CN102980646B - Solid/fluid interfacial wave detecting device and method based on vector hydrophone - Google Patents

Abstract

The invention discloses a solid/fluid interfacial wave detecting device and a method based on a vector hydrophone and belongs to the technical field of ultrasonic testing and analysis. A signal exciting module generates square-wave pulse signals; an excitation signal radiation module generates interfacial waves which spread along an interface; the vector hydrophone in a signal receiving module is used for receiving the interfacial wave signals directly in water next to the interface, can obtain vector information of a sound field and improve noise jamming resistance and line spectrum detection capacity of a system, is fixed on a cross support composed of a double-shaft screw rod moving table, and moves accurately through an external control circuit; and finally a signal collecting module transmits the collected waveform data to a computer terminal for data processing and display. The method is flexible and convenient, detection at any position and array receiving of the solid/fluid interfacial waves can be achieved, the data connecting quantity is large, and the detecting accuracy and reliability can be improved greatly through post signal processing.

Description

Stream solid Interface Wave pick-up unit and detection method based on vector hydrophone

Technical field

The present invention relates to a kind of pick-up unit and detection method that flows solid Interface Wave, belong to Ultrasonic Detection and analysis technical field.

Background technology

Acoustic technique develop into that Nondestructive Evaluation, stress detect, defects detection provides a kind of effective means.Because stream solid Interface Wave has the advantages that amplitude is large, propagation loss is little, frequency dispersion is little, propagation in medium can reflect the many information in solid each medium of stream, permeability, density, smoothness such as solid dielectric, characteristic of crack, strength of fluid, impurity content etc., in recent years the application of incoming flow solid Interface Wave in fields such as geophysics, Non-Destructive Testings caused researchers' interest widely, be widely used at present dam monitoring, geologic prospecting, in the practical engineering application such as sediment charge detection.

Boundary wave mainly refers to the ripple of propagating along stream liquid/solid interface, and in stream liquid/solid interface, the main boundary wave existing refers to scholte ripple and leaky raleigh ripple.Because Scholte wave amplitude is large, energy is high, without the advantage such as the shear wave characteristic of low-frequency cut-off frequency, velocity of propagation and decay and sedimentary deposit is closely related, Scholte becomes the study hotspot in back analysis dielectric structure attribute field.At present, exciting with detection method of common stream solid Interface Wave has:

(1) laser pulse pulsed laser being sent vertical incidence after post lens focus becomes line source inspires surface wave on solid surface, and surface wave occurs to transform to form at stream liquid/solid interface place and flows solid Interface Wave.In the place application interference of light displacement vibration receiving system apart from excitaton source different distance, receive in real time and propagate the boundary wave arriving.As patent of invention---a kind of exciting microsize interface wave method and device (application number: 02112787.5).

(2) by solid is partly immersed in liquid, solid and liquid shape have a certain degree to obtain a suitable incident angle.At the solid surface that exposes liquid, with transducer, excite boundary wave, first at air-solid surface, form Rayleigh ripple, when rayleigh ripple propagates into air and is replaced by liquid surperficial, a part of ripple is reflected back, and a part of ripple is converted into scholte ripple and leaky rayleigh ripple.The solid other end in being immersed in liquid is placed receiving transducer reception interface ripple signal.

(3) utilize ultrasonic angle probe directly at solid surface, to excite boundary wave, the incident wave of launching due to ultrasonic angle probe forms an accurate incident angle in solid face, according to waveform transformation, can directly excite Rayleigh ripple and Scholte ripple.By receiving transducer, directly at stream liquid/solid interface, receive transmitting signal.

Above-mentioned the whole bag of tricks all can be realized the object that stream solid Interface Wave under specific circumstances detects to a certain extent, but the restriction of examined condition exists the problems such as checkout equipment is expensive, and detection efficiency is not high, and detection mode is single.

Summary of the invention

The object of the invention is to provide device and the detection method of the detection boundary wave that a kind of receive mode is flexible, automaticity is high.

The present invention adopts directly reception interface ripple signal in water of vector hydrophone, need to receiving equipment be installed at stream liquid/solid interface place, and detection mode is comparatively easy.For scalar nautical receiving set or traditional detection mode, can only accept the shortcoming of single signal, adopt vector hydrophone can measure each quadrature component of reflection acoustic pressure and quality vibration velocity simultaneously, reflect complete sound field information, the present invention can obtain more reliable underwater acoustic information by the processing module in later stage, than traditional single acoustic pressure information handling system, have good anti-coherent interference ability and line spectrum detectability, detecting reliability is high.The present invention can realize multimetering or array received by the movement of vector hydrophone, and data acquisition amount is large, and data-handling capacity is strong, and measuring accuracy improves greatly.Meanwhile, external control circuit of the present invention is directly controlled the movement of vector hydrophone, and automaticity is high, can according to actual conditions, adjust height and the position of nautical receiving set, is adapted at doing extensive popularization in the detection of Practical Project boundary wave.

At stream liquid/solid interface place, when fluid side and solid side are semi-infinite space medium, the displacement of plane wave should be zero, so the displacement potential function of the plane wave of propagating in stream-liquid/solid interface can be written as:

ψ2＝B2exp[-b2ky+ik(x-ct)] （3）

In formula (1) (2) (3), , there is not shear wave in the compressional wave wave potential function in fluid media (medium), so there is no shear wave potential function in fluid. be respectively compressional wave wave potential function and the shear wave potential function in solid dielectric, A with ψ ₁, A ₂, B ₂for Arbitrary Coefficient, k is propagation wave wave number (k=ω/c), and c is phase velocity. $a_1=\sqrt{1-c^2/c_{l1}^2};$ $a_2=\sqrt{1-c^2/c_{l2}^2};$ $b_2=\sqrt{1-c^2/c_{t2}^2};$ $c_{l1}=\sqrt{\frac{{\mathrm{\λ}}_1}{{\mathrm{\ρ}}_1}};$ $c_{l2}=\sqrt{\frac{{\mathrm{\λ}}_2+2{\mathrm{\μ}}_2}{{\mathrm{\ρ}}_2}}$ With $c_{t2}=\sqrt{\frac{{\mathrm{\μ}}_2}{{\mathrm{\ρ}}_2}}$ Be respectively longitudinal wave velocity and transverse wave speed in solid dielectric.λ, μ are the Lame's constant of medium, and ρ is density.The subscript 1,2 of above-mentioned various middle parameter represents respectively fluid, solid dielectric.

Boundary condition that should be satisfied while propagating at stream liquid/solid interface place in conjunction with plane wave:

(1) the interface Normal Displacement condition of continuity: u _y1=u _y2

(2) interface normal stress condition: δ _y1=δ _y2

(3) tractive stress condition: τ _xy1=τ _xy2=0

Again according to the relation of potential function and displacement and stress and potential function, the secular equation that can obtain flowing solid Interface Wave is:

${[{(c/c_{t2})}^2-2]}^2-4\sqrt{1-c^2/c_{l2}^2}\×\sqrt{1-c^2/c_{t2}^2}+\frac{{\mathrm{\ρ}}_1}{{\mathrm{\ρ}}_2}{(c/c_{t2})}^4\frac{\sqrt{1-c^2/c_{l2}^2}}{\sqrt{1-c^2/c_{l1}^2}}=0$

By finding out with the derivation of upper reaches solid Interface Wave secular equation, stream solid Interface Wave is propagated in two half infinite mediums, and communication process is not considered reflection and the refraction at interface, and is to propagate with the form of plane wave.Yet under actual conditions, be impossible accomplish solid and liquid infinity, therefore when designing, just should reduce this pick-up unit boundary reflection and refractive effect as far as possible, solid is cut into lamellar and stands in water and can be similar to and think that the thickness of solid side is greater than wavelength, and when piezoelectric ceramic piece accomplishes to think when enough narrow that the reflection from two borders will be left in the basket, so this device does not need directly to produce boundary wave by the pattern conversion of other ripples.

For achieving the above object, the technical solution used in the present invention is:

Signal emission module and signal receiving module are positioned over respectively the two ends of solid interface, signal stimulating module produces square-wave pulse signal pumping signal transmitter module and produces boundary wave, boundary wave is propagated along interface, by signal receiving module, received, wherein signal receiving module is by vector hydrophone direct reception interface ripple signal in pressing close to interfacial water, employing vector hydrophone can obtain the Vector Message of sound field, improves anti-noise jamming ability and the line spectrum detectability of system.Nautical receiving set is fixed on the cross frame being comprised of twin shaft screw mandrel slide unit, realizes nautical receiving set accurately move by external control circuit.This support also can be fixed many pieces of nautical receiving sets simultaneously, realizes the array received of nautical receiving set.Finally by signal acquisition module, the Wave data collecting is transferred to terminal and carries out data processing and demonstration.The method of this invention is flexible, can realize stream solid Interface Wave and detect at an arbitrary position and array received, and data acquisition amount is large, by the signal in later stage, is processed and can greatly be put forward accuracy of detection and reliability.

A pick-up unit for stream solid Interface Wave based on vector hydrophone, is characterized in that, comprises

One produces the pumping signal module of pulse excitation signal;

Under the incentive action of described pumping signal module, produce the signal emission module of boundary wave;

Signal receiving module, comprises vector hydrophone, directly receives the boundary wave signal of described signal emission module transmitting in water;

Signal acquisition module, gathers the signal that described signal receiving module receives;

External control circuit module, controls described vector hydrophone and moves;

Signal processes and displays module, processes and waveform demonstration the signal of described signal acquisition module transmission.

Described pumping signal module comprises take the square-wave pulse signal generation module that signal generator is core, the power amplifier module that the high frequency power amplifier of take is core, can produce the square-wave pulse signal of pulse width and changeable frequency; Described square-wave pulse signal generation module is connected with described power amplifier module, and the square-wave pulse signal that power amplifier module produces square wave signal generator module carries out power amplification.

In described signal emission module, adopt piezoelectric ceramic piece to excite boundary wave signal as transmitting transducer, the surrounding of piezoelectric ceramic piece transducer scribbles one deck epoxy resin, prevents energy emission and conduction.Piezoelectric ceramic piece is fixed on the two ends of interphase solid side with AB glue, and fixedly time, makes piezoelectric ceramic piece perpendicular to two sides adjacent with interphase.

Described signal emission module is fixedly installed on one end of the solid interphase solid side of stream and perpendicular to two sides adjacent with interphase.

Described signal receiving module comprises the vector hydrophone that receives underwater sound signal and the cross twin shaft screw mandrel slide unit that hangs vector hydrophone, and vector hydrophone can obtain more sound field information compared with traditional scalar nautical receiving set, improves the reliability that signal is processed.According to the pick-up condition of vector hydrophone: when satisfying condition ka < < 1, (wherein k represents wave number, a is the radius of nautical receiving set), and when the average density of vector hydrophone and aqueous medium density approach, the vibration velocity of vector hydrophone is identical with the vibration velocity amplitude of water particle, and phase place goes to zero.Therefore in the selection of vector hydrophone, global density is larger than liquid medium, is less than the wavelength of surveyed sound wave in size.Described vector hydrophone is suspended in liquid perpendicular to the solid interphase of stream and presses close to the solid interphase of stream.The height of cross twin shaft leading screw slide unit should not be too high, a little more than the water surface, can prevent the shake of nautical receiving set in moving process.Described cross twin shaft screw mandrel slide unit support will be reserved a plurality of hanging apparatus and can hang many pieces of nautical receiving set equipment, realizes hydrophone array and receives.

By described external control circuit module controls twin shaft screw mandrel slide unit, drive vector hydrophone to move; External control circuit module, by the identical two groups of installation compositions of structure, is controlled respectively the accurate movement of vector hydrophone in X-axis and Y direction; Each group device drives lead screw transmission that slide unit is moved by a stepper motor.

Described signal acquisition module comprises integrated operational amplifier, high-speed a/d modular converter, FPGA High-speed Control module and terminal.Wherein, high-speed a/d modular converter directly gathers the signal from operational amplifier by wired mode, by analog signal figure; FPGA High-speed Control module is changed the data storing of generation to the SRAM(Static RandomAccess Memory of terminal, i.e. static memory by IO port controlling high-speed a/d modular converter and by high-speed a/d modular converter) in; FPGA High-speed Control module by RS232 serial ports by the data reading in SRAM and transfer in computing machine; The direct reading out data of host computer of terminal also carries out algorithm process and the procreation work in later stage.

Described signal processes and displays module is that terminal is processed, and comprises for optimizing the velocity of wave shaping Algorithm module of nautical receiving set signal and for multiplying processing module and the display module of other underwater acoustic information.Can improve like this ability and the speed of data processing, reduce power consumption and the volume of pick-up unit, improve the reliability detecting.

A detection method for stream solid Interface Wave based on vector hydrophone, is characterized in that, comprises following steps:

(1) solid is cut into rectangular-shaped laminar, usings face that the length of rectangular parallelepiped and thickness edges form as bottom surface, solid block is stood in tank;

(2) piezoelectric ceramic piece is made into arrowband rectangular-shaped as transmitting transducer, piezoelectric ceramics length of a film and wide ratio are 4:1; Piezoelectric ceramic piece is arranged in signal emission module, and the length of piezoelectric ceramic piece is parallel with the solid interfacial narrow limit of stream; Signal emission module is fixed on one end of the solid interphase solid side of stream, and in fixing process, makes piezoelectric ceramic piece perpendicular to two sides adjacent with interface; At the piezoelectric ceramic piece fixing, be coated with one deck epoxy resin around;

(3) cross twin shaft screw mandrel slide unit support is installed in the both sides of solid, the top of support is higher than the liquid level in tank; The position, center of adjusting X-axis and Y-axis make its in flow admittedly interfacial directly over, and the distance of a wavelength of distance signal transmitter module;

(4) one or more vector hydrophones are suspended on twin shaft screw mandrel slide unit, adjust the position of vector hydrophone, make vector hydrophone vertical hanging in pressing close to interfacial liquid, press close to interphase but do not fit with solid, guarantee moving freely of nautical receiving set;

(5) adjust the pulse width of pumping signal module output square-wave signal, making the pulse width of pumping signal is 1/2 of piezoelectric ceramic piece rated frequency, makes the changes in amplitude of detection signal reach maximal value;

(6) by described pumping signal module pumping signal transmitter module, produce boundary wave signal;

(7) described vector hydrophone receives the boundary wave signal of described signal emission module transmitting;

(8) signal by upper computer software control signal acquisition module, vector hydrophone being received gathers, and then by terminal, the signal collecting is processed and the display by terminal shows;

(9) by external control circuit, control twin shaft screw mandrel slide unit and move, drive the movement of vector hydrophone, after the motion of vector hydrophone is static in water, the process of repeating step (5)-(8).

The beneficial effect that the present invention reaches:

The invention provides a kind of stream solid Interface Wave pick-up unit and detection method based on vector hydrophone.The wave propagation of stream liquid/solid interface is mainly because sound wave is coupled at stream liquid/solid interface place.Leaky Rayleigh ripple in stream-solid Interface Wave waveform, its energy is mainly to concentrate on solid surface, but in communication process constantly to emittance in fluid; And its energy of Schotle ripple mainly concentrates near the fluid of stream liquid/solid interface, amplitude is maximum, frequency dispersion is little; Therefore near liquid place stream liquid/solid interface exists a large amount of acoustic signals, adopt vector hydrophone direct reception in water just can realize the object of surveying boundary wave signal.Because vector hydrophone can obtain the acoustic pressure at some place of sound field and the quadrature component of particle vibration, by the signal in later stage, processed and can be obtained than scalar nautical receiving set or the single more complete sound field information of acoustic pressure detection system, this system can obtain higher anti-coherent interference ability and line spectrum detectability simultaneously.This device is without the duck eye of erecting equipment or preset placement receiving transducer in solid side in advance, simple and convenient.According to boundary wave, along the direction index decay of vertical two media interface, energy mainly concentrates on the propagation characteristic in the wavelength coverage of one, interface, and the present invention is the placement location of mobile vector nautical receiving set flexibly, is convenient to detect Optimal Signals.After once exciting, adjust simultaneously hydrophone position carry out on reception once, realized the signal in motion and received, the boundary wave signal propagation characteristics of reflection different time points.The present invention can form hydrophone array by placing many pieces of nautical receiving sets, improves received signal power.Receiving side signal formula of the present invention is flexible, can realize multiple spot and detect and array received, improves boundary wave accuracy of detection, and data-handling capacity is strong, and reliability is high.

The fixed point that the present invention controls nautical receiving set by external control circuit moves, the accurate distance and position of the different check points in location, automation degree of equipment is high, can adjust according to actual conditions the position height etc. of nautical receiving set simultaneously, dirigibility is higher, is conducive to the present invention's promoting the use of in actual applications.

Accompanying drawing explanation

Fig. 1 is pick-up unit schematic diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.Following examples are only for technical scheme of the present invention is more clearly described, and can not limit the scope of the invention with this.

As shown in Figure 1, stream solid Interface Wave pick-up unit of the present invention mainly contains 6 parts compositions: pumping signal module 1; Signal emission module 2; Signal receiving module 3; Signal acquisition module 4; Signal processes and displays module 5; External control circuit module 6.Signal emission module 2 adopts piezoelectric ceramic piece to produce boundary wave signal as transmitting transducer.For guaranteeing to produce boundary wave signal by a relatively large margin, square-wave pulse signal adjusting pulsewidth that pumping signal module 1 produces pulse width and changeable frequency are 1/2 of piezoelectric ceramic piece rated frequency.Selecting of piezoelectric ceramic piece is difficult too thick, by AB glue, be fixed on the two ends of interphase 102 solid 101 sides, and in fixing process, make it perpendicular to two sides adjacent with interface, finally at the piezoelectric ceramic piece fixing, be coated with one deck epoxy resin around and make it tightly surround piezoelectric ceramic piece, prevent conduction and reduce energy emission.

In signal receiving module 3, comprise vector hydrophone, preferred dimension and global density meet the vector hydrophone of system requirements, and principle is: global density is larger than liquid medium, are less than the wavelength of surveyed sound wave in size.The installation site of vector hydrophone is for being hung vertically in liquid 103, and the stream of highly trying one's best consolidates interphase 102 but not exclusively laminating can guarantee the flexible movement of nautical receiving set.Cross twin shaft leading screw slide unit 8 supports 9 that hang nautical receiving set are arranged on the both sides of solid, guarantee that vector hydrophone is in the accurate movement of X-axis and Y direction under the prerequisite of stability.The height of cross twin shaft leading screw slide unit 8 should not be too high, should prevent the shake of nautical receiving set in moving process.

Signal acquisition module 4 comprises integrated operational amplifier, high-speed a/d modular converter, FPGA High-speed Control module and terminal.By the PC control signal acquisition module acquisition interface ripple signal of terminal, and image data is saved in the SRAM of computing machine.

Then 5 pairs of data that collect of signal processes and displays module are processed result are shown by graphoscope.Utilize computing machine to carry out data processing and can improve data processing speed and processing power, reduce pick-up unit power consumption.

External control circuit module 6 is controlled twin shaft screw mandrel slide unit 8 and is driven vector hydrophone 3 to move; External control circuit module, by the identical two groups of installation compositions of structure, is controlled respectively the accurate movement of vector hydrophone in X-axis and Y direction; Each group device drives lead screw transmission that slide unit is moved by a stepper motor.

The detection method of the stream solid Interface Wave based on vector hydrophone of the present invention, specific implementation method is as follows:

1) solid 101 is cut into rectangular-shaped laminar, on thickness, is difficult for too greatly, can reduce reflection and refraction that ripple is propagated in solid as far as possible.Using the length of rectangular parallelepiped and the face of thickness edges formation as bottom surface, solid block is stood in tank 7;

(2) piezoelectric ceramic piece is made into the rectangular-shaped transmitting transducer in signal emission module 2 in arrowband, long and wide ratio is about 4:1 left and right, and thickness is as far as possible thin.Piezoelectric ceramic piece is arranged in signal emission module, and the length of piezoelectric ceramic piece is parallel with the solid interfacial narrow limit of stream; Signal emission module 2 is fixed on one end of interphase solid side, and in fixing process, makes piezoelectric ceramic piece perpendicular to two sides adjacent with interface; At the piezoelectric ceramic piece fixing, being coated with one deck epoxy resin around makes it tightly surround piezoelectric ceramic piece;

(3) cross twin shaft screw mandrel slide unit support 9 is installed, 9 two load support columns of support are fixed on the both sides of solid 101, and the top of support 9 is higher than the liquid side in tank 7.The position, center of adjusting X-axis and Y-axis make its in flow solid interphase 102 directly over, and approximately wavelength distance left and right of distance signal transmitter module 2.

(4) one or more vector hydrophones are suspended on twin shaft screw mandrel slide unit 8, adjust the position of vector hydrophone, be vector hydrophone vertical hanging in pressing close to the water of interphase 102, try one's best interphase 102 but not exclusively with solid laminating, the moving freely of assurance nautical receiving set;

(5) adjust the pulse width of pumping signal module 1 output square-wave signal, making the pulse width of pumping signal is 1/2 of piezoelectric ceramic piece rated frequency, makes the changes in amplitude of detection signal reach maximal value;

(6) by described pumping signal module 1 pumping signal transmitter module 2, be that piezoelectric ceramic piece produces boundary wave signal;

(7) vector hydrophone in signal receiving module 3 receives the boundary wave signal of the piezoelectric ceramic piece transmitting in signal emission module 2;

(8) signal by upper computer software control signal acquisition module, signal receiving module 2 being received gathers, and then by terminal, the signal collecting is processed and the display by terminal shows.

(9) by external control circuit, control twin shaft silk slide unit 8 and move, drive the movement of vector hydrophone, after the motion of vector hydrophone is static in water, repeat the process of (5)-(8).As adopt a plurality of nautical receiving sets to form the mode of hydrophone array reception interface ripple signal, in later stage signal processing, increase beam forming algoritic module.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, do not departing under the prerequisite of the technology of the present invention principle; can also make some improvement and distortion, these improvement and distortion also should be considered as protection scope of the present invention.

Claims (7)

1. a pick-up unit for the stream solid Interface Wave based on vector hydrophone, is characterized in that, comprises

One produces the pumping signal module of pulse excitation signal;

Under the incentive action of described pumping signal module, produce the signal emission module of boundary wave;

Signal receiving module, comprises vector hydrophone, directly receives the boundary wave signal of described signal emission module transmitting in water;

Signal acquisition module, gathers the signal that described signal receiving module receives;

External control circuit module, controls described vector hydrophone and moves;

Signal processes and displays module, processes and waveform demonstration the signal of described signal acquisition module transmission;

Described signal receiving module comprises the vector hydrophone that receives underwater sound signal and the cross twin shaft screw mandrel slide unit that hangs vector hydrophone, and described vector hydrophone is suspended in liquid perpendicular to the solid interphase of stream and presses close to the solid interphase of stream;

By described external control circuit module controls twin shaft screw mandrel slide unit, drive vector hydrophone to move; External control circuit module, by the identical two groups of installation compositions of structure, is controlled respectively the accurate movement of vector hydrophone in X-axis and Y direction; Each group device drives lead screw transmission that slide unit is moved by a stepper motor.

2. the pick-up unit of the stream solid Interface Wave based on vector hydrophone according to claim 1, it is characterized in that, described pumping signal module comprises take the square-wave pulse signal generation module that signal generator is core, the power amplifier module that the high frequency power amplifier of take is core; Described square-wave pulse signal generation module is connected with described power amplifier module.

3. the pick-up unit of the stream solid Interface Wave based on vector hydrophone according to claim 1, it is characterized in that, in described signal emission module, adopt piezoelectric ceramic piece to excite boundary wave signal as transmitting transducer, the surrounding of piezoelectric ceramic piece transducer scribbles one deck epoxy resin.

4. the pick-up unit of the stream solid Interface Wave based on vector hydrophone according to claim 1, is characterized in that, described signal emission module is fixedly installed on one end of the solid interphase solid side of stream and perpendicular to two sides adjacent with interphase.

5. the pick-up unit of the stream solid Interface Wave based on vector hydrophone according to claim 1, it is characterized in that, described signal acquisition module comprises integrated operational amplifier, high-speed a/d modular converter, FPGA High-speed Control module and terminal, described A/D modular converter is connected with integrated operational amplifier, and described FPGA High-speed Control module is connected with high-speed a/d modular converter and is connected with terminal by RS232 serial ports by IO port.

6. the pick-up unit of the stream solid Interface Wave based on vector hydrophone according to claim 1, it is characterized in that, described signal processes and displays module is that terminal is processed, and comprises for optimizing the velocity of wave shaping Algorithm module of nautical receiving set signal and for multiplying processing module and the display module of other underwater acoustic information.

7. a detection method for the stream solid Interface Wave based on vector hydrophone, is characterized in that, comprises following steps:

(1) solid is cut into rectangular-shaped laminar, usings face that the length of rectangular parallelepiped and thickness edges form as bottom surface, solid is stood in tank;

(2) piezoelectric ceramic piece is made into arrowband rectangular-shaped as transmitting transducer, piezoelectric ceramics length of a film and wide ratio are 4:1; Piezoelectric ceramic piece is arranged in signal emission module, and the length of piezoelectric ceramic piece is parallel with the solid interfacial narrow limit of stream; Signal emission module is fixed on one end of the solid interphase solid side of stream, and in fixing process, makes piezoelectric ceramic piece perpendicular to two sides adjacent with the solid interphase of stream; At the piezoelectric ceramic piece fixing, be coated with one deck epoxy resin around;

(3) cross twin shaft screw mandrel slide unit support is installed in the both sides of solid, the top of support is higher than the liquid level in tank; The position, center of adjusting X-axis and Y-axis make its in flow admittedly interfacial directly over, and the distance of a wavelength of distance signal transmitter module;

(4) one or more vector hydrophones are suspended on twin shaft screw mandrel slide unit, adjust the position of vector hydrophone, make vector hydrophone vertical hanging in pressing close to the solid interfacial liquid of stream, press close to the solid interphase of stream but do not fit with solid, guarantee moving freely of nautical receiving set;

(5) adjust the pulse width of pumping signal module output square-wave signal, the pulse width that makes pumping signal is piezoelectric ceramic piece rated frequency , make the changes in amplitude of detection signal reach maximal value;

(6) by described pumping signal module pumping signal transmitter module, produce boundary wave signal;

(7) described vector hydrophone receives the boundary wave signal of described signal emission module transmitting;

(8) signal by upper computer software control signal acquisition module, vector hydrophone being received gathers, and then by terminal, the signal collecting is processed and the display by terminal shows;

(9) by external control circuit, control twin shaft screw mandrel slide unit and move, drive the movement of vector hydrophone, after the motion of vector hydrophone is static in water, the process of repeating step (5)-(8).