space Fourier transform method is an effective method proposed by G.V.Frisk et al. based on the near-field acoustic holography technology proposed by E.G.Williams et al. sound field separation technology. In the past two decades, many scholars at hom...

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Problems solved by technology

[0003] The two-dimensional spatial Fourier transform method is used as the sound field separation algorithm, which has the advantages of fast calculation speed and simple implementation; however, due to the limitation of the Fourier transform algorithm, the shape of the measurement surface can only be a regular shape such as a plane, cylinder or sphere, and the separation error Too big

In particular, the existing sound field separation technology based on double-sided sound pressure measurement and the two-dimensional space Fourier transform method uses the sound pressure on the two measurement surfaces as the input for separation. The separated sound pressure has high accuracy, but the separated The normal particle velocity accuracy is relatively low

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