CN102997988A - Pool testing method of low-frequency acoustic directivity of large submerged buoy vector hydrophone - Google Patents

Abstract

The invention provides a pool testing method of low-frequency acoustic directivity of a large submerged buoy vector hydrophone. The pool testing method comprises the steps of (1) placing a submerged buoy system to the center of a pool, placing a low-frequency/very-low-frequency acoustic source to a position which enables the vector hydrophone in the submerged buoy system to be positioned in an acoustic source near field and the center of the vector hydrophone and the acoustic source to be positioned at the same placing depth, wherein the sound filed at the position of the vector hydrophone expands in a spherical wave mode; (2) determining the range of a rotary angle of the submerged buoy system according to the dimension of the submerged buoy system and equivalent conditions of testing results of the spherical wave and testing results of a plane wave; and (3) enabling the whole submerged buoy system to rotate at a low speed, recording signals when emission frequency of a sound pressure channel of the vector hydrophone is f0 in real time, and performing post-processing to obtain low-frequency/very-low-frequency acoustic directivity of the submerged buoy vector hydrophone. By means of the pool testing method, the testing of the acoustic directivity of the complicated vector hydrophone system can be achieved in a high precision mode in the pool which can be controlled easily, and accordingly, the requirements of further research are met.

Description

The pond method of testing of large-scale subsurface buoy vector hydrophone frequency acoustic directive property

Technical field

What the present invention relates to is a kind of underwater sound method of testing, is chiefly directed to the method for under the condition of pond the vector hydrophone system acoustics directive property that works in large-scale subsurface buoy being tested.

Background technology

Mostly the test of existing vector hydrophone acoustics directive property is test that whether vector hydrophone self dipole-type directive property is met the demands, and testing location is different and be chosen in pond, standing wave tube and outfield according to vector hydrophone frequency of operation, precision and purpose.Then rare open introduction of test for the vector hydrophone acoustics directive property that works in complication system (such as large-scale subsurface buoy, buoy etc.).The present invention then discloses a kind of method of under the condition of pond the vector hydrophone total system low frequency that works in large-scale subsurface buoy and very low frequency (VLF) acoustics directive property being tested.

Vector hydrophone system acoustics directive property has reflected the roomage response situation of this entire system to same incident plane wave, needs system to rotate a circle to obtain in the plane wave incident field during measurement.In low-frequency range especially very low frequency (VLF) section, be difficult in limited pond, obtain the plane wave free field, and isolated pool wall reflected signal is to the interference of directive property test, so that the vector hydrophone system uses plane wave free field method to carry out low frequency and the test of very low frequency (VLF) acoustics directive property is very difficult; Standing wave tube then is only applicable to the test of the vector hydrophone acoustics directive property of piezoelectric type and alliteration pressure type, can not satisfy equally the needs of large-scale submerged buoy system test; Although field testing can satisfy test to the requirement of plane wave free field, but test process is wayward, the testing expense cost prohibitive, and rearmounted data are processed compensation and are required too highly, also can not satisfy in the actual scientific research engineering application process requirement to large-scale subsurface buoy vector hydrophone acoustics directive property.

Document " the experiment pond of 20 ~ 2000Hz vector hydrophone directivity pattern is measured " (acoustic technique, 2009.28 (2): 131-132) provided the test findings of in the pond vector hydrophone self dipole-type directive property being tested.

Document " acoustic pressure, vibration velocity united information are processed " (Harbin Engineering University's PhD dissertation, 2000) provided the lake examination to the method for testing of vector hydrophone acoustic pressure and vector passage self dipole acoustics directive property: emission Single Frequency C W pulse, per 2 ° of measurements are once in 360 ° of scopes during measurement.From test result, the not enough 20dB of vector passage zero point depth.

The common feature of above-mentioned two parts of documents is only whether vector hydrophone self dipole-type directive property to be met the demands to test, and its method of testing also is not easy to the test of complicated vector hydrophone system acoustics directive property.And in the practical application of vector hydrophone, the auxiliary acoustics facilities such as indispensable needs configuration kuppe, baffle realize that recording of targets of interest information data obtain, and at this moment vector hydrophone and allocation of facility integral body thereof have consisted of a system.If the auxiliary equipment design is improper, installation is uncomfortable, just might affect the dipole directive property of system's vector hydrophone self.Therefore, to whole vector hydrophone system but not separately the acoustical behavior of vector hydrophone is tested and is seemed particularly important.

Summary of the invention

The object of the present invention is to provide a kind of control operation easy, the pond method of testing of the large-scale subsurface buoy vector hydrophone frequency acoustic directive property that measuring accuracy is high.

The object of the present invention is achieved like this:

(1) submerged buoy system is laid on the center, pond, low frequency/very low frequency (VLF) sound source is laid on the vector hydrophone that makes in the submerged buoy system is in sound source near field and vector hydrophone center and sound source and is in the same degree of depth that lays, namely vector hydrophone position sound field is spherical wave expanding change rule;

(2) according to the size of large-scale submerged buoy system, but and the equivalence condition of spherical wave test result and plane wave test result, determine the rotation angle range of submerged buoy system;

(3) rotate whole submerged buoy system with the slow-speed of revolution, real time record vector hydrophone sound pressure channel, the signal when transmission frequency is f0 obtain subsurface buoy vector hydrophone low frequency/very low frequency (VLF) acoustics directive property through the postposition processing.

The present invention can also comprise:

1, the submerged buoy system rotation is to rotate centered by the vector hydrophone center.

2, the selection of speed 1deg/s of described slow-speed of revolution rotation.

3, the described rearmounted method of processing comprises: the acoustic pressure p the when anglec of rotation is θ (t) and vibration velocity signal v _x(t) and v _y(t) after Fast Fourier Transform (FFT) FFT processing or zoomFFT processing, obtain corresponding amplitude Estimation:

A _p(f)＝FFT[p(t)]

$A_{v_x}\left(f\right)=\mathrm{FFT}\left[v_x\left(t\right)\right]$

Continue the rotation submerged buoy system and obtain [θ ₁, θ ₂] vector hydrophone in the angular range receives signal amplitude A accordingly _p(f, θ), $A_{v_x}(f,\mathrm{\θ})$ With $A_{v_y}(f,\mathrm{\θ});$

Polar form shows A _p(f, θ),

With

Namely realize the test of submerged buoy system vector hydrophone directive property.

In order to remedy the deficiency in the background technology, the present invention proposes a kind of under the condition of pond, but according to sound source in the pond closely the sound field equivalence condition that is spherical wave expanding change rule and spherical wave test result and plane wave test result consider, large-scale subsurface buoy vector hydrophone low frequency and very low frequency (VLF) acoustics directive property are carried out method of testing.Vector hydrophone is in the sound source near field when guaranteeing test, and its position sound field is spherical wave expanding change rule.By choose reasonable subsurface buoy rotation angle range, guarantee that the spherical wave test result can equivalence be the plane wave test result.

The invention has the advantages that and to be easy to like this under the condition of control operation in the pond, realize the test of complicated vector hydrophone system acoustics directive property with degree of precision, thereby satisfy further research needs.

Description of drawings

Fig. 1 is large-scale subsurface buoy vector hydrophone frequency acoustic directive property pond test configurations synoptic diagram.

Fig. 2 is large-scale subsurface buoy vector hydrophone frequency acoustic directive property pond test anglec of rotation synoptic diagram.

Acoustics directive property test synoptic diagram when Fig. 3 is plane wave incident.

Acoustics directive property test synoptic diagram when Fig. 4 is spherical wave incident.

Fig. 5 is the amplitude relation of scattering wave and incident wave under the plane wave incident condition.

Fig. 6 is directive property test result under the plane wave incident condition.

Fig. 7 is the amplitude relation of scattering wave and incident wave under the spherical wave incident condition.

Fig. 8 is directive property test result under the spherical wave incident condition.

Fig. 9 is the rearmounted disposal route that vector hydrophone receives signal.

Embodiment

For a more detailed description to the present invention for example below in conjunction with accompanying drawing.

Among the present invention, Fig. 1 has provided large-scale subsurface buoy vector hydrophone frequency acoustic directive property pond test configurations synoptic diagram.Requirements vector nautical receiving set 3 is in the sound source near field when laying configuration, and has guaranteed that vector hydrophone center and sound source 4 are in the same degree of depth that lays; Fig. 2 has provided large-scale subsurface buoy vector hydrophone frequency acoustic directive property pond test anglec of rotation synoptic diagram, has guaranteed that like this vector hydrophone position sound field is spherical wave expanding change rule, to make things convenient for the equivalence of spherical wave test result as the plane wave test result.

The first step, submerged buoy system 2 are laid in the pond 1 heart (L/2, H/2) low frequency/very low frequency (VLF) sound source 4 to lay the degree of depth are H/2, and both are at a distance of r ₀(specifically seeing Fig. 1); And vector hydrophone 3 is in the sound source near field, and vector hydrophone position sound field is spherical wave expanding change rule.

Second step according to submerged buoy system directive property theoretical study results, is selected subsurface buoy rotation angle range [θ ₁, θ ₂] (specifically seeing Fig. 2), to make things convenient for the equivalence of spherical wave test result as the plane wave test result.

Here the subsurface buoy (absolute hard ball and vector hydrophone combine) with a simple form illustrates equivalent theory:

As shown in Figure 3,11 expression vector hydrophone main shaft initial positions among Fig. 3.Synoptic diagram when this figure has provided the test of plane wave incident directive property.At this moment incident wave satisfies:

p _in＝e ^-jkrcosθ (1)

$v_{\mathrm{rin}}=\frac{\cos \mathrm{\θ}}{\mathrm{\ρc}}{e}^{-\mathrm{jkr}\cos \mathrm{\θ}}---\left(2\right)$

$v_{\mathrm{\θin}}=-\frac{\sin \mathrm{\θ}}{\mathrm{\ρc}}{e}^{-\mathrm{jkr}\cos \mathrm{\θ}}---\left(3\right)$

Scattering wave satisfies:

$p_s=-\underset{m=0}{\overset{\∞}{\mathrm{\Σ}}}{(-j)}^m(2m+1)\frac{{\mathrm{mj}}_{m-1}\left(\mathrm{ka}\right)-(m+1)j_{m+1}\left(\mathrm{ka}\right)}{{\mathrm{mh}}_{m-1}^{\left(2\right)}\left(\mathrm{ka}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{ka}\right)}{h}_m^{\left(2\right)}\left(\mathrm{kr}\right)P_m\left(\cos \mathrm{\θ}\right)---\left(4\right)$

$v_{\mathrm{rs}}=\frac{1}{\mathrm{j\ρ}\mathrm{\ω}}\underset{m=0}{\overset{\∞}{\mathrm{\Σ}}}{(-j)}^m\frac{{\mathrm{mj}}_{m-1}\left(\mathrm{ka}\right)-(m+1)j_{m+1}\left(\mathrm{ka}\right)}{{\mathrm{mh}}_{m-1}^{\left(2\right)}\left(\mathrm{ka}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{ka}\right)}[{\mathrm{mh}}_{m-1}^{\left(2\right)}\left(\mathrm{kr}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{kr}\right)]P_m\left(\cos \mathrm{\θ}\right)k---\left(5\right)$

$v_{\mathrm{\θs}}=-\frac{1}{\mathrm{j\ρ\ωr}}\underset{m=0}{\overset{\∞}{\mathrm{\Σ}}}{(-j)}^m(2m+1)\frac{{\mathrm{mj}}_{m-1}\left(\mathrm{ka}\right)-(m+1)j_{m+1}\left(\mathrm{ka}\right)}{{\mathrm{mh}}_{m-1}^{\left(2\right)}\left(\mathrm{ka}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{ka}\right)}{h}_m^{\left(2\right)}\left(\mathrm{kr}\right)\mathrm{sign}\left(\sin \mathrm{\θ}\right)P_m^{\left(1\right)}\left(\cos \mathrm{\θ}\right)---\left(6\right)$

Formula (4) ~ (6)

In, P _mBe Legendre polynomial, j _mBe spheric Bessel function,

Be Equations of The Second Kind ball Hankel function.Can obtain plane wave incident directive property when test by formula (1) ~ (6), vector hydrophone receives signal and is followed successively by in the subsurface buoy:

p＝p _in+p _s (7)

v _r＝v _rin+v _rs (8)

v _θ＝v _θin+v _θs (9)

Synoptic diagram when as shown in Figure 4, this figure has provided the test of spherical wave incident directive property.At this moment incident wave satisfies:

$p_{\mathrm{in}}=\frac{e^{\mathrm{kD}}}{D}---\left(10\right)$

In the formula, $D=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00002418010600011.png,HDA00002418010600022.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="HDA00002418010600031.png"\; state="\{\{state\}\}">r</figure-callout>}}_0^2+2{\mathrm{<figure-callout\; id="0"\; label="rr"\; filenames="HDA00002418010600031.png"\; state="\{\{state\}\}">rr</figure-callout>}}_0\cos {\mathrm{\&theta;}}_s},$ ${\mathrm{\&theta;}}_s=\mathrm{\&theta;}+a\sin \frac{r\sin \mathrm{\&theta;}}{{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="HDA00002418010600031.png"\; state="\{\{state\}\}">r</figure-callout>}}_0}.$

$v_{\mathrm{rin}}=\frac{1}{\mathrm{j\&rho;\&omega;}}\frac{\mathrm{jkD}-1}{D}\frac{r+{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="HDA00002418010600031.png"\; state="\{\{state\}\}">r</figure-callout>}}_0\cos {\mathrm{\&theta;}}_s}{D}\frac{e^{\mathrm{kD}}}{D}---\left(11\right)$

$v_{{\mathrm{\&theta;}}_s\mathrm{in}}=\frac{1}{\mathrm{j\&rho;\&omega;}}\frac{\mathrm{jkD}-1}{\mathrm{<figure-callout\; id="0"\; label="D\; r"\; filenames="HDA00002418010600031.png"\; state="\{\{state\}\}">D</figure-callout>}}\frac{r_{}}{}\frac{{}_0\cos {\mathrm{\&theta;}}_s}{D}\frac{e^{\mathrm{kD}}}{D}---\left(12\right)$

Scattering wave satisfies:

$p_s=\mathrm{jk}\underset{m=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{(-1)}^{m+1}(2m+1)\frac{{\mathrm{mj}}_{m-1}\left(\mathrm{ka}\right)-(m+1)j_{m+1}\left(\mathrm{ka}\right)}{{\mathrm{mh}}_{m-1}^{\left(2\right)}\left(\mathrm{ka}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{ka}\right)}{h}_m^{\left(1\right)}\left(k{r}_0\right)h_m^{\left(1\right)}\left(\mathrm{kr}\right)P_m\left(\cos {\mathrm{\&theta;}}_s\right)---\left(13\right)$

$v_{\mathrm{rs}}=\frac{k}{\mathrm{\&rho;}\mathrm{\&omega;}}\underset{m=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{(-1)}^{m+1}\frac{{\mathrm{mj}}_{m-1}\left(\mathrm{ka}\right)-(m+1)j_{m+1}\left(\mathrm{ka}\right)}{{\mathrm{mh}}_{m-1}^{\left(2\right)}\left(\mathrm{ka}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{ka}\right)}{h}_m^{\left(1\right)}\left({\mathrm{kr}}_0\right)[{\mathrm{mh}}_{m-1}^{\left(1\right)}\left(\mathrm{kr}\right)-(m+1)h_{m+1}^{\left(2\right)}\left(\mathrm{kr}\right)]P_m\left(\cos {\mathrm{\&theta;}}_s\right)k---\left(14\right)$

$v_{{\mathrm{\&theta;}}_{s}s}=\frac{k}{\mathrm{\&rho;\&omega;r}}\underset{m=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{(-1)}^{m+1}(2m+1)\frac{{\mathrm{mj}}_{m-1}\left(\mathrm{ka}\right)-(m+1)j_{m+1}\left(\mathrm{ka}\right)}{{\mathrm{mh}}_{m-1}^{\left(1\right)}\left(\mathrm{ka}\right)-(m+1)h_{m+1}^{\left(1\right)}\left(\mathrm{ka}\right)}{h}_m^{\left(1\right)}\left(k{r}_0\right)h_m^{\left(1\right)}\left(\mathrm{kr}\right)\mathrm{sign}\left(\sin {\mathrm{\&theta;}}_s\right)P_m^{\left(1\right)}\left(\cos {\mathrm{\&theta;}}_s\right)---\left(15\right)$

Can obtain plane wave incident directive property when test by formula (10) ~ (15), vector hydrophone receives signal and is followed successively by in the subsurface buoy:

p＝p _in+p _s (16)

v _r＝v _rin+v _rs (17)

$v_{{\mathrm{\&theta;}}_s}=v_{{\mathrm{\&theta;}}_s\mathrm{in}}+v_{{\mathrm{\&theta;}}_{s}s}---\left(18\right)$

From formula (7) ~ formula (9), and formula (16) ~ formula (18) as can be known, and incident wave and scattering wave have certain weight proportion relation in the acoustic pressure that the submerged buoy system vector hydrophone receives and the vibration velocity information.If during spherical wave incident when the proportionate relationship of corresponding incident wave and scattering wave and plane wave incident the proportionate relationship of corresponding incident wave and scattering wave suitable, and satisfy incident wave component much larger than the scattering wave component, then utilize spherical wave still can carry out the test of acoustics directive property to complicated vector hydrophone system as incident wave.

Such as Fig. 5-shown in Figure 8, four figure have provided under plane wave and the spherical wave incident condition spherical absolute hard baffle successively to vector hydrophone acoustics directive property impact analysis result, the amplitude relation of scattering wave and incident wave under Fig. 5 and Fig. 7 corresponding flat ripple and the spherical wave incident condition wherein, vector hydrophone directive property test result under Fig. 6 and Fig. 8 corresponding flat ripple and the spherical wave incident condition.As can be seen from the figure, can equivalence be the plane wave test result in certain angle scope endosphere ground roll test result.

In the 3rd step, low frequency/very low frequency (VLF) sound source transmission frequency is f ₀Test signal.

The 4th step, according to the subsurface buoy rotation angle range, rotate whole submerged buoy system to angle θ, the transmission frequency of real time record vector hydrophone sound pressure channel, each vector passage is f ₀The time signal, process to obtain subsurface buoy vector hydrophone low frequency/very low frequency (VLF) acoustics directive property through postposition.

Fig. 9 has provided the rearmounted disposal route of vector hydrophone reception signal when pond, directive property near field is tested, the acoustic pressure p when namely the anglec of rotation is θ (t) and vibration velocity signal v _x(t) and v _y(t) after processing (or zoomFFT processes), Fast Fourier Transform (FFT) FFT obtains corresponding amplitude Estimation:

A _p(f)＝FFT[p(t)] (19)

$A_{v_x}\left(f\right)=\mathrm{FFT}\left[v_x\left(t\right)\right]---\left(20\right)$

Continue the rotation submerged buoy system obtain [ _θ1, θ ₂] vector hydrophone in the angular range receives signal amplitude A accordingly _p(f, θ), $A_{v_x}(f,\mathrm{\&theta;})$ With $A_{v_y}(f,\mathrm{\&theta;}).$

Polar form shows A _p(f, θ),

With Can realize the test of submerged buoy system vector hydrophone directive property.

Claims (5)

1. the pond method of testing of one kind large-scale subsurface buoy vector hydrophone frequency acoustic directive property is characterized in that:

(1) submerged buoy system is laid on the center, pond, low frequency/very low frequency (VLF) sound source is laid on the vector hydrophone that makes in the submerged buoy system is in sound source near field and vector hydrophone center and sound source and is in the same degree of depth that lays, namely vector hydrophone position sound field is spherical wave expanding change rule;

(2) according to the size of large-scale submerged buoy system, but and the equivalence condition of spherical wave test result and plane wave test result, determine the rotation angle range of submerged buoy system;

(3) rotate whole submerged buoy system with the slow-speed of revolution, real time record vector hydrophone sound pressure channel, the signal when transmission frequency is f0 obtain subsurface buoy vector hydrophone low frequency/very low frequency (VLF) acoustics directive property through the postposition processing.

2. the pond method of testing of large-scale subsurface buoy vector hydrophone frequency acoustic directive property according to claim 1 is characterized in that: the submerged buoy system rotation is to rotate centered by the vector hydrophone center.

3. the pond method of testing of large-scale subsurface buoy vector hydrophone frequency acoustic directive property according to claim 1 and 2 is characterized in that: the selection of speed 1deg/s of described slow-speed of revolution rotation.

4. the pond method of testing of large-scale subsurface buoy vector hydrophone frequency acoustic directive property according to claim 1 and 2 is characterized in that: the described rearmounted method of processing comprises: the acoustic pressure p the when anglec of rotation is θ (t) and vibration velocity signal v _x(t) and v _y(t) after Fast Fourier Transform (FFT) FFT processing or zoomFFT processing, obtain corresponding amplitude Estimation:

A _p(f)＝FFT[p(t)]

$A_{v_x}\left(f\right)=\mathrm{FFT}\left[v_x\left(t\right)\right]$

Continue the rotation submerged buoy system and obtain [θ ₁, θ ₂] vector hydrophone in the angular range receives signal amplitude A accordingly _p(f, θ), $A_{v_x}(f,\mathrm{\&theta;})$ With $A_{v_y}(f,\mathrm{\&theta;});$

Polar form shows A _p(f, θ),

With Namely realize the test of submerged buoy system vector hydrophone directive property.

5. the pond method of testing of large-scale subsurface buoy vector hydrophone frequency acoustic directive property according to claim 3 is characterized in that: the described rearmounted method of processing comprises: the acoustic pressure p the when anglec of rotation is θ (t) and vibration velocity signal v _x(t) and v _y(t) after Fast Fourier Transform (FFT) FFT processing or zoomFFT processing, obtain corresponding amplitude Estimation:

A _p(f)＝FFT[p(t)]

$A_{v_x}\left(f\right)=\mathrm{FFT}\left[v_x\left(t\right)\right]$

Continue the rotation submerged buoy system obtain [ _θ1, θ ₂] vector hydrophone in the angular range receives signal amplitude A accordingly _p(f, θ), $A_{v_x}(f,\mathrm{\&theta;})$ With $A_{v_y}(f,\mathrm{\&theta;});$

Polar form shows A _p(f, θ),

With

Namely realize the test of submerged buoy system vector hydrophone directive property.

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