CN101403634A - Method for sound field separation by pressure velocity method - Google Patents

Abstract

The invention discloses a pressure speed method sound field separation method, a measured sound field is provided with a measuring surface S; a sound pressure sensor is adopted to measure the sound pressure on the measuring surface S, and a particle velocity sensor or a sound intensity probe is adopted to measure the particle speed on the measuring surface S; both sides of the measuring surface S are provided with the imaginary source surfaces S1 <*> and S2 <*> which are provided with the equivalent sources; the transfer relationship between the equivalent sources and the sound pressure and the particle speed on the measuring surface S is constructed; the separation of sound source radiation sound pressure and the particle speed of both sides on the measuring surface according to the transfer relationship is realized; the sound field separation is realized by measuring the speed relation of sound pressure and particle on each surface; and the equivalent source method is adopted as the sound field separation arithmetic, the calculation stability is good, the calculation precision is high, and the implement is simple. The method can be widely applicable to the near-field acoustic holography measurement in the environments of internal sound field or noisy sound, the sound intensity method sound source identification in the noisy environment, the material reflection coefficient measurement, and the separation of the scattering sound field.

Description

Method for sound field separation by pressure velocity method

Technical field:

The present invention relates to noise class field method for sound field separation in the Speciality of Physics, a kind of specifically method for sound field separation by pressure velocity method.

Background technology:

When actual measurement, can run into measurement face both sides usually all has sound source, or a side of the face of measurement exists reflection or scattering.And in the actual engineering, for the sound radiation characteristic of studying actual sound source more exactly or the reflection characteristic of reflecting surface, need and will separate from the radiation sound of the face of measurement both sides.G.Weinreich etc. propose to adopt two to lean on to such an extent that the method for very near measurement planar survey realizes separating of incident wave and radiated wave in 1980.G.V.Frisk has set up the two measurement face method for sound field separation based on space FFT method on the basis of the two-sided measuring method that near field acoustic holography technology that E.G.Williams etc. proposes and G.Weinreich etc. propose.This method is further used and is developed in following period of time subsequently.M.Tamura has set up in detail by two-sided measurement, and the sound field that adopts two-dimensional space FFT method to realize is again separated formula, and tries to achieve the reflection coefficient of reflecting interface by numerical simulation and Success in Experiment.Z.Hu and J.S.Bolton are also to adopting this method measurement plane wave reflection coefficient to carry out further checking.M.T.Cheng etc. have set up the Di Kaer coordinate and have separated formula with the two measurement face sound fields under the cylindrical coordinates, and are used to realize the separation of scattering sound field, have analyzed the susceptibility that this method is separated scattered field.F.Yu etc. successfully adopt this method to separate near field acoustic holography measuring process on the holographic facet noise from dorsad.Two measurement face method for sound field separation based on space FFT method have its intrinsic defective: restricted to the shape of measuring face on the one hand, and promptly can only be regular shapes such as plane, cylinder or sphere; Be subjected to the influence of fft algorithm on the other hand, the separation error is bigger, and especially when differing big from the face of measurement both sides acoustic pressure, its error is particularly evident.

F.Jacobsen etc. are on the basis of the method that J.Hald proposes, proposed based on the optimum method for sound field separation of the statistics of acoustic pressure and velocity survey, the p-u sound intensity probe of this method employing Microflow company is measured acoustic pressure and the particle vibration velocity on the sound field holographic facet simultaneously, adopts the associating solution formula of setting up to realize separating from the radiated sound field of holographic facet both sides again.The defective of this method: restricted to the shape of measuring face, promptly can only be regular shapes such as plane, cylinder or sphere.

C.Langrenne etc. propose a kind of two-sided method for sound field separation based on boundary element method.This method is at first measured the acoustic pressure on the parallel equidistant measurement face of two envelope sound sources; Adopt the Helmholtz integral method to separate incident and sound radiation pressure field again.The defective of this method: the processing such as nonuniqueness of have singular integral, separating, counting yield is low.

Summary of the invention:

Technical matters solved by the invention is to avoid above-mentioned existing in prior technology weak point, provides a kind of and realizes conveniently, is applicable to arbitrary shape measuring face, the method for sound field separation that the employing equivalent source method is realized, pressure-speed is measured that computational stability is good, computational accuracy is high.

The technical scheme that technical solution problem of the present invention is adopted is:

The inventive method is carried out as follows:

Acoustic pressure information on a, the measurement measurement face S

In the tested sound field that constitutes by sound source 1 and sound source 2, between sound source 1 and sound source 2, measurement face S is arranged; Be distributed with the measurement net point on measurement face respectively, the distance between the neighbor mesh points is less than half wavelength; The sound pressure amplitude at each net point place and phase information obtain the acoustic pressure on the measurement face on the measurement face of measurement; Described tested sound field is a steady sound field;

B, measuring setting virtual source face S between face S and the sound source 1 ₁ ^*, measuring setting virtual source face S between face S and the sound source 2 ₂ ^*, and on two virtual source faces, being distributed with equivalent source respectively, the number of equivalent source is not more than the corresponding torus network of measuring and counts; Described equivalent source is standard point source, face source or body source;

C, set up equivalent source and described measurement face S and go up transitive relation between acoustic pressure and the particle velocity

$p_1=p_1^{*}{W}_1$

$v_1=v_1^{*}{W}_1$

${\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">W</figure-callout>}}_2$

$v_2=v_2^{*}{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">W</figure-callout>}}_2,$ Wherein

p ₁Acoustic pressure, p for sound source 1 institute's radiation on the face of measurement S ₂For sound source 2 the acoustic pressure of measuring institute's radiation on the face S,

v ₁Particle velocity, v for sound source 1 institute's radiation on the face of measurement S ₂For sound source 2 the particle velocity of measuring radiation on the face S,

W ₁Be virtual source face S ₁ ^*Last equivalent source weight vector, W ₂Be virtual source face S ₂ ^*Last equivalent source weight vector,

p ₁ ^*Be virtual source face S ₁ ^*Transfer matrix between last equivalent source and the last acoustic pressure of the face of measurement S,

v ₁ ^*Be virtual source face S ₁ ^*Transfer matrix between last equivalent source and the last particle velocity of the face of measurement S,

p ₂ ^*Be virtual source face S ₂ ^*Transfer matrix between last equivalent source and the last acoustic pressure of the face of measurement S,

v ₂ ^*Be virtual source face S ₂ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the particle velocity;

D, set up the relation that measurement face S goes up acoustic pressure and particle velocity and both sides sound source radiation acoustic pressure and particle velocity

p＝p ₁+p ₂

V=v ₁+ v ₂, wherein

P is that acoustic pressure, the v that measurement face S upward measures is that measurement face S goes up the particle velocity of measuring;

E, separating and measuring face S go up acoustic pressure and the particle velocity by the both sides sound source radiation

The measurement face S that transitive relation of being set up according to step c and steps d are set up goes up the relation of acoustic pressure and particle velocity and both sides sound source radiation acoustic pressure and particle velocity, unites to find the solution the measurement face of acquisition S and go up by sound source 1 and sound source 2 acoustic pressure and the particle velocity of radiation respectively:

$p_1=p_1^{*}{(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)$

$v_1=v_1^{*}{(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)$

${\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{({\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}-G_1{v}_2^{*})}^{+}(p-G_{1}v)$

$v_2=v_2^{*}{({\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}-G_1{v}_2^{*})}^{+}(p-G_{1}v),$ Wherein

$G_1=p_1^{*}{\left(v_1^{*}\right)}^{+},$ ${\mathrm{<figure-callout\; id="2"\; label="G"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">G</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{\left(v_2^{*}\right)}^{+};$

The measurement of the acoustic pressure on each net point and particle velocity amplitude and phase information is to adopt single or multiple microphones and particle velocity sensors to scan, adopt sound intensity probe array snapshot or adopt single or multiple sound intensity probe arrays to scan acquisition on measurement face on measurement face respectively on measurement face.

Measurement face S is the arbitrary shape face.

The inventive method is acoustic pressure and the particle velocity of measuring on the measurement face S, adopts equivalent source method to realize separating by both sides sound source radiation acoustic pressure and particle velocity on the measurement face.

Theoretical model of the present invention:

The basic thought of equivalent source method is to adopt a series of equivalent source weighted stacking that are distributed in sound source inside to be similar to actual sound field, only needs this moment to determine that the source strength of these equivalent source is measurable whole sound field.In actual solution procedure, the source strength of equivalent source can pass through the boundary condition (acoustic pressure or normal direction vibration velocity) of the sound source of measurement and determine.For any measurement face in the sound field, also can be by the radiated sound field that distribution equivalent source on the virtual source face is similar to zone, side in face of this that deviates from the analysis domain at this face.

Referring to Fig. 1, the right side area field point r place acoustics amount of measuring face S can obtain by a series of equivalent source that are distributed in this left side of face virtual source face S* are approximate.If measure distributed respectively on face S and the virtual source face S* M measurement point and N equivalent source, the sound radiation pressure on the scene some r place of i equivalent source is p _i ^*(r) and particle rapidity be v _i ^*(r), then the actual emanations acoustic pressure at field point r place can be expressed as

$p\left(r\right)=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{w}_i{p}_i^{*}\left(r\right)---\left(1\right)$

$v\left(r\right)=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{w}_i{v}_i^{*}\left(r\right)---\left(2\right)$

W in the formula _iBe i the pairing source strength of equivalent source.The source strength of each equivalent source is determined that by the boundary condition of the face of measurement upward the acoustic pressure and the particle velocity of M measurement point can be expressed as can to measure face S by equation (1)

$p\left(r_j\right)=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{w}_i{p}_i^{*}\left(r_j\right),j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,M---\left(3\right)$

Formula (3) is write as matrix form

p＝p ^*W (4)

In the formula,

$p^{*}=\left[\begin{array}{cccc}{p}_1^{*}\left(r_1\right)& {\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}\left(r_1\right)& \&CenterDot;\&CenterDot;\&CenterDot;& p_N^{*}\left(r_1\right)\\ p_1^{*}\left(r_2\right)& {\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}\left(r_2\right)& \&CenterDot;\&CenterDot;\&CenterDot;& p_N^{*}\left(r_2\right)\\ \&CenterDot;& \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;& \&CenterDot;\\ p_1^{*}\left(r_M\right)& {\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}\left(r_M\right)& \&CenterDot;\&CenterDot;\&CenterDot;& p_N^{*}\left(r_M\right)\end{array}\right]---\left(5\right)$

W＝[w ₁?w ₂?…?w _N] (6)

In the formula, p is the acoustic pressure column vector at M measuring point place in the sound field; W is the shared weight coefficient column vector of a corresponding N equivalent source; p ^*Be the M * N rank transfer matrix between N equivalent source and M the measuring point place acoustic pressure.

In like manner, the particle velocity of last M the measurement point of measurement face S can be expressed as

v＝v ^*W (7)

In the formula, v is the particle velocity column vector at M measuring point place in the sound field; v ^*Be the M * N rank transfer matrix between N equivalent source and M the measuring point place acoustic pressure.

After trying to achieve the weight coefficient matrix W, just can calculate in the sound field arbitrarily any acoustic pressure and vibration velocity, realize the prediction of sound field by formula (1) and formula (2).

As from the foregoing, the radiated sound field of measurement face one side a series of equivalent source that can distribute by the opposite side at this measurement face are similar in the sound field.If all there is sound source the both sides of the face of measurement, then acoustic pressure on the measurement face and particle velocity are the combination of both sides sound source radiation acoustic pressure.

Referring to Fig. 2, the acoustic pressure of measuring on the face S is

p＝p ₁+p ₂ (8)

P in the formula ₁For sound source 1 is being measured face S ₁The acoustic pressure of last institute radiation, p ₂Acoustic pressure for sound source 2 institute's radiation on the face of measurement S.Particle velocity on the measurement face S is expressed as

v＝v ₁+v ₂ (9)

V in the formula ₁Be the acoustic pressure of sound source 1 institute's radiation on the face of measurement S, v ₂Acoustic pressure for sound source 2 institute's radiation on the face of measurement S.

Owing to be difficult to directly the acoustic pressure and the particle velocity of both sides sound source radiation on the measurement face be separated.Method of the present invention is to measure acoustic pressure and particle velocity on same simultaneously, and then realizes separating by equivalent source method.

As from the foregoing, measure face S and go up 1 sound radiation pressure p of sound source ₁With particle velocity v ₁Can be by measuring the virtual source face S that is provided with between face S and the sound source 1 ₁ ^*The a series of equivalent source of last distribution are similar to, and measure face S and go up 2 sound radiation pressure p of sound source ₂With particle velocity v ₂Can be by measuring the virtual source face S that is provided with between face S and the sound source 2 ₂ ^*The a series of equivalent source of last distribution are similar to.

$p_1=p_1^{*}{W}_1---\left(10\right)$

$v_1=v_1^{*}{W}_1---\left(11\right)$

${\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{W}_2---\left(12\right)$

${\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*}{W}_2---\left(13\right)$

In the formula, p ₁Be the acoustic pressure of sound source 1 institute's radiation on the face of measurement S, p ₂Be the acoustic pressure of sound source 2 institute's radiation on the face of measurement S, v ₁Be the particle velocity of sound source 1 institute's radiation on the face of measurement S, v ₂Be the particle velocity of sound source 2 radiation on the face of measurement S, W ₁Be virtual source face S ₁ ^*Last equivalent source weight vector, W ₂Be virtual source face S ₂ ^*Last equivalent source weight vector, p ₁ ^*Be virtual source face S ₁ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the acoustic pressure, v ₁ ^*Be virtual source face S ₁ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the particle velocity, p ₂ ^*Be virtual source face S ₂ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the acoustic pressure, v ₂ ^*Be virtual source face S ₂ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the particle velocity.

With formula (10), (11), (12) and (13) difference substitution formula (8) and (9), then can obtain following relation

$p=p_1^{*}{W}_1+{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{W}_2---\left(14\right)$

$v=v_1^{*}{W}_1+{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*}{W}_2---\left(15\right)$

Association type (14) and (15) can get

$W_1={(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)---\left(16\right)$

${\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">W</figure-callout>}}_2={({\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}-G_1{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*})}^{+}(p-G_{1}v)---\left(17\right)$

In the formula

$G_1=p_1^{*}{\left(v_1^{*}\right)}^{+}---\left(20\right)$

${\mathrm{<figure-callout\; id="2"\; label="G"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">G</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{\left({\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*}\right)}^{+}---\left(21\right)$

Subscript "+" representing matrix generalized inverse in the formula.

Formula (16) and (17) difference substitution formula (10), (11), (12) and (13) can be obtained to measure acoustic pressure and the particle velocity that face S goes up sound source 1 and 2 radiation of sound source respectively.

By said method, realized separating of acoustic pressure and particle velocity on the measurement face, can obtain sound radiation pressure and particle velocity from the face of measurement both sides sound source.

Compared with the prior art, beneficial effect of the present invention:

1, measurement face of the present invention can be the arbitrary shape measuring face, solved the defective that classic method can only be applicable to regular shapes such as plane, cylinder or sphere.

2, the present invention adopts equivalent source method to be used as the sound field separation algorithm, compares with classic method, and the inventive method has that computational stability is good, the computational accuracy advantages of higher.

3, the inventive method is measured only needs to carry out on a measurement face.

4, the inventive method is implemented simply, can be widely used in that near field acoustic holography under internal acoustic field or the noise circumstance is measured, the sound intensity technique identification of sound source under the noise circumstance, the measurement of material reflection coefficient, the separation of scattering sound field etc.

Description of drawings:

Fig. 1 is a plane sound source equivalent source location map;

Fig. 2 is that pressure-speed method sound field is separated synoptic diagram;

Fig. 3 (a) measures the sound pressure amplitude distribution that face S goes up actual measurement;

Fig. 3 (b) measures face S and goes up the theoretical amplitude distribution of sound source 1 sound radiation pressure;

The sound source 1 sound radiation pressure amplitude distribution that Fig. 3 (c) adopts the inventive method to separate;

Fig. 3 (d) measures the sound pressure phase distribution that face S goes up actual measurement;

Fig. 3 (e) measures face S and goes up the distribution of sound source 1 sound radiation pressure notional phase;

The sound source 1 sound radiation pressure PHASE DISTRIBUTION that Fig. 3 (f) adopts the inventive method to separate;

Fig. 4 (a) measures the particle velocity amplitude distribution that face S goes up actual measurement;

Fig. 4 (b) measures face S and goes up the theoretical amplitude distribution of sound source 1 radiation quality spot speed;

The sound source 1 radiation quality spot speed amplitude distribution that Fig. 4 (c) adopts the inventive method to separate;

Fig. 4 (d) measures the particle velocity PHASE DISTRIBUTION that face S goes up actual measurement;

Fig. 4 (e) measures face S and goes up the distribution of sound source 1 radiation quality spot speed notional phase;

The sound source 1 radiation quality spot speed PHASE DISTRIBUTION that Fig. 4 (f) adopts the inventive method to separate;

Below pass through embodiment, and in conjunction with the accompanying drawings the present invention is further described.

Embodiment:

Referring to Fig. 2, in the present embodiment, measure the face both sides and be distributed with sound source, wherein sound source 1 is main sound source, sound source 2 is noise source or reflection, scattering source, in the tested sound field that is made of sound source 1 and sound source 2, between sound source 1 and sound source 2 measurement face S is arranged; Be distributed with the measurement net point on measurement face respectively, the distance between the neighbor mesh points is less than half wavelength.

Concrete implementation step is:

A, adopt single or multiple microphones and particle velocity sensors on measurement face, to scan, adopt sound intensity probe array snapshot or adopt single or multiple sound intensity probe arrays on measurement face, scan acoustic pressure and particle velocity information on the acquisition measurement face S on measurement face respectively;

B, measuring setting virtual source face S between face S and the sound source 1 ₁ ^*, measuring setting virtual source face S between face S and the sound source 2 ₂ ^*, and on two virtual source faces, being distributed with equivalent source respectively, the number of equivalent source is not more than the corresponding torus network of measuring and counts; Described equivalent source is standard point source, face source or body source;

C, set up the transitive relation between equivalent source and the described two measurement faces

$p_1=p_1^{*}{W}_1$

$v_1=v_1^{*}{W}_1$

${\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">W</figure-callout>}}_2$

${\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*}{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">W</figure-callout>}}_2,$ Wherein

p ₁Acoustic pressure, p for sound source 1 institute's radiation on the face of measurement S ₂For sound source 2 the acoustic pressure of measuring institute's radiation on the face S,

v ₁Particle velocity, v for sound source 1 institute's radiation on the face of measurement S ₂For sound source 2 the particle velocity of measuring radiation on the face S,

W ₁Be virtual source face S ₁ ^*Last equivalent source weight vector, W ₂Be virtual source face S ₂ ^*Last equivalent source weight vector,

p ₁ ^*Be virtual source face S ₁ ^*Transfer matrix between last equivalent source and the last acoustic pressure of the face of measurement S,

v ₁ ^*Be virtual source face S ₁ ^*Transfer matrix between last equivalent source and the last particle velocity of the face of measurement S,

p ₂ ^*Be virtual source face S ₂ ^*Transfer matrix between last equivalent source and the last acoustic pressure of the face of measurement S,

v ₂ ^*Be virtual source face S ₂ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the particle velocity;

D, set up the relation that measurement face S goes up acoustic pressure and particle velocity and both sides sound source radiation acoustic pressure and particle velocity

p＝p ₁+p ₂

V=v ₁+ v ₂, wherein

P is that acoustic pressure, the v that measurement face S upward measures is that measurement face S goes up the particle velocity of measuring;

E, separating and measuring face S go up acoustic pressure and the particle velocity by the both sides sound source radiation

The measurement face S that transitive relation of being set up according to step c and steps d are set up goes up the relation of acoustic pressure and particle velocity and both sides sound source radiation acoustic pressure and particle velocity, unites to find the solution the measurement face of acquisition S and go up by sound source 1 and sound source 2 acoustic pressure and the particle velocity of radiation respectively:

$p_1=p_1^{*}{(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)$

$v_1=v_1^{*}{(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)$

${\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{({\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}-G_1{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*})}^{+}(p-G_{1}v)$

${\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*}{({\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}-G_1{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*})}^{+}(p-G_{1}v),$ Wherein

$G_1=p_1^{*}{\left(v_1^{*}\right)}^{+},$ ${\mathrm{<figure-callout\; id="2"\; label="G"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">G</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">p</figure-callout>}}_2^{*}{\left({\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="A20081019475400151.png"\; state="\{\{state\}\}">v</figure-callout>}}_2^{*}\right)}^{+};$

The check of method:

Respectively arrange a pulsation ball in the face of measurement both sides, adopt method for sound field separation enforcement sound field of the present invention to separate respectively, and compare with its analytic solution.

For single radius is the pulsation ball of a, and the analytic solution of its on the scene some r place acoustic pressure are

$p(r,\mathrm{\&theta;})=-v\&CenterDot;\frac{i2\mathrm{\&pi;}{\mathrm{f\&rho;a}}^2}{r(1-\mathrm{ika})}\&CenterDot;\exp \left[\mathrm{ik}(r-a)\right],---\left(22\right)$

In the formula, even radial velocity v=1m/s, atmospheric density is ρ=1.2kg/m ³, the sound source vibration frequency is 1kHz.

Two measure the position relation of face referring to Fig. 2.Measurement face is the plane of 1m * 1m, and 21 * 21 measurement points equably distribute on the measurement face.Sound source 1 is for being positioned at the pulsation ball at (0.3,0,0) m place, and sound source 2 is for being positioned at the pulsation ball at (0.3 ,-0.25,0.2) m place.Distance 1 and 2 between measurement face and the virtual source face is 0.1m.Sound source 1 is main sound source herein, and sound source 2 is a noise source, last sound source 1 sound radiation pressure of the face of measurement S and particle velocity need be separated.

Referring to Fig. 3 (wherein, Fig. 3 (a) and Fig. 3 (d) go up the sound pressure amplitude and the PHASE DISTRIBUTION of actual measurement for measurement face S, the sound pressure amplitude and the PHASE DISTRIBUTION of Fig. 3 (b) and Fig. 3 (e) radiation on the face of measurement S that is sound source 1, Fig. 3 (c) and Fig. 3 (f) are the sound pressure amplitude and the PHASE DISTRIBUTION of sound source 1 radiation on measurement face S of adopting the inventive method and separating; Fig. 4 (a) and Fig. 4 (d) go up the particle velocity amplitude and the PHASE DISTRIBUTION of actual measurement for measurement face S, Fig. 4 (b) and Fig. 4 (e) are the particle velocity amplitude and the PHASE DISTRIBUTION of sound source 1 radiation on the face of measurement S, Fig. 4 (c) and Fig. 4 (f) are the particle velocity amplitude and the PHASE DISTRIBUTION of sound source 1 radiation on the face of measurement S of adopting the inventive method and separating), after adopting the inventive method to implement to separate, can accurately obtain sound source 1 and measure radiation information on the face S, it is very identical to isolate the amplitude of acoustic pressure and particle velocity and PHASE DISTRIBUTION and its theoretical value.

For the separation accuracy of quantitative description the inventive method more, definition separates percentage error and is

$\mathrm{\&eta;}=\sqrt{\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{\left(\right|p_i|-|{\stackrel{\&OverBar;}{p}}_i\left|\right)}^2}/\sqrt{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left|{\stackrel{\&OverBar;}{p}}_i\right|}^2}\&times;100(\%),---\left(23\right)$

In the formula, N is the surperficial node sum of all sound sources, p _iAnd p _iBe respectively corresponding i measurement point that separate with acoustic pressure or particle velocity theory.Calculated and can be got by formula (23), acoustic pressure is separated percentage error and is respectively 0.43% and 0.35% with particle velocity, obviously adopt the inventive method can obtain point-device result.

Claims (5)

1, method for sound field separation by pressure velocity method is characterized in that being carrying out as follows:

Acoustic pressure information on a, the measurement measurement face S

In the tested sound field that constitutes by sound source 1 and sound source 2, between sound source 1 and sound source 2, measurement face S is arranged; Be distributed with the measurement net point on measurement face respectively, the distance between the neighbor mesh points is less than half wavelength; The sound pressure amplitude at each net point place and phase information obtain the acoustic pressure on the measurement face on the measurement face of measurement; Described tested sound field is a steady sound field;

B, measuring setting virtual source face S between face S and the sound source 1 ₁ ^*, measuring setting virtual source face S between face S and the sound source 2 ₂ ^*, on two virtual source faces, being distributed with equivalent source respectively, the number of equivalent source is not more than the corresponding torus network of measuring and counts; Described equivalent source is standard point source, face source or body source;

C, set up equivalent source and described measurement face S and go up transitive relation between acoustic pressure and the particle velocity

$p_1=p_1^{*}{W}_1$

$v_1=v_1^{*}{W}_1$

$p_2=p_2^{*}{W}_2$

$v_2=v_2^{*}{W}_2,$ Wherein

p ₁Acoustic pressure, p for sound source 1 institute's radiation on the face of measurement S ₂For sound source 2 the acoustic pressure of measuring institute's radiation on the face S,

v ₁Particle velocity, v for sound source 1 institute's radiation on the face of measurement S ₂For sound source 2 the particle velocity of measuring radiation on the face S,

W ₁Be virtual source face S ₁ ^*Last equivalent source weight vector, W ₂Be virtual source face S ₂ ^*Last equivalent source weight vector,

p ₁ ^*Be virtual source face S ₁ ^*Transfer matrix between last equivalent source and the last acoustic pressure of the face of measurement S,

v ₁ ^*Be virtual source face S ₁ ^*Transfer matrix between last equivalent source and the last particle velocity of the face of measurement S,

p ₂ ^*Be virtual source face S ₂ ^*Transfer matrix between last equivalent source and the last acoustic pressure of the face of measurement S,

v ₂ ^*Be virtual source face S ₂ ^*Last equivalent source and the face of measurement S go up the transfer matrix between the particle velocity;

D, set up the relation that measurement face S goes up acoustic pressure and particle velocity and both sides sound source radiation acoustic pressure and particle velocity

p＝p ₁+p ₂

V=v ₁+ v ₂, wherein

P is that acoustic pressure, the v that measurement face S upward measures is that measurement face S goes up the particle velocity of measuring;

E, separating and measuring face S go up acoustic pressure and the particle velocity by the both sides sound source radiation

The measurement face S that transitive relation of being set up according to step c and steps d are set up goes up the relation of acoustic pressure and particle velocity and both sides sound source radiation acoustic pressure and particle velocity, unites to find the solution the measurement face of acquisition S and go up by sound source 1 and sound source 2 acoustic pressure and the particle velocity of radiation respectively:

$p_1=p_1^{*}{(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)$

$v_1=v_1^{*}{(p_1^{*}-G_2{v}_1^{*})}^{+}(p-G_{2}v)$

$p_2=p_2^{*}{(p_2^{*}-G_1{v}_2^{*})}^{+}(p-G_{1}v)$

$v_2=v_2^{*}{(p_2^{*}-G_1{v}_2^{*})}^{+}(p-G_{1}v),$ Wherein

$G_1=p_1^{*}{\left(v_1^{*}\right)}^{+},$ $G_2=p_2^{*}{\left(v_2^{*}\right)}^{+}.$

2, method for sound field separation according to claim 1, the measurement that it is characterized in that acoustic pressure on described each net point and particle velocity amplitude and phase information are to adopt single or multiple microphones and particle velocity sensors to scan, adopt sound intensity probe array snapshot or adopt single or multiple sound intensity probes to scan acquisition on measurement face on measurement face respectively on measurement face.

3, method for sound field separation according to claim 1 is characterized in that described measurement face S is the arbitrary shape face.

4, method for sound field separation according to claim 1 is characterized in that it is to adopt acoustic pressure on the measurement face S and particle velocity as input quantity that sound field is separated.

5, method for sound field separation according to claim 1 is characterized in that adopting equivalent source method to realize the sound field separation in the face of measurement S both sides distribution equivalent source.

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