JP4886439B2 - Sound source exploration method and apparatus - Google Patents

Description

  The present invention relates to a sound source exploration technique for detecting the position of a noise generation source caused by an object through which a fluid such as air flows like a rotary impeller in a rotary blower or a compressor.

  Fluid pressure devices that convert mechanical energy into fluid energy such as air include blowers, compressors, and vacuum pumps. Fans with a pressure ratio that is the ratio of discharge pressure to suction pressure are less than 1.1. And a blower having a pressure ratio of 1.1 or more and less than 2, and the compressor is a fluid pressure device that pressurizes air or gas to a pressure ratio of 2.2 or more. These fluid pressure devices have a rotating impeller such as a fan blade, that is, a rotating blade, in order to convert the mechanical energy from the motor into fluid energy by being rotationally driven by a motor.

  Since noise is generated from the rotating impeller when the fluid pressure device is operating, in order to design a fluid pressure device with excellent quietness, it is necessary to detect where the noise is generated from the rotating impeller. It is necessary. The acoustic holography method and the sound intensity method are used to detect the position of a noise source due to the surface of an object such as a rotating impeller or ambient air separated from the surface. These acoustic holography method and sound intensity method are used. In the Citi method, it is difficult to accurately detect the noise source when the object to be measured is moving or rotating at high speed.

Patent Document 1 describes a technique in which a sound source is probed by obtaining a distance from a noise generation source to a noise generation source based on a time difference from the noise generation source to two microphones.
JP 2002-333367 A

  However, this technique requires measurement using a wind tunnel in the absence of wind speed distribution, and is limited to the analysis of two-dimensional blades. It is difficult to analyze an object that has a difference in wind speed distribution between parts. In addition, as a conventional analysis method of a rotor blade, there is a method of measuring sound pressure of a two-dimensional coordinate by arranging a large number of microphones on an X-Y biaxial measurement surface. In this method, an assembly of microphones is used. When a large or omnidirectional microphone is used, the surrounding sound is also detected, and the sound source search accuracy is limited. Furthermore, in the sound source search method using only a microphone, what can be measured is only the sound pressure, and there is a drawback that, for example, the flow phenomenon occurring at the sound source position cannot be captured.

  An object of the present invention is to make it possible to detect with high accuracy the position of noise generated by a fluid flowing from an object to its surface or a surrounding space spaced from the surface.

  An object of the present invention is to make it possible to detect with high accuracy the position and flow structure of noise generated by a fluid flowing from a rotary impeller to its surface or a surrounding space spaced from the surface.

  The sound source search method of the present invention is a sound source search method for detecting a position of a noise source generated from the rotary impeller under a state in which an air flow is generated by rotating the rotary impeller, Based on the signal from the position detection means for supplying the visible particles from the particle generator to the periphery of the car to fill the periphery of the rotary impeller with the visible particles and detecting the position of the rotary impeller The measurement part is irradiated with light from the light source, and images paired with at least two of the measurement parts are paired in synchronization with the light irradiation, and are taken a plurality of times by the photographing means, and each of the photographing means is used. The sound pressure from the measurement site at the time of imaging is measured with a microphone, and the fluid velocity vector is calculated by the particle image velocimetry based on the image captured by the imaging means The sound source distribution map is calculated by calculating the cross-correlation between the sound pressure and the air velocity based on the sound pressure measured by the microphone and the fluid velocity vector, and the sound source distribution map is output to the sound source distribution map output unit. It is characterized by that.

  The sound source search method of the present invention is a sound source search method for detecting the position of a noise source generated from the measurement object under a state in which a fluid is flowed through the measurement object, and is directed toward the measurement object. The visualization object is supplied into the fluid to fill the object to be measured with the visualization particle, and at least two of the parts to be measured irradiated from the light source to the object to be measured are paired with the imaging means a plurality of times. Take a picture, measure the sound pressure from the part to be measured at the time of each photographing by the photographing means with a microphone, and calculate the fluid velocity vector by the particle image velocimetry or the like based on the image photographed by the photographing means And calculating a sound source distribution map by calculating a cross-correlation between the sound pressure and the air velocity based on data of the sound pressure measured by the microphone and the fluid velocity vector, And outputs a cloth map to the sound source distribution map output section.

  The sound source exploration device according to the present invention is a sound source exploration device that detects the position of a noise source generated from the rotating impeller under a state in which an air flow is generated by rotating the rotating impeller. Based on a particle generator for supplying visualization particles to the periphery of the vehicle and filling the periphery of the rotary impeller with visualization particles, a position detection unit for detecting the position of the rotary impeller, and a signal from the position detection unit A light source for irradiating the measurement site of the rotary impeller with light, and an imaging means for imaging a pair of images of at least two of the measurement sites multiple times with a time difference in synchronization with the light irradiation; A microphone for measuring the sound pressure from the measurement site at the time of each imaging by the imaging means, and a fluid velocity vector by a particle image velocimetry or the like based on an image taken by the imaging means A fluid velocity vector computing unit for computing, a map computing unit for computing a sound source distribution map by cross-correlation calculation of sound pressure and fluid velocity based on data of the sound pressure measured by the microphone and the fluid velocity vector, And a sound source distribution map output unit that outputs a sound source distribution map.

  The sound source exploration device of the present invention is a sound source exploration device that detects a position of a noise source generated from the measurement object under a state in which a fluid is flowed through the measurement object, and flows toward the measurement object. A particle generator for supplying visualized particles in a fluid to be filled with the visualized particles, a light source for irradiating light on a specific measured portion of the measured object, and synchronization with light irradiation An imaging unit that images a pair of images of at least two of the measurement sites with a time difference, and a microphone that measures a sound pressure from the measurement site during each imaging by the imaging unit; A fluid velocity vector computing unit that computes a fluid velocity vector by a particle image flow velocity measurement method based on an image photographed by the photographing means, sound pressure data measured by the microphone, and the fluid A map calculation unit that calculates a sound source distribution map by calculating a cross-correlation between sound pressure and fluid velocity based on a degree vector, and a sound source distribution map output unit that outputs the sound source distribution map to a sound source distribution map output unit. Features.

  The fluid velocity vector is calculated by the PIV method, that is, the particle image velocimetry, based on the image of the measurement site, and the cross-correlation is based on the sound pressure data from the measurement site and the fluid velocity vector data at the time of imaging. Since the sound source distribution map is calculated, it is possible to detect the position of the noise source at the measurement site with high accuracy and to determine the fluid flow phenomenon and noise generation mechanism in the noise source. Can do.

  The object to be measured can be a fixed object as long as fluid flows around it, and can also be a rotating impeller such as a fan blade. When a rotating impeller is used as an object to be measured, an image of the measured part is taken at every predetermined rotation, and the sound pressure from the measured part at the time of photographing is measured, so that noise is generated by a sound source distribution map due to changes over time. The position of the source can be detected with high accuracy.

  When exploring the position of a noise source caused by a liquid flowing along an object placed in a liquid such as water, an underwater microphone or the like is used to measure the sound pressure during image capture. It will be.

  FIG. 1 is a schematic perspective view showing a sound source searching device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a control circuit of the sound source searching device of FIG.

  An object to be measured is a fan blade used for a blower, that is, a rotary impeller 10. The rotary impeller 10 is attached to a main shaft 12 of a servo motor 11 disposed in a measurement chamber and is driven to rotate. . The rotary impeller 10 is rotationally driven in the direction indicated by the arrow R by the servo motor 11 and generates an air flow in the direction indicated by the arrow B. In order to detect the rotational position of the rotary impeller 10, a reflective film 13 is attached to the rotary impeller 10, a light emitting element that irradiates light toward the reflective film 13, and reflection from the reflective film 13. A photosensor 14 provided with a light receiving element that receives light is disposed to face the rotating impeller 10, and the light receiving element of the photosensor 14 receives reflected light from the reflecting film 13, thereby rotating the impeller. 10, the position of each part in the rotational direction is detected.

  Smoke is supplied from the smoke generator 15 as a visualization particle generator into the measurement chamber, and the smoke fine particles P generated by the smoke generator 15 are smoke particles having an average particle diameter of 1 μm. As indicated by the arrow S, it is supplied to the airflow toward the rotary impeller 10 and is almost uniformly filled around and in the vicinity of the rotary impeller 10.

  In order to irradiate the laser beam toward the measurement site A of the rotary impeller 10, the laser light emitting device 16 is arranged as a light source so as to face the measurement site A. As this laser light emitting device 16, a YAG laser using yttrium aluminum garnet as a base and Nd ions as an active catalyst is used. The laser light emitting device 16 has two laser light generating head portions, and for example, 5 μS each other. The laser beam is irradiated toward the measurement site A with a time difference of (seconds). In order to capture an image of the measurement site A when the laser light is emitted from the laser light emitting device 16, a CCD camera 17 as an imaging unit is arranged facing the measurement site A.

  In order to detect the sound pressure from the site A to be measured, a microphone 18 is disposed facing the site A to be measured. The microphone 18 is disposed on the negative pressure side of the rotary impeller 10 at a distance of 25 to 50 mm from the rotary impeller 10 so as not to be affected by the wind pressure.

  The microphone 18 can also be used to determine the position of the site A to be measured, which seems to be a sound source. In order to determine the position of the measurement site A, the microphone 18 is mounted on a table that moves in the three-axis directions, the rotating impeller 10 is rotated at, for example, 2000 rpm, and the sound pressure is calculated from the signal from the microphone 18. The sound pressure Pa (Pascal) is calculated by the following equation (1).

Here, N is the number of measurement points, Xi is the microphone voltage value, x bar is the microphone voltage average value, and C is the conversion coefficient from the voltage value to the sound pressure Pascal.

  By measuring the sound pressure from a large number of parts with the microphone 18, the part with the highest sound pressure can be roughly set as the measurement area, that is, the measurement part A.

  As shown in FIG. 2, the output signal from the photosensor 14 is sent to the pulse generator 19, and when the reflection film 13 passes in front of the photosensor 14 with the rotation of the rotary impeller 10, A detection signal from the sensor 14 is sent to the pulse generator 19. A trigger signal is sent from the pulse generator 19 to the laser light emitting device 16 and the CCD camera 17, and a trigger signal is also sent to an A / D converter 20 for converting an analog signal from the microphone 18 into a digital signal. When the measurement site A is at a position facing the laser light emitting device 16, the laser light is irradiated with a time difference of 5 μS from the two laser light generating heads provided in the laser light emitting device 16 based on the trigger signal. The image is irradiated toward the measurement site A, and an image of the measurement site A that is a pair of two images at this time difference is captured by the CCD camera 17.

  Electric power is supplied to the servo motor 11, the laser light emitting device 16, the CCD camera 17 and the microphone 18 from a drive control unit (not shown), and the laser light emitting device 16 and the CCD camera 17 are received by a signal from the pulse generator 19. And the operation of the A / D converter 20 is controlled. The servo motor 11 is provided with an encoder that generates a pulse signal for controlling the rotation speed. A signal from the encoder is sent to the controller 21 so that the rotation speed of the servo motor 11 is precisely controlled. The controller 21 includes a microprocessor CPU that calculates control signals, a ROM that is a memory that stores control programs, arithmetic expressions, data, and the like, and a RAM that is a memory that temporarily stores data. Has input / output ports.

  The controller 21 receives a photographing signal from the CCD camera 17 and a measurement signal from the microphone 18 converted into a digital signal via the A / D converter 20, and each data is a data recording unit in the controller 21. To be stored in.

  FIG. 3 is a time chart showing the operation timing of the CCD camera 17 and the microphone 18 based on the signal from the photosensor 14. As shown in FIG. 3, the pulse generator 19 outputs the first pulse signal when the delay time T1 elapses after the photosensor 14 detects the reflection film 13, and 5 μm after the first pulse signal is output. When elapses, the second pulse signal is output. Based on these pulse signals, laser light is irradiated with a time difference of 5 μm from the two laser generating heads incorporated in the laser light emitting device 16, and the CCD camera 17 captures two images A1, A2 at this time difference, Each image data is stored in a memory such as a RAM in the controller 21.

  When the photosensor 14 is turned on, an operation signal is sent to the A / D converter 20 and the sound pressure data of the analog signal measured by the microphone 18 over a predetermined T2 time is converted into a digital signal by the A / D converter 20, and the controller 21 is stored in the memory. The T2 time is set to 626 μS, for example, and the sound pressure from the measurement site A at the time of camera photographing is measured. However, this time T2 can be set to any time between 5 and 2000 μS. Since the microphone 18 is arranged at a predetermined distance from the rotary impeller 10 as described above, it takes T3 time for noise to reach the microphone 18 from the rotary impeller 10. The noise generated from the measured image corresponds to the sound pressure after T3 time. When the microphone 18 is separated from the measurement site A by 30 mm, the delay time T3 becomes 87 μS.

  The rotary impeller 10 is driven to rotate by a servo motor 11. A pair of images are captured every time the measurement site A becomes a laser light irradiation position by a signal from the photosensor 14, and the sound pressure is measured by the microphone 18. . For example, when the rotary impeller 10 is rotated at a speed of 2000 rpm, a pair of images is captured every time the measurement site A becomes a laser beam irradiation position by a signal from the photosensor 14, and then about 0 is obtained. Repeat the operation of taking a pair of images every time the measurement site A becomes the laser light irradiation position by a signal from the photosensor 14 immediately after 2S has elapsed, and shoot a total of 1500 images, for example. Store data in memory. In the same manner, 1500 sound pressure data at the time of image capturing are also stored in the memory.

  Based on the data of the two images A1 and A2 that make a pair stored in the memory, the fluid velocity vector in the measurement site A is converted into the fluid velocity vector calculation unit in the controller 21 by PIV (Particle Image Velocimetry), that is, the particle image velocimetry. Is calculated by The fluid velocity vector is calculated for two-dimensional vectors of u (axial direction) and v (radial direction) from two pairs of images.

  This particle image velocimetry is a well-known velocity measurement method for fluids such as air and water. Fine particles that move at the same speed as the fluid, that is, visualized particles, are mixed in the flow, and the velocity of the particles is imaged. By measuring with the measurement method, the distribution of velocity and direction of the fluid itself, that is, the fluid velocity vector can be obtained. Particle image velocimetry includes two-dimensional PIV method and three-dimensional PIV method. In two-dimensional PIV method, an image centered on a measurement point is cut out from two particle images taken by time difference, and the particle There is a cross-correlation PIV method or the like in which the average moving amount is a flow velocity.

  In the sound source exploration apparatus shown in FIG. 1, the two-dimensional fluid velocity vector is calculated by the PIV method based on the data of the two images A1 and A2, but by using two CCD cameras 17, the circumference can be increased. A three-dimensional fluid velocity vector including the direction can be calculated. This is the three-dimensional PIV method.

  As described above, based on the fluid velocity vector data stored in the memory based on the 1500 images and the sound pressure data at the time of each photographing, the map computing unit of the controller 21 calculates the sound pressure and the fluid velocity. Perform cross-correlation calculation to calculate the sound source distribution map. The cross-correlation calculation (Rup) in the axial direction is performed by the following equation (2), and the cross-correlation calculation (Rvp) in the radial direction is performed by the following equation (3).

In equations (2) and (3), ui is an arbitrary axial velocity, u bar is an average velocity in the axial direction, pi is an arbitrary sound pressure, p bar is an average sound pressure, Vt is a blade tip velocity, and vi is an arbitrary radius. Directional velocity, v bar represents the average of radial velocity, u ′ represents axial velocity variation, v ′ represents radial velocity variation, p ′ represents sound pressure variation, and Vt represents blade tip peripheral velocity. p _rms indicates an execution value excluding the direct current component of the sound pressure, and is calculated by Expression (1).

  The sound source distribution map obtained in this way is an image showing the level distribution of the correlation between the fluid velocity, that is, the air flow velocity and the sound pressure, at the measurement site A, and is extracted from the controller 21 to the sound source distribution map output unit 22. . The sound source distribution map output unit 22 includes a display that displays the sound source distribution map on the screen, a printer that prints the sound source distribution map, or a storage medium such as a CDR that stores data of the sound source distribution map, and is shown in the sound source distribution map. The operator can determine the position of the sound source based on the height distribution of the correlation between the fluid flow velocity and the sound pressure.

  When such a sound source distribution map is obtained for a plurality of parts of the rotary blade, that is, the rotary impeller 10, the noise generation state and the generation mechanism of the rotary impeller 10 can be determined with high accuracy.

  The procedure for exploring a sound source by the sound source exploration device described above will be described. In a measurement room where light is not allowed to enter from the outside, such as in a dark room, the sound source of the rotary impeller 10 is opposed to a plurality of positions that are estimated. The noise generated from the rotary impeller 10 is measured using the microphone 18. At that time, the sound pressure is calculated in the controller 21 by sampling for a predetermined time, for example, 626 μS, based on the reference position signal from the photosensor 14. In this way, the region having the highest sound pressure level is examined, and that portion is set as a specific measured portion A to be measured. The sound pressure is calculated by the above equation (1).

  Next, the laser light emitting device 16 is arranged so that the laser beam reaches the measurement site A, the CCD camera 17 is arranged toward the measurement site A, the rotary impeller 10 is rotated, and the smoke generator 15 is rotated. The smoke, which is visualized fine particles, is supplied toward the air flow generated by the rotary impeller 10 to fill the measurement chamber with the smoke. Under this state, laser light is irradiated toward the measurement site A from the two laser light emitting head portions provided in the laser light emitting device 16 with a time difference of 5 μS, and the image is taken by the CCD camera 17. In synchronization with the photographing, the sound pressure from the measurement site A at the time of photographing is measured by the microphone 18.

  The rotary impeller 10 rotates at a speed of, for example, 2000 rpm, and the image of the measurement site A is photographed by the CCD camera 17 every about 0.2 S and the sound pressure at the time of photographing is measured in synchronization with the photographing. The reason for irradiating the laser beam every approximately 0.2S is that the charging time of the laser light emitting device 16 from one irradiation to the next irradiation requires about 0.2S. In this way, for example, 1500 times of image capturing and sound pressure measurement from the measurement site A during each image capturing were performed.

  Based on a pair of images captured by the CCD camera 17, the fluid velocity vector calculation unit of the controller 21 calculates the fluid velocity vectors u and v by the particle image flow velocity measurement method, and the sound pressure calculation unit of the controller 21 uses the microphone 18. The sound pressure is calculated based on the noise noise measured by the above. All of these calculations are performed on the captured image and the measured sound pressure. Next, a sound source distribution map is created by the above-described cross-correlation calculation based on the fluid velocity vector data and the sound pressure data.

  FIG. 4A is a velocity distribution diagram showing an example of velocity distribution obtained by the particle image velocimetry, and FIG. 4B shows cross-correlation calculation based on fluid velocity vector data and sound pressure data. It is a map figure which shows an example of the sound source distribution map obtained by this. In FIG. 4A, the darker shaded portion indicates that the fluid velocity is higher. In this velocity distribution diagram, the velocity of the fluid can also be indicated by an arrow, but the arrow mark is omitted in FIG. In FIG. 4B, the portion with a high concentration indicates that the correlation between the fluid velocity and the sound pressure is high, and the region with a high concentration indicates that the sound source is based on the high correlation. The sound source can be determined by displaying a sound source distribution map on a display or printing it with a printer. Thus, based on the sound pressure measured by the microphone 18 and the velocity vector of the fluid along the surface of the object whose particle flow is measured by the PIV method, the position of the sound source can be determined by the cross-correlation calculation. Therefore, the position of the noise source can be detected with high accuracy. In addition, the flow phenomenon of the sound source and the generation mechanism can be determined.

  The microprocessor of the controller 21 has functional units such as the fluid velocity vector calculation unit, the sound pressure calculation unit, and the map calculation unit described above, and each is stored in the ROM based on data sent to the controller 21. Calculated by an arithmetic expression. The controller 21 shown in FIG. 2 has a recording unit that stores the fluid velocity vector data and the sound pressure data that are sent in, and a function that calculates based on the respective data. The controller 21 may be provided with a function of supplying drive signals to the laser light emitting device 16, the CCD camera 17, and the microphone 18.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the position of the sound source from the rotary impeller 10 is detected. However, the position of the sound source generated from the surface of the object to be measured is fixed without rotating. May be detected. In the illustrated embodiment, the position of the sound source due to the airflow flowing through the object to be measured is detected, but the object placed in the liquid is the object to be measured and the sound source generated therefrom is detected. The position may be detected.

  In addition, the term of sound pressure in Equations (2) and (3) may include acoustic particle velocity in addition to the sound pressure by the microphone. For fluid velocity terms (u, v), not only normal velocity (m / s) but also dipole sound (wall pressure fluctuation) and quadrupole sound (airflow turbulence) generated from the turbulent boundary layer Can also be included.

For example, the dipole consonant uI _d and the quadrupole consonant uI _q are expressed by the following equations. In these equations, ρ is the density, r is the distance from the sound source, a is the speed of sound, L is the representative length of the sound source, and u is the fluid velocity.

  Furthermore, as the term of fluid velocity, the vorticity ω, the strain velocity eij, the Reynolds stress τ, and the turbulence intensity q obtained from the fluid velocity may be obtained.

1 is a schematic perspective view showing a sound source searching device according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a control circuit of the sound source searching device in FIG. 1. It is a time chart which shows the operation timing of a CCD camera and a microphone based on the signal from a photo sensor. (A) is a velocity distribution diagram showing an example of velocity distribution obtained by the particle image velocimetry, and (B) is obtained by cross-correlation calculation based on fluid velocity vector data and sound pressure data. It is a map figure which shows an example of a sound source distribution map.

Explanation of symbols

10 Rotating impeller (measurement object)
11 Servo motor 13 Reflective film 14 Photo sensor 15 Smoke generator (particle generator)
16 Laser light emitting device (light source)
17 CCD camera (photographing means)
18 Microphone 19 Pulse generator 20 A / D converter 21 Controller 22 Sound source distribution map output unit

Claims (4)

A sound source exploration method for detecting a position of a noise source generated from the rotary impeller under a state where an air flow is generated by rotating the rotary impeller,
Supplying visualization particles from a particle generator around the rotating impeller to fill the periphery of the rotating impeller with visualization particles;
Based on a signal from a position detecting means for detecting the position of the rotary impeller, the measurement site of the rotary impeller is irradiated with light from the light source and at least two of the measurement sites are synchronized with the light irradiation. Take a pair of images with a photographing means multiple times with a time difference,
The sound pressure from the measurement site at the time of each imaging by the imaging means is measured with a microphone,
A fluid velocity vector is calculated by a particle image velocimetry or the like based on an image photographed by the photographing means,
A sound source distribution map is calculated by calculating a cross-correlation between sound pressure and airflow velocity based on data of the sound pressure measured by the microphone and the fluid velocity vector,
A sound source search method, comprising: outputting the sound source distribution map to a sound source distribution map output unit. A sound source exploration method for detecting a position of a noise source generated from the measurement object under a state in which a fluid flows through the measurement object,
Supplying visualized particles in a fluid flowing toward the object to be measured to fill the object to be measured with the visualized particles;
Photographing a pair of images with at least two of the parts to be measured irradiated from the light source to the object to be measured multiple times by the photographing means,
The sound pressure from the measurement site at the time of each imaging by the imaging means is measured with a microphone,
A fluid velocity vector is calculated by a particle image velocimetry or the like based on the image captured by the imaging means,
A sound source distribution map is calculated by calculating a cross-correlation between sound pressure and airflow velocity based on data of the sound pressure measured by the microphone and the fluid velocity vector,
A sound source search method, comprising: outputting the sound source distribution map to a sound source distribution map output unit. A sound source exploration device that detects the position of a noise source generated from the rotary impeller under a state in which an airflow is generated by rotating the rotary impeller,
A particle generator for supplying visualization particles to the periphery of the rotating impeller and filling the periphery of the rotating impeller with visualization particles;
Position detecting means for detecting the position of the rotary impeller;
A light source that irradiates light to a measurement site of the rotary impeller based on a signal from the position detection unit;
An imaging means for imaging a pair of images with at least two of the measurement sites in synchronization with light irradiation, with a time difference;
A microphone for measuring sound pressure from the measurement site at the time of each imaging by the imaging means;
A fluid velocity vector computing unit that computes a fluid velocity vector by a particle image flow velocity measurement method or the like based on an image photographed by the photographing means;
A map calculation unit for calculating a sound source distribution map by cross-correlation calculation between sound pressure and fluid velocity based on data of the sound pressure measured by the microphone and the fluid velocity vector;
And a sound source distribution map output unit that outputs the sound source distribution map. A sound source exploration device that detects a position of a noise source generated from the measurement object under a state in which a fluid flows through the measurement object,
A particle generator for supplying visualized particles into a fluid flowing toward the object to be measured and filling the object to be measured with the visualized particles;
A light source that emits light to a specific measurement site of the measurement object;
An imaging means for imaging a pair of images at a time of at least two of the measurement sites in synchronism with light irradiation, with a time difference, and
A microphone for measuring sound pressure from the measurement site at the time of each imaging by the imaging means;
A fluid velocity vector computing unit that computes a fluid velocity vector by a particle image flow velocity measurement method or the like based on an image photographed by the photographing means;
A map calculation unit for calculating a sound source distribution map by cross-correlation calculation between sound pressure and fluid velocity based on sound pressure data measured by the microphone and the fluid velocity vector;
And a sound source distribution map output unit that outputs the sound source distribution map to a sound source distribution map output unit.