JP7276022B2 - Anemometer and wind speed measurement method - Google Patents

Description

The present invention relates to an anemometer and an anemometer method.

Various types of measuring instruments are used as anemometers for measuring wind speed (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2001-231148

An object of the present invention is to provide a technique capable of measuring wind speed easily and accurately.

According to one aspect of the invention,
a columnar sensor having a predetermined Strouhal number;
a support that supports the sensor;
a sound collecting unit that collects wind noise from the sensor;
a frequency analysis unit configured to frequency-analyze the wind noise collected by the sound collection unit and obtain a wind sound spectrum;
a wind speed calculation unit that calculates a wind speed based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number;
has
The support is provided with an anemometer having a pair of struts supporting opposite ends of the sensor.

According to another aspect of the invention,
a step of collecting wind noise from a columnar sensor having a predetermined Strouhal number;
a step of frequency-analyzing the collected wind noise to obtain a wind noise spectrum;
calculating a wind speed based on the dominant frequency of the dominant peak in the wind sound spectrum and the Strouhal number;
has
In the step of collecting wind noise,
A wind speed measurement method is provided in which the wind noise is collected while the sensor is supported at both ends.

ADVANTAGE OF THE INVENTION According to this invention, a wind speed can be measured easily and accurately.

1 is a schematic configuration diagram showing an anemometer according to an embodiment of the present invention; FIG. FIG. 4 is a diagram showing dominant frequencies of wind noise with respect to wind speed; 4 is a flow chart showing a wind speed measurement method according to an embodiment of the present invention; It is a perspective view which shows the support|pillar which concerns on the modification 1 of one Embodiment of this invention. It is a sectional view showing the support concerning modification 2 of one embodiment of the present invention.

[Description of Embodiments of the Present Disclosure]
<Knowledge acquired by the inventor>
First, the knowledge obtained by the inventor will be described.

(For propeller type)
A propeller-type anemometer such as that disclosed in Patent Document 1 has, for example, a propeller and a movable part (motor) that rotates the propeller. When the propeller catches wind, the propeller rotates and generates an electromotive force in the moving part. This measures the wind speed based on the electromotive force.

However, in a propeller-type anemometer, the propeller may be affected by inertia. The inertia of the propeller could cause the measured wind speed to be faster or slower than the actual wind speed.

In addition, since friction occurs in the propeller bearings, the propeller response is slow, and there is a possibility that the propeller cannot follow sudden changes in wind speed.

(For ultrasonic type)
In addition to propeller-type anemometers, there are ultrasonic anemometers. An ultrasonic anemometer includes, for example, a palpation section having a transmission section that emits ultrasonic waves and a reception section that receives ultrasonic waves. While ultrasonic waves are being transmitted and received between the transmitter and receiver, when wind passes between them, the frequency of the ultrasonic waves changes slightly due to the Doppler effect. At this time, by detecting the shift in the frequency of the ultrasonic waves, the wind speed can be calculated based on the shift in frequency.

However, although the ultrasonic anemometer has a good response, it is necessary to improve the transmission and reception accuracy of ultrasonic waves at the palpable part. As a result, the anemometer is complicated or heavy, and the anemometer is expensive.

Therefore, there has been a demand for a technique that can easily and accurately measure the wind speed.

The present invention is based on the above knowledge discovered by the inventor.

<Embodiments of the Present Disclosure>
Next, embodiments of the present disclosure are listed and described.

[1] An anemometer according to an aspect of the present disclosure,
a columnar sensor having a predetermined Strouhal number;
a support that supports the sensor;
a sound collecting unit that collects wind noise from the sensor;
a frequency analysis unit configured to frequency-analyze the wind noise collected by the sound collection unit and acquire a wind sound spectrum;
a wind speed calculation unit that calculates a wind speed based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number;
has
The support section has a pair of pillars that support both ends of the sensor.
According to this configuration, the wind speed can be measured easily and accurately.

[2] In the anemometer described in [1] above,
Each of the pair of struts is thicker than the sensor.
According to this configuration, it is possible to suppress a decrease in wind speed measurement accuracy caused by wind noise from the support as noise.

[3] In the anemometer according to [1] or [2] above,
Each of the pair of pillars is configured in a prism shape.
According to this configuration, it is possible to suppress a decrease in wind speed measurement accuracy caused by wind noise from the support as noise.

[4] In the anemometer according to any one of [1] to [3] above,
Each of the pair of pillars has irregularities on its outer periphery that suppress the generation of Karman vortices more than the cylinder.
According to this configuration, it is possible to suppress a decrease in wind speed measurement accuracy caused by wind noise from the support as noise.

[5] In the anemometer according to any one of [1] to [4] above,
The sound collecting unit has directivity,
The direction in which the directivity of the sound collector is relatively high is directed toward the sensor.
According to this configuration, it is possible to suppress background noise from sources other than the sensor from being collected by the sound collector, and reduce noise caused by the background noise from sources other than the sensor.

[6] In the anemometer according to any one of [1] to [5] above,
The sensor is configured in a cylindrical shape.
According to this configuration, it is possible to suppress the adhesion of dirt and foreign matter to the outer peripheral surface of the sensor.

[7] In the anemometer according to any one of [1] to [6] above,
It has a rotation holding portion that holds at least the support portion so as to be rotatable in the horizontal direction so that the center axis of the sensor approaches perpendicular to the direction of the wind.
According to this configuration, a Karman vortex can be efficiently generated downstream of the sensor.

[8] In the anemometer according to any one of [1] to [7] above,
The axial length of the sensor is 700 mm or more.
According to this configuration, prominent peaks in the wind sound spectrum can be easily identified, and the dominant frequencies can be measured with high accuracy.

[9] In the anemometer according to any one of [1] to [8] above,
The thickness of the sensor is 5 mm or more and 20 mm or less.
According to this configuration, bending of the sensor can be suppressed. Also, the sensitivity of the sensor can be improved.

[10] A wind speed measurement method according to another aspect of the present disclosure includes:
a step of collecting wind noise from a columnar sensor having a predetermined Strouhal number;
a step of frequency-analyzing the collected wind noise to obtain a wind noise spectrum;
calculating a wind speed based on the dominant frequency of the dominant peak in the wind sound spectrum and the Strouhal number;
has
In the step of collecting wind noise,
The wind noise is collected while the both ends of the sensor are supported.
According to this configuration, the wind speed can be measured easily and accurately.

[Details of the embodiment of the present disclosure]
Next, one embodiment of the present disclosure will be described below with reference to the drawings. The present invention is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

<One embodiment of the present invention>
(1) Anemometer First, an anemometer according to an embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram showing an anemometer according to this embodiment.

As shown in FIG. 1, the anemometer 10 of the present embodiment includes, for example, a sensor (measurement column) 100, a support section 200, a sound collection section (microphone) 300, a rotation holding section 500, and an AD conversion section 410. , a frequency analysis unit 420 , a wind speed calculation unit 430 , a recording unit (data logger) 440 , and a display unit (monitor) 450 .

(sensor)
The sensor 100 is configured, for example, in a columnar shape. When wind blows from a direction that intersects the sensor 100 in the axial direction, an airflow vortex called a Karman vortex can be generated downstream of the sensor 100 . Wind noise having a specific dominant frequency can be generated by generating a Karman vortex. As will be described later, the wind speed can be obtained by measuring the dominant frequency of wind noise from the sensor 100 .

In the present embodiment, the sensor 100 is configured, for example, in a cylindrical shape and has a smooth arc-shaped (cylindrical) outer peripheral surface. In other words, the outer periphery of the sensor 100 is not provided with structures such as unevenness and linear bodies.

Moreover, the sensor 100 has a predetermined Strouhal number (St). The "Strohal number" referred to here means a constant of proportionality in which the dominant frequency of wind noise is proportional to the wind speed, and depends on the shape of an object and the like. As described above, when the sensor 100 is configured in a cylindrical shape, the Strouhal number is, for example, 0.18 or more and 0.22 or less. Note that when the sensor 100 is configured in a columnar shape, the Strouhal number is a substantially constant value regardless of the axial length of the sensor 100 or the thickness of the sensor 100 .

In this embodiment, the axial length of the sensor 100 is, for example, 700 mm or more, preferably more than 800 mm. When the axial length of the sensor 100 is less than 700 mm, for example, when the wind speed is 10 m/s or less, the wind noise spectrum emitted from the sensor 100 (hereinafter also referred to as the wind noise spectrum) has a prominent peak level. , there is a possibility that it will be below the background noise level (about 40 dB) of a normal urban area. For this reason, it becomes difficult to distinguish prominent peaks in the wind sound spectrum, and it may be difficult to improve the measurement accuracy of the dominant frequencies. On the other hand, in this embodiment, by setting the axial length of the sensor 100 to 700 mm or more, even when the wind speed is 10 m/s or less, for example, the peak level of the wind noise spectrum is reduced to that of a normal urban area. Background noise levels can be exceeded. As a result, prominent peaks in the wind sound spectrum can be easily identified, and the dominant frequencies can be accurately measured. Furthermore, by setting the axial length of the sensor 100 to more than 800 mm, the peak level of the wind noise spectrum can be made to exceed the background noise level even when the wind speed is 5 m/s or less, for example.

Note that the upper limit of the axial length of the sensor 100 is not particularly limited. However, if the length of the sensor 100 in the axial direction is excessively increased, the weight of the support section 200 also increases, possibly deteriorating the portability. Moreover, even if the axial length of the sensor 100 is increased, the level of the dominant peak does not change significantly. Therefore, it is considered practical if the axial length of the sensor 100 is 1500 mm or less.

Moreover, in the present embodiment, the thickness of the sensor 100 is, for example, 5 mm or more and 20 mm or less, preferably 10 mm or less. The "thickness of the sensor 100" here means the maximum thickness (maximum width) of the sensor 100 when the sensor 100 is anisotropic with respect to the central axis. On the other hand, "the thickness of the sensor 100" means the diameter of the sensor 100 when the sensor 100 is cylindrical as described above.

If the thickness of the sensor 100 is less than 5 mm, even if both ends of the sensor 100 are supported, the sensor 100 may bend when exposed to strong wind. Therefore, it may be difficult to improve the measurement accuracy when the wind speed is high. On the other hand, in the present embodiment, by setting the thickness of the sensor 100 to 5 mm or more, the bending of the sensor 100 can be suppressed even if the sensor 100 receives a strong wind. Thereby, the measurement accuracy can be improved even when the wind speed is high.

On the other hand, if the thickness of the sensor 100 exceeds 20 mm, the dominant level will also be low when the dominant frequency is reduced. Also, the slope of the dominant frequency with respect to the wind speed becomes gentle. Therefore, it may be difficult to improve the measurement accuracy of the dominant frequency, especially in a low wind speed region. On the other hand, in the present embodiment, by setting the thickness of the sensor 100 to 20 mm or less, it is possible to prevent the dominant level from simultaneously decreasing when the dominant frequency is decreased. In addition, it is possible to ensure that the slope of the dominant frequency with respect to the wind speed is equal to or greater than a predetermined value. These can improve the sensitivity of the sensor 100 . As a result, even in a low wind speed region, it is possible to improve the measurement accuracy of the dominant frequency.

(support part)
The support section 200 supports the sensor 100, for example. In this embodiment, the support section 200 has, for example, a pair of struts 220 and a connecting section 240 .

A pair of struts 220 support, for example, both ends of the sensor 100 . Thereby, bending of the sensor 100 can be suppressed.

The pair of supports 220 are, for example, erected in the vertical direction and support the sensor 100 in the horizontal direction. This makes it possible to stably support the long sensor 100 as compared with the case where the sensor 100 is supported along the vertical direction.

Also, each of the pair of struts 220 is thicker than the sensor 100, for example. Thereby, interference between the wind noise from the sensor 100 and the wind noise from the strut 220 can be suppressed. In addition, the support|pillar 220 is comprised here, for example in columnar shape.

The connecting portion 240 is configured in a columnar shape, for example, and connects the lower ends of the pair of supports 220 to each other. The axial length of the connecting portion 240 is, for example, equal to the axial length of the sensor 100 . The connection part 240 is provided parallel to the sensor 100, for example. Thereby, the gap between the pair of struts 220 can be fixed, and the bending of the sensor 100 can be suppressed.

(Sound collection part)
The sound collector 300 is configured to collect (acquire) wind noise from the sensor 100, for example. The sound collector 300 outputs an analog signal of wind noise collected from the sensor 100 .

The sound collector 300 has directivity, for example. The direction in which the directivity of the sound collector 300 is relatively high (the direction in which the sound collection sensitivity is high, the sensing section) is directed toward the sensor 100, for example. Thereby, noise caused by background noise other than the sensor 100 can be reduced. Furthermore, it is preferable that the direction in which the directivity of the sound collector 300 is relatively high is directed to the midpoint of the sensor 100 between the pair of supports 220, for example. As a result, noise caused by the strut 220 can be reduced.

(rotation holding part)
The rotation holding part 500 holds at least the support part 200 so as to be able to rotate in the horizontal direction, for example, so that the center axis of the sensor 100 approaches (preferably becomes) vertical to the wind direction. Thereby, a Karman vortex can be efficiently generated on the downstream side of the sensor 100 .

In this embodiment, the rotation holding part 500 horizontally rotates the sound collecting part 300 together with the support part 200 so that the sensitivity of the sound collecting part 300 to collect the wind noise from the sensor 100 is increased according to the direction of the wind. rotatably held. As a result, wind noise from the sensor 100 can be collected with high accuracy.

Specifically, the rotary holding section 500 has, for example, a rotating shaft 510 , a potentiometer 520 , a holding table 530 and wings 540 .

The rotating shaft 510 is, for example, erected in the vertical direction and configured to be rotatable in the circumferential direction.

The holding base 530 is provided rotatably around the rotating shaft 510 , for example, and holds the support section 200 and the sound collecting section 300 . Specifically, the holding table 530 is configured, for example, in a columnar shape, and the central portion of the holding table 530 is rotatably connected to the rotating shaft 510 . The holding table 530 holds the support part 200 so that the sensor 100 overlaps the rotating shaft 510 when viewed from the vertical direction, for example. A sound collector 300 is arranged at one end of the holding table 530 toward the sensor 100, for example.

Potentiometer 520 is connected, for example, between rotating shaft 510 and holding base 530 . The potentiometer 520 is configured, for example, to detect the rotation angle of the holding table 530 about the rotation axis 510 and output a signal based on the rotation angle.

The wing part 540 is provided on the holding base 530 , for example, and is configured to apply a rotational force around the rotating shaft 510 to the holding base 530 by receiving the wind. The wings 540 are arranged on the holding table 530 so as to be orthogonal to the axial direction of the sensor 100 when viewed from the vertical direction, for example. Accordingly, when the wing portion 540 receives the wind, the support base 530 can be rotated so that the center axis of the sensor 100 approaches perpendicular to the direction of the wind.

Also, the wing portion 540 is provided on the opposite side of the sound collector 300 with the sensor 100 interposed therebetween, for example, when viewed in the vertical direction. When the wing section 540 receives wind, the holding base 530 rotates so that the sound collecting section 300 is arranged on the windward side of the sensor 100 and faces the leeward side. As a result, it is possible to prevent the vibrating portion of the sound collecting portion 300 itself from vibrating due to the wind. As a result, erroneous detection of wind noise can be suppressed.

(AD converter)
The AD converter 410 is, for example, connected to the sound collector 300 and configured to convert an analog signal of wind noise output from the sound collector 300 into a digital signal.

(Frequency analysis part)
The frequency analysis unit 420 is connected to the AD conversion unit 410, for example, and based on the digital signal of the wind noise collected by the sound collection unit 300, frequency-analyzes the wind noise by fast Fourier transform, and acquires the wind sound spectrum. is configured as follows. The frequency analysis here is performed, for example, by 1/3 octave band analysis. 1/3 octave band analysis is a method of performing frequency analysis at each point obtained by dividing one octave of frequency into three.

Further, the frequency analysis unit 420 is configured, for example, to detect prominent peaks in the obtained wind noise spectrum and obtain the dominant frequencies of the peaks.

(Wind speed calculator)
The wind speed calculation unit 430 is configured, for example, to acquire the dominant frequency of the prominent peak in the wind sound spectrum from the frequency analysis unit 420, and to calculate the wind speed based on the dominant frequency and the Strouhal number.

Here, FIG. 2 is a diagram showing dominant frequencies of wind noise with respect to wind speed. FIG. 2 shows the case where the sensor 100 is cylindrical, the outside diameter of the sensor 100 is 7 mm, and the wind speed is increased at intervals of 2 m/s from 0 to 40 m/s. In FIG. 2, the horizontal axis is the wind speed, the left vertical axis is the dominant frequency, and the right vertical axis is the Strouhal number.

As shown in FIG. 2, the dominant frequency of wind noise caused by Karman vortices occurring downstream of the sensor 100 tends to be proportional to the wind speed. Even if the wind speed changes, the Strouhal number, which is a constant of proportionality, is almost constant.

Let f (Hz) be the predominant frequency of wind noise, D be the outer diameter (m) of the sensor 100, V be the wind velocity (m/s), and St be the Strouhal number. , is obtained by the following equation (1).

f=(V/D)×St (1)

Solving equation (1) for wind speed V yields equation (2) below.

V=fD/St (2)

The wind velocity V can be obtained from the equation (2) based on the dominant frequency f of the wind noise from the sensor 100 and the Strouhal number St set based on the shape of the sensor 100 .

(recording section)
The recording unit 440 is configured to record various data obtained by the anemometer 10, for example. Specifically, the recording unit 440 is connected to, for example, the AD conversion unit 410, the frequency analysis unit 420, the wind speed calculation unit 430, and the potentiometer 520 so as to be able to acquire data. The recording unit 440 stores, for example, audio data based on digital signals of wind noise, the wind noise spectrum and dominant frequencies analyzed by the frequency analysis unit 420, the wind speed calculated by the wind speed calculation unit 430, and the holding table 530 detected by the potentiometer 520. The rotation angle, ie the wind direction, etc. is recorded.

(Display part)
The display unit 450 is configured to display various data obtained by the anemometer 10, for example. Specifically, the display unit 450 is configured to display, for example, the wind sound spectrum and dominant frequencies, wind speed, and wind direction.

(2) Wind speed measurement method Next, the wind speed measurement method according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the wind speed measurement method according to this embodiment. A step is abbreviated as "S".

The wind speed measurement process of this embodiment includes, for example, a sound collection process S120, a frequency analysis process S140, and a wind speed calculation process S160.

(S120: sound collection step)
In the sound collection step S120, wind noise is collected from the columnar sensor 100 having a predetermined Strouhal number.

Specifically, first, wing portions 540 of rotation holding portion 500 receive the wind, so that holding table 530 is rotated so that the central axis of sensor 100 approaches perpendicular to the direction of the wind. After the holding base 530 is rotated to a predetermined position, the wind noise from the sensor 100 is collected using the sound collecting unit 300 .

At this time, wind noise from the sensor 100 is collected while both ends of the sensor 100 are supported by the support portions 200 .

At this time, the analog signal of the wind noise output from the sound collector 300 is converted into a digital signal by the AD converter 410 . After that, audio data based on the wind noise digital signal from the AD converter 410 is recorded in the recorder 440 .

Also, at this time, the rotation angle of the holding table 530 detected by the potentiometer 520 , that is, the wind direction is recorded in the recording unit 440 . In addition, the wind direction is displayed on the display unit 450 as necessary.

(S140: frequency analysis step)
After the sound collection step S120 is completed, the frequency analysis unit 420 performs frequency analysis on the collected wind noise to obtain a wind noise spectrum.

After obtaining the wind sound spectrum, a dominant peak is detected in the obtained wind sound spectrum, and the dominant frequency of the peak is obtained.

After obtaining the wind sound spectrum and dominant frequencies, the wind sound spectrum and dominant frequencies are recorded in the recording unit 440 . In addition, the wind noise spectrum and the dominant frequency are displayed on the display unit 450 as necessary.

(S160: wind speed calculation step)
After the frequency analysis step S140 is completed, the wind speed calculator 430 is used to calculate the wind speed using the above equation (2) based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number.

After calculating the wind speed, the wind speed is recorded in the recording unit 440 . Moreover, the wind speed is displayed on the display unit 450 as necessary.

By the above, the wind speed measurement process of this embodiment is complete|finished. Note that the cycle including the above-described sound collection step S120, frequency analysis step S140, and wind speed calculation step S160 may be repeated according to changes in wind direction and wind speed.

(3) Effects According to the Present Embodiment According to the present embodiment, one or more of the following effects can be obtained.

(a) In the anemometer 10 of this embodiment, a pair of struts 220 support both ends of the sensor 100 . By supporting both ends of the sensor 100, bending of the sensor 100 can be suppressed.

Here, consider the case where only one end of the columnar sensor is supported in the anemometer. In this case, since only one end of the sensor is supported, the other end of the sensor is not fixed. Therefore, when a strong wind blows against the sensor, the other end of the sensor may bend. Deflection of the sensor disturbs the Karman vortices that occur downstream of the sensor. If the Karman vortices are disturbed, wind noise caused by the Karman vortices will not be generated stably. If the wind noise is not stably generated, the peak of the wind noise spectrum becomes unclear. Therefore, it becomes difficult to accurately measure the dominant frequency of wind noise. As a result, if only one end of the sensor is supported, the wind speed measurement accuracy may be degraded.

In contrast, in the present embodiment, by supporting both ends of the sensor 100, even if a strong wind blows against the sensor 100, the bending of the sensor 100 can be suppressed. By suppressing the bending of the sensor 100, disturbance of the Karman vortices on the downstream side of the sensor 100 can be suppressed. By suppressing the turbulence of the Karman vortices, wind noise caused by the Karman vortices can be stably generated. By stably generating wind noise, the peak of the wind noise spectrum can be clarified. This makes it possible to accurately measure the dominant frequency of wind noise. As a result, it is possible to improve the measurement accuracy of the wind speed.

(b) By supporting both ends of the sensor 100 , the part to be measured of the sensor 100 can be separated from the joint between the sensor 100 and the column 220 by a predetermined distance. As a result, disturbance of the Karman vortices at the measurement point of the sensor 100 can be suppressed. As a result, it is possible to suppress a decrease in wind speed measurement accuracy caused by the connecting portion between the sensor 100 and the strut 220 .

(c) By using sound waves as wind noise from the sensor 100, the dominant frequencies in the wind noise spectrum can be measured without delay from the generation of the wind noise. This makes it possible to improve the measurement response speed of the wind speed compared to a propeller type anemometer.

(d) In this embodiment, the sensor 100 is simply a columnar member, and the anemometer 10 does not have a complicated measurement mechanism. As a result, the anemometer 10 of the present embodiment can be simplified and reduced in weight as compared with an ultrasonic anemometer. As a result, the cost of the anemometer 10 can be reduced.

According to (a) to (d), the wind speed can be measured easily and accurately in this embodiment.

(e) Each of the pair of struts 220 supporting the sensor 100 is thicker than the sensor 100; By making the strut 220 thicker than the sensor 100, the dominant frequency of the wind noise from the strut 220 can be made lower than the dominant frequency of the wind sound from the sensor 100 in the wind sound spectrum. Overlapping of sound peaks and wind noise from the sensor 100 can be suppressed. Thereby, interference between the wind noise from the sensor 100 and the wind noise from the strut 220 can be suppressed. As a result, it is possible to suppress a decrease in wind speed measurement accuracy caused by wind noise from the support 220 as noise.

(f) The sound collector 300 has directivity, and the direction in which the directivity of the sound collector 300 is relatively high is directed toward the sensor 100 . As a result, background noise from sources other than the sensor 100 can be suppressed from being collected by the sound collector 300, and noise caused by the background noise from sources other than the sensor 100 can be reduced. By reducing the noise, the peak of the wind noise spectrum can be clarified, and the dominant frequency of the wind noise can be measured with high accuracy. As a result, it is possible to stably improve the measurement accuracy of the wind speed.

(g) In this embodiment, the sensor 100 is configured in a cylindrical shape. As a result, it is possible to suppress adhesion of dirt and foreign matter to the outer peripheral surface of the sensor 100 compared to the case where a structure is provided on the outer periphery of the sensor 100 . As a result, the measurement accuracy of the anemometer 10 can be stably supported.

(h) The rotation holding part 500 holds at least the support part 200 so as to be rotatable in the horizontal direction so that the center axis of the sensor 100 approaches perpendicular to the wind direction. That is, the wind can be blown perpendicularly to the sensor 100 by rotating the rotation holding part 500 to a suitable position according to the direction of the wind. Thereby, a Karman vortex can be efficiently generated on the downstream side of the sensor 100 . Wind noise from the sensor 100 can be stably generated by efficiently generating Karman vortices. As a result, it is possible to stably improve the measurement accuracy of the wind speed.

(i) By setting the axial length of the sensor 100 to 700 mm or more, even when the wind speed is 10 m/s or less, the peak level of the wind noise spectrum exceeds the background noise level of a normal city area. be able to. As a result, prominent peaks in the wind sound spectrum can be easily identified, and the dominant frequencies can be accurately measured.

(j) By setting the thickness of the sensor 100 to 5 mm or more, the bending of the sensor 100 can be suppressed even if the sensor 100 receives a strong wind. Thereby, the measurement accuracy can be improved even when the wind speed is high. By setting the thickness of the sensor 100 to 20 mm or less, it is possible to prevent the dominant level from simultaneously decreasing when the dominant frequency is decreased. In addition, it is possible to ensure that the slope of the dominant frequency with respect to the wind speed is equal to or greater than a predetermined value. These can improve the sensitivity of the sensor 100 . As a result, even in a low wind speed region, it is possible to improve the measurement accuracy of the dominant frequency.

(4) Modifications of One Embodiment The above-described embodiment can be modified as in the following modifications, if necessary. Hereinafter, only elements different from the above-described embodiment will be described, and elements that are substantially the same as those described in the above-described embodiment will be given the same reference numerals, and descriptions thereof will be omitted.

(4-1) Modification 1 of one embodiment
Modification 1 of the present embodiment will be described with reference to FIG. 4A. FIG. 4A is a perspective view showing a column according to Modification 1 of the present embodiment.

As shown in FIG. 4A, in the anemometer 10 of Modified Example 1 of the present embodiment, the configuration of the strut 220 is different from that of the above-described embodiment.

In this modified example, each of the pair of support columns 220 is configured in a prism shape, for example. Here, the support 220 is configured in, for example, a quadrangular prism shape. Note that the number of corners of the strut 220 is not particularly limited. Also, the struts 220 may be rotationally symmetrical about the central axis, or may be rotationally asymmetrical.

According to this modified example, by configuring the support 220 in a prism shape, it is possible to suppress the generation of Karman vortices in the vicinity of the support 220 and suppress the generation of wind noise from the support 220 . By suppressing the generation of wind noise from the strut 220, the peak of the wind noise spectrum can be clarified. This makes it possible to accurately measure the dominant frequency of wind noise. As a result, it is possible to suppress a decrease in wind speed measurement accuracy caused by wind noise from the support 220 as noise.

(4-2) Modification 2 of one embodiment
Modification 2 of the present embodiment will be described with reference to FIG. 4B. FIG. 4B is a perspective view showing a pillar according to Modification 2 of the present embodiment.

As shown in FIG. 4B, in the anemometer 10 of Modification 2 of the present embodiment, the configuration of the strut 220 is different from that of the above-described embodiment and Modification 1. As shown in FIG.

In this modified example, each of the pair of struts 220 has, for example, unevenness on the outer periphery that suppresses the generation of Karman vortices more than a cylinder. In this modified example, each of the pair of struts 220 has, for example, a convex portion 222 spirally provided on the outer periphery. The convex portion 222 is provided by, for example, winding a linear body around the outer periphery of the columnar support 220 . The irregularities on the outer periphery of the support 220 may be provided by processing the outer periphery of the support 220 .

According to this modified example, by providing unevenness on the outer periphery of the support 220, the airflow can be disturbed by the unevenness in the vicinity of the outer periphery of the support 220. FIG. By generating turbulence in the airflow, it is possible to suppress the generation of Karman vortices near the support 220 and the generation of wind noise from the support 220 . The effect of suppressing the generation of wind noise from the strut 220 is the same as the effect of Modification 1 described above.

<Other embodiments of the present invention>
Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

Although the pair of struts 220 are separated in the above-described embodiment, the pair of struts 220 may be configured (connected) in a C-shape, for example.

In the above-described embodiment, the pair of struts 220 are provided vertically to support the sensor 100 in the horizontal direction. It may be supported along the vertical direction.

In the above-described embodiment, the frequency analysis unit 420, the wind speed calculation unit 430, and the recording unit 440 are separately provided. may be configured as one general-purpose computer.

In this case, the computer has, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a storage device as the recording unit 440, and an I/O port. A RAM, a storage device, and an I/O port are configured to be able to exchange data with the CPU. For example, an AD conversion unit 410 is connected to the I/O port. The storage device is designed to readably store the various data and programs described above. The RAM is configured to temporarily hold various data, programs, and the like read from the storage device by the CPU. The CPU is configured to function as the frequency analysis section 420 and the wind speed calculation section 430 by executing a predetermined program stored in the storage device. The predetermined program described above is used by being installed in a storage device, but it may be stored in a computer-readable storage medium and provided prior to the installation, or may be transmitted and received as described later. It may be provided to the computer via the unit.

In the above-described embodiment, the case where the anemometer 10 has the frequency analysis unit 420, the wind speed calculation unit 430, and the recording unit 440 has been described. At least one of the analysis unit 420, the wind speed calculation unit 430, and the reception unit that receives signals for controlling the recording unit 440 may be further provided.

In the modification 2 of the above-described embodiment, a case has been described in which the projections 222 are provided by winding a linear body around the outer periphery of the columnar support 220, but the unevenness is provided on the outer periphery of the prismatic support 220. may have been

<Preferred embodiment of the present invention>
Preferred embodiments of the present invention are described below.

(Appendix 1)
a columnar sensor having a predetermined Strouhal number;
a support that supports the sensor;
a sound collecting unit that collects wind noise from the sensor;
a frequency analysis unit configured to frequency-analyze the wind noise collected by the sound collection unit and acquire a wind sound spectrum;
a wind speed calculation unit that calculates a wind speed based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number;
has
The anemometer, wherein the support section has a pair of struts supporting both ends of the sensor.

(Appendix 2)
The anemometer according to appendix 1, wherein each of the pair of struts is thicker than the sensor.

(Appendix 3)
2. The anemometer according to appendix 1 or appendix 2, wherein each of the pair of struts has a prism shape.

(Appendix 4)
3. The anemometer according to any one of appendices 1 to 3, wherein each of the pair of struts has unevenness on an outer circumference that suppresses the generation of Karman vortices more than the column.

(Appendix 5)
5. The anemometer according to appendix 4, wherein each of the pair of struts has a convex portion spirally provided on an outer circumference thereof.

(Appendix 6)
The sound collecting unit has directivity,
6. The anemometer according to any one of appendices 1 to 5, wherein the direction in which the directivity of the sound collector is relatively high is directed toward the sensor.

(Appendix 7)
7. The anemometer according to any one of appendices 1 to 6, wherein the sensor is cylindrical.

(Appendix 8)
8. The anemometer according to any one of appendices 1 to 7, further comprising a rotation holding portion that holds at least the support portion rotatably in the horizontal direction so that the center axis of the sensor approaches perpendicular to the wind direction.

(Appendix 9)
The rotary holding portion holds the sound collecting portion rotatably in the horizontal direction together with the support portion so that the sensitivity of the sound collecting portion to collect wind noise from the sensor increases according to the direction of the wind. 9. An anemometer according to any one of appendices 1 to 8.

(Appendix 10)
The anemometer according to any one of appendices 1 to 9, wherein the sensor has an axial length of 700 mm or more.

(Appendix 11)
11. The anemometer according to any one of appendices 1 to 10, wherein the sensor has a thickness of 5 mm or more and 20 mm or less.

(Appendix 12)
a step of collecting wind noise from a columnar sensor having a predetermined Strouhal number;
a step of frequency-analyzing the collected wind noise to obtain a wind noise spectrum;
calculating a wind speed based on the dominant frequency of the dominant peak in the wind sound spectrum and the Strouhal number;
has
In the step of collecting wind noise,
A wind speed measurement method for collecting the wind noise while supporting both ends of the sensor.

10 Anemometer 100 Sensor 200 Supporting Part 220 Strut 222 Projecting Part 240 Connecting Part 300 Sound Collecting Part 410 AD Converting Part 420 Frequency Analysis Part 430 Wind Speed Calculating Part 440 Recording Part 450 Display Part 500 Rotation Holding Part 510 Rotating Shaft 520 Potentiometer 530 Holding Stand 540 wings

Claims (13)

a columnar sensor having a predetermined Strouhal number;
a support that supports the sensor;
a sound collecting unit that collects wind noise from the sensor;
a frequency analysis unit configured to frequency-analyze the wind noise collected by the sound collection unit and obtain a wind sound spectrum;
a wind speed calculation unit that calculates a wind speed based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number;
has
The support section has a pair of pillars that support both ends of the sensor,
Each of the pair of struts is thicker than the sensor
Anemometer. 2. The anemometer according to claim 1 , wherein each of said pair of struts has a prism shape. a columnar sensor having a predetermined Strouhal number;
a support that supports the sensor;
a sound collecting unit that collects wind noise from the sensor;
a frequency analysis unit configured to frequency-analyze the wind noise collected by the sound collection unit and obtain a wind sound spectrum;
a wind speed calculation unit that calculates a wind speed based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number;
has
The support section has a pair of pillars that support both ends of the sensor,
Each of the pair of pillars is configured in a prism shape.
Anemometer. 4. The anemometer according to any one of claims 1 to 3, wherein each of the pair of pillars has irregularities on the outer periphery that suppress the generation of Karman vortices more than the column. a columnar sensor having a predetermined Strouhal number;
a support that supports the sensor;
a sound collecting unit that collects wind noise from the sensor;
a frequency analysis unit configured to frequency-analyze the wind noise collected by the sound collection unit and acquire a wind sound spectrum;
a wind speed calculation unit that calculates a wind speed based on the dominant frequency of the prominent peak in the wind sound spectrum and the Strouhal number;
has
The support section has a pair of pillars that support both ends of the sensor,
Each of the pair of pillars has irregularities on its outer periphery that suppress the generation of Karman vortices more than the cylinder.
Anemometer. The sound collecting unit has directivity,
The anemometer according to any one of claims 1 to 5 , wherein the direction in which the directivity of the sound collector is relatively high is directed toward the sensor. The anemometer according to any one of claims 1 to 6 , wherein the sensor is configured in a columnar shape. The wind speed according to any one of claims 1 to 7 , further comprising a rotation holding portion that holds at least the support portion rotatably in the horizontal direction so that the center axis of the sensor approaches perpendicular to the wind direction. Total. The anemometer according to any one of claims 1 to 8 , wherein the sensor has an axial length of 700 mm or more. The anemometer according to any one of claims 1 to 9 , wherein the sensor has a thickness of 5 mm or more and 20 mm or less. a step of collecting wind noise from a columnar sensor having a predetermined Strouhal number;
a step of frequency-analyzing the collected wind noise to obtain a wind noise spectrum;
calculating a wind speed based on the dominant frequency of the dominant peak in the wind sound spectrum and the Strouhal number;
has
In the step of collecting wind noise,
A wind speed measuring method for collecting the wind noise while supporting both ends of the sensor by a pair of struts thicker than the sensor . a step of collecting wind noise from a columnar sensor having a predetermined Strouhal number;
a step of frequency-analyzing the collected wind noise to obtain a wind noise spectrum;
calculating a wind speed based on the dominant frequency of the dominant peak in the wind sound spectrum and the Strouhal number;
has
In the step of collecting wind noise,
The wind noise is collected in a state in which both ends of the sensor are supported by a pair of prismatic posts.
Wind speed measurement method. a step of collecting wind noise from a columnar sensor having a predetermined Strouhal number;
a step of frequency-analyzing the collected wind noise to acquire a wind noise spectrum;
calculating a wind speed based on the dominant frequency of the dominant peak in the wind sound spectrum and the Strouhal number;
has
In the step of collecting wind noise,
The wind noise is collected while both ends of the sensor are supported by a pair of struts having unevenness on the outer periphery that suppresses the generation of Karman vortices more than a cylinder.
Wind speed measurement method.

Images