Method for sound field separation by double plane vibration speed measurement and equivalent source method

Abstract

The invention provides a method for sound field separation by double plane vibration speed measurement and equivalent source method, which is characterized in that a measurement plane S1 and an auxiliary measurement plane S2 parallel therewith and Delta h therefrom are provided in the measured sound field; normal direction particle vibration speed on the two planes are measured; two imaginary source planes S1* and S2* are provided, and equivalent source are distributed on the imaginary source planes; transfer relationship between the equivalent source and normal direction particle vibration speed on two measurement planes are established; strength of each equivalent source on the imaginary source planes S1* and S2* are determined according to the transfer relationship; sound pressure and normal direction particle vibration speed radiated by sound sources on both sides of the two measurement planes are separated according to strength of equivalent source on two imaginary source plane. The invention adopts equivalent source method as the sound source separation algorithm, which has great computation stability, high computation accuracy, and simple implementation; normal direction vibration speed on two measurement planes are used as input for the separation, therefore vibration speed of the separated normal direction particle has high accuracy. The method is widely applicable 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. Existing separation methods include: (1) Sound field separation technology based on double-sided sound pressure measurement and two-dimensional spatial Fourier transform method. This method was proposed by G.V.Frisk et al. on the basis of the near-field acoustic holography technology proposed by E.G.Williams et al. and the double-sided measurement method p...

AI Technical Summary

Problems solved by technology

Based on double-sided sound pressure measurement and two-dimensional space Fourier transform method has its inherent defects: on the one hand, the shape of the measurement surface is limited, that is, it can only be a regular shape such as a plane, cylinder or sphere; on the other hand, it is limited by the Fourier transform algorithm The separation error is large, especially when the sound pressure difference from both sides of the measurement surface is large, the error is particularly obvious

Defects of this method: there are restrictions on the shape of the measurement surface, that is, it can only be a regular shape such as a plane, a cylinder or a sphere

Defects of this method: there are singular integrals, non-uniqueness of solutions, etc., and the calculation efficiency is low

This method uses the sound pressure on the two measuring surfaces as the input to separate, and the separation accuracy of the sound pressure is high, but the separation accuracy of the normal particle vibration velocity is relatively low

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