CN116194731A - Wave measuring device - Google Patents
Wave measuring device Download PDFInfo
- Publication number
- CN116194731A CN116194731A CN202180061414.3A CN202180061414A CN116194731A CN 116194731 A CN116194731 A CN 116194731A CN 202180061414 A CN202180061414 A CN 202180061414A CN 116194731 A CN116194731 A CN 116194731A
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- Prior art keywords
- wave
- draft
- sway
- data
- water level
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C13/00—Surveying specially adapted to open water, e.g. sea, lake, river or canal
- G01C13/002—Measuring the movement of open water
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B79/00—Monitoring properties or operating parameters of vessels in operation
- B63B79/10—Monitoring properties or operating parameters of vessels in operation using sensors, e.g. pressure sensors, strain gauges or accelerometers
- B63B79/15—Monitoring properties or operating parameters of vessels in operation using sensors, e.g. pressure sensors, strain gauges or accelerometers for monitoring environmental variables, e.g. wave height or weather data
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C13/00—Surveying specially adapted to open water, e.g. sea, lake, river or canal
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Hydrology & Water Resources (AREA)
- Atmospheric Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
A wave measuring device is provided with: a plurality of draft meters (11-14) which are respectively arranged at a plurality of different positions of the water moving body and measure draft; a sway meter (15) for measuring sway of the water-borne moving body; and a wave measurement unit (2) that calculates time-series data of absolute water level fluctuations at a plurality of positions based on draft data measured by the plurality of draft meters (11-14) and sway data measured by the sway meter (15), performs cross-spectrum analysis based on the time-series data of absolute water level fluctuations at the plurality of positions, and measures wave information including at least one of wave height, wave direction, and period based on an analysis result from the cross-spectrum analysis.
Description
Technical Field
The present invention relates to a wave measuring device for measuring waves.
Background
In general, it is desirable to measure waves while a ship is underway (see non-patent document 1).
However, in sailing, it is not easy to measure waves due to the inclination of the hull or the like, and it is difficult to obtain measurement accuracy.
Prior art literature
Non-patent literature
Non-patent document 1: gao Dan and others, "research on development of ship-borne wave information prompt System", japanese society of shipbuilding, 2002, no. 192, p.171-180
Disclosure of Invention
An object of an embodiment of the present invention is to provide a wave measuring device for easily measuring waves in sailing of a water moving body.
According to an aspect of the present invention, a wave measurement device includes: a plurality of draft measuring units which are respectively provided at a plurality of positions of the water moving body, which are different from each other, and measure draft; a sway measuring unit that measures sway of the water-borne moving body; an absolute water level fluctuation calculation unit that calculates time-series data of absolute water level fluctuation at the plurality of positions based on the draft data measured by the plurality of draft measurement units and the sway data measured by the sway measurement unit; a cross spectrum analysis unit that performs cross spectrum analysis based on time-series data of the absolute water level fluctuation of the plurality of positions; and a wave measuring unit that measures wave information including at least one of wave height, wave direction, or period based on an analysis result according to the cross spectrum analysis unit.
Drawings
Fig. 1 is a structural view showing the structure of a wave measuring device according to an embodiment of the present invention.
Fig. 2 is a schematic view of a ship showing a mounted state of a measuring instrument according to the present embodiment.
Fig. 3 is a flowchart showing steps of a wave measuring method according to the wave measuring section according to the present embodiment.
Fig. 4 is a waveform diagram showing measurement data according to the measuring instrument class according to the present embodiment.
Fig. 5 is a waveform diagram showing up-down acceleration data according to the present embodiment.
Fig. 6 is a waveform diagram showing up-down displacement data according to the present embodiment.
Fig. 7 is a waveform diagram showing absolute water level fluctuation data according to the present embodiment.
Fig. 8 is a waveform diagram showing spectrum analysis data according to the present embodiment.
Detailed Description
(embodiment)
Fig. 1 is a structural view showing the structure of a wave measuring device 1 according to an embodiment of the present invention. Fig. 2 is a schematic view of the ship 10 showing the mounted state of the measuring instruments 11 to 15 according to the present embodiment. The same reference numerals are given to the same parts in the drawings, and duplicate descriptions are omitted as appropriate.
The wave measuring device 1 is arranged on a ship 10 and is constituted by a computer. The ship 10 may be any water-borne moving body that moves on water. For example, it may be a facility or an artificial island that does not have movement as a primary purpose. Here, the water-borne moving body will be mainly described as a ship.
The wave measuring device 1 includes four draft meters 11, 12, 13, 14, a sway meter 15, a wave measuring unit 2, and a display 3. The equipment constituting the wave measuring device 1 may be used as ship equipment or the like provided independently of the wave measuring device 1, or may be off-board equipment or facilities such as GPS (global positioning system).
Here, the configuration using four draft meters 11 to 14 is described, but any number of draft meters 11 to 14 may be used as long as it is four or more. The arrangement of the draft meters 11 to 14 is not limited to the positions described herein, and may be arbitrarily arranged as long as draft data of the draft meters 11 to 14 are different from each other.
A sway gauge 15 is mounted on the vessel 10. The sway meter 15 measures forward/backward sway (heave), side-to-side sway (heave), up/down sway (heave), lateral sway (roll), longitudinal sway (pitch), and bow sway (yaw). The sway meter 15 transmits data (sway data) related to the measured sway to the wave measurement unit 2. For example, the rocking data are acceleration, angular velocity, and tilt angle.
The rocking meter 15 may be used for measuring in any manner, or may be constituted by a plurality of devices. The yaw meter 15 may measure lateral yaw, longitudinal yaw, and vertical acceleration, and may not measure other yaw. The sway meter 15 may be used for a measurement other than the purpose of use in the wave measuring device 1. For example, the data measured by the sway gauge 15 may be used for the purpose of monitoring or controlling the attitude of the vessel 10.
The wave measuring unit 2 obtains (measures) information (wave information) related to the waves based on the draft data received from each of the draft meters 11 to 14 at each installation position and the sway data received from the sway meter 15. For example, wave information is wave height, wave direction, and period. The wave measuring part 2 converts the measured wave information into information for display on the display 3 and transmits the information to the display 3. If the wave information includes at least one of wave height, wave direction, and period, other elements may not be operated or displayed.
The display 3 displays wave information received from the wave measuring part 2. An operator such as a crew member can grasp the wave information by looking at the display 3. It should be noted that the display 3 may be provided outside the ship 10. Thus, even an overboard person can grasp wave information. For example, the measured data on each vessel 10 traveling on the world's main course may be aggregated and analyzed to produce a map showing worldwide wave information.
Fig. 3 is a flowchart showing steps of a wave measuring method according to the wave measuring part 2 according to the present embodiment.
The wave measuring unit 2 calculates a relative water level fluctuation by dividing the draft data of each installation position measured by the draft meters 11 to 14 by the average draft (step ST 1).
The wave measuring unit 2 calculates an absolute water level fluctuation by correcting the calculated relative water level fluctuation based on the sway data measured by the sway measuring meter 15 (step ST 2).
Specifically, a method of calculating the absolute water level will be described.
The vertical acceleration of the installation position of the draft meters 11 to 14 is calculated based on the yaw rate, the pitch rate, and the vertical acceleration of the installation position of the yaw meter 15. The vertical acceleration of the installation position of each of the draft meters 11 to 14 is obtained by the following equation using the vertical acceleration of the installation position of the yaw meter 15, the angular acceleration of the longitudinal yaw angle, and the angular acceleration of the lateral yaw angle.
[ mathematics 1]
Wherein, the liquid crystal display device comprises a liquid crystal display device,
is the up-down acceleration of the setting position of the draft meter,/->
Is the up-down acceleration of the setting position of the swing gauge, +.>
Angular acceleration, which is the longitudinal swing angle, +.>
Angular acceleration, x, being the yaw angle p ，y p Is the coordinates of the set position of the draft meter, x 0 ，y 0 Is the coordinates of the set position of the rocking meter.
The vertical displacement is obtained by integrating the vertical acceleration 2 times by the integration method using an infinite impulse response (IIR, infinite Impulse Response) digital filter using the following equation.
[ math figure 2]
Where x (n) is the up-down displacement, n is time, Δ is the time interval, λ is the time constant of the filter.
Thus, the absolute water level fluctuation of the installation positions of the draft meters 11 to 14 is obtained by subtracting the vertical displacement from the relative water level fluctuation.
The wave measuring unit 2 performs cross spectrum analysis on time-series data of the absolute water level fluctuation based on the absolute water level fluctuation of the installation positions of the four draft meters 11 to 14 (step ST 3). For example, the wave measuring unit 2 performs data analysis with the absolute water level as a single amplitude, and multiplies the result of the frequency (spectrum) analysis by 2 times, thereby converting the result into an absolute wave height as a double amplitude. The wave measuring unit 2 may perform data analysis with an absolute wave height.
Based on the analysis result, the wave measurement unit 2 calculates the wave height, wave direction, and period as wave information (step ST 4).
Next, a method of obtaining wave information based on the absolute water levels of the installation positions of the draft meters 11 to 14 based on the measurement results of the draft meters 11 to 14 and the sway meter 15 will be described.
Here, cross spectrum analysis is performed on time-series data of absolute water level fluctuation using a multidimensional autoregressive model, which is one of statistical time-series models. Thereby, information related to the amplitude/phase characteristics (cross spectrum) between the variables is estimated. The variable refers to the absolute water level estimated at the installation positions of the four draft meters 11 to 14.
The cross spectrum is composed of a self-component (self-power spectrum) indicating a relationship between itself and a cross component (cross spectrum) indicating a relationship between itself and another variable. The cross spectrum becomes complex. The self-component of the spectrum is a real number representing the power (square of amplitude) at that frequency, with the imaginary part being 0. Thus, this represents the amplitude characteristics of the variable of interest itself. On the other hand, the cross-component of the spectrum represents the strength of the correlation between the variables at that frequency. By complex, it is meant that a vector is written on the complex plane so that the angle, i.e. the phase, with the real axis can be known. Thus, the cross-component represents the phase relationship between the variables of interest.
Wave height, wave direction and wave period are estimated as follows. Here, the cross spectrum analysis uses a multivariate autoregressive model analysis method.
The cross spectrum of the absolute water level between two points of the measurement position is obtained by the following equation using a cross correlation function.
[ math 3]
Where i, j is the absolute water level measurement position, s i，j And (ω) is the cross-spectrum of the absolute water level between these two points.
[ mathematics 4]
s i，j (ω) =co (ω) + iQu (ω) formula (6)
Wherein Co (ω) is a Co-spectrum, qu (ω) is an orthogonal spectrum,
using these, the phase difference of the absolute water level between the two points is obtained by the following equation.
[ math 5]
Wherein ε i，j And (ω) is the phase difference between the two points.
The wave direction is determined by the following equation using the phase difference at the dominant frequency of the sum of the power spectra of the absolute water levels at three points.
[ math figure 6]
Wherein χ is wave direction, ω p Is three points (P) 0 ，P 1 ，P 2 ) The principal frequency of the sum of the absolute water level power spectra, ε i，j (ω p ) Is the phase difference at the main frequency, r 1 Is P 0 And P 1 Distance between r 2 Is P 0 And P 1 Distance between them.
The representative period is obtained by the following equation. Regarding the sense wave height, the power spectrum of the absolute water level at three points is averaged and the square root thereof is multiplied by 4 times to obtain.
[ math 7]
Where T is the representative period.
The frequency analysis is not limited to that described herein. The Fast Fourier Transform (FFT) method, the Blackman-Du Kai (Blackman-Tukey) method using a correlation function, and the berg (Burg) maximum entropy method may be used. Here, in the method using the correlation function, the order of the model needs to be determined, but in the above method, the model order can be objectively determined on the basis of the information amount criterion.
With reference to fig. 4 to 8, the analysis is performed on the measurement data DG1 from the measuring instruments including the draft meters 11 to 14 and the sway meter 15 mounted on the ship 10 until wave information is obtained.
As shown in fig. 4, measurement data DG1 of the surveying instrument class according to the ship 10 is obtained. The horizontal axis of waveforms W11 to W19 is time (seconds). Waveform W11 represents heading (degrees), waveform W12 represents ground speed (knots), waveform W13 represents roll angular velocity (degrees/sec), waveform W14 represents pitch angular velocity (degrees/sec), waveform W15 represents up-down acceleration (m 2/sec), waveform W16 represents draft data (m) of draft meter 11 according to the bow, waveform W17 represents draft data (m) of draft meter 12 according to the central port, waveform W18 represents draft data (m) of draft meter 13 according to the central starboard, and waveform W19 represents draft data (m) of draft meter 14 according to the stern. It should be noted that the heading and the speed to ground are reference data, or may not be measured.
As shown in fig. 5, vertical acceleration data DG2 at the installation position of the draft meters 11 to 14 is obtained from the measurement data DG1. In the waveforms W21 to W24, the horizontal axis represents time (seconds), and the vertical axis represents acceleration (m≡2/second). Waveform W21 represents the acceleration data of the bow, waveform W22 represents the acceleration data of the central port, waveform W23 represents the acceleration data of the central starboard, and waveform W24 represents the acceleration data of the stern.
As shown in fig. 6, vertical displacement data DG3 is obtained from vertical acceleration data DG2. In waveforms W31 to W34, the horizontal axis represents time (seconds) and the vertical axis represents displacement (m). Waveform W31 represents the up-down displacement data of the bow, waveform W32 represents the up-down displacement data of the central port, waveform W33 represents the up-down displacement data of the central starboard, and waveform W34 represents the up-down displacement data of the stern.
As shown in fig. 7, absolute water level fluctuation data DG4 is obtained from the vertical displacement data DG3. In waveforms W41 to W44, the horizontal axis represents time (seconds) and the vertical axis represents water level (m). Waveform W41 represents the absolute water level fluctuation data of the bow, waveform W42 represents the absolute water level fluctuation data of the central port, waveform W43 represents the absolute water level fluctuation data of the central starboard, and waveform W44 represents the absolute water level fluctuation data of the stern.
As shown in fig. 8, spectrum analysis data DG5 is obtained from the absolute water level fluctuation data DG4. In the spectrum analysis data DG5, the installation positions of the draft meters 11 to 14 of one of the two waveform data are, in order from the top: the first row represents the bow, the second row represents the central port, the third row represents the central starboard, and the fourth row represents the stern; the other draft meters 11 to 14 are provided at the following positions in order from the left: the first column indicates the bow, the second column indicates the central port, the third column indicates the central starboard, and the fourth column indicates the stern. Therefore, the waveform located on the lower right diagonal line of the analysis data DG5 represents the self-power spectrum, and the other waveforms represent the cross spectrum.
In each waveform of the spectrum analysis data DG5, the horizontal axis represents frequency (Hz), the vertical axis represents spectral density (m 2 sec), the solid line represents the real part of the spectrum, and the broken line represents the imaginary part of the spectrum.
The wave information estimated from the spectrum analysis data DG5 is: the sense wave height was 0.66m, the wave direction (clockwise rotation from bow was positive) was 127.3 degrees, and the average wave period was 7.0 seconds.
According to the present embodiment, by performing cross spectrum analysis on time-series data of water level fluctuation based on measurement results from the draft meters 11 to 14 and the sway meter 15, wave information including wave height, wave direction, and period can be obtained. This enables the crew to grasp wave information while the ship 10 is underway.
Further, since the draft meters 11 to 14 and the sway meter 15 constituting the wave measuring device 1 can use conventional equipment, the cost of facilities of the ship 10 can be reduced by being used in combination with other applications than the wave measuring device 1. In addition, if the water moving body (ship) is provided with at least one of the draft meters 11 to 14 or the sway meter 15, the cost of modification of installing the wave measuring device 1 can be suppressed by using existing equipment.
The present invention is not limited to the above embodiment, and the constituent elements may be deleted, added, or changed. Further, a new embodiment may be obtained by combining or replacing the constituent elements of the plurality of embodiments. Even though such an embodiment is directly different from the above-described embodiment, the description of the same embodiment as the gist of the present invention is omitted because it has been described as an embodiment of the present invention.
Claims (3)
1. A wave measuring device is characterized by comprising:
a plurality of draft measuring units which are respectively provided at a plurality of positions of the water moving body, which are different from each other, and measure draft;
a sway measuring unit that measures sway of the water-borne moving body;
an absolute water level fluctuation calculation unit that calculates time-series data of absolute water level fluctuation at the plurality of positions based on the draft data measured by the plurality of draft measurement units and the sway data measured by the sway measurement unit;
a cross spectrum analysis unit that performs cross spectrum analysis based on time-series data of the absolute water level fluctuation of the plurality of positions;
and a wave measurement unit that measures wave information including at least one of wave height, wave direction, or period based on an analysis result according to the cross spectrum analysis unit.
2. The wave measurement device according to claim 1, wherein,
the plurality of positions are provided in the forward and backward directions in the propulsion direction and in the left and right directions perpendicular to the propulsion direction with respect to the center of the surface of the water surface moving body.
3. A method of wave measurement, comprising:
measuring draft at a plurality of positions of the aquatic moving body different from each other;
measuring the sway of the aquatic mobile body;
calculating time-series data of absolute water level fluctuation of the plurality of positions based on draft data measured at mutually different positions and measured sway data;
performing cross-spectrum analysis based on time-series data of the absolute water level variations of the plurality of locations;
wave information including at least one of wave height, wave direction or period is measured based on an analysis result according to the cross-spectrum analysis.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-120654 | 2020-07-14 | ||
| JP2020120654A JP2022017851A (en) | 2020-07-14 | 2020-07-14 | Wave measuring device |
| PCT/JP2021/026338 WO2022014602A1 (en) | 2020-07-14 | 2021-07-13 | Wave measuring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116194731A true CN116194731A (en) | 2023-05-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180061414.3A Pending CN116194731A (en) | 2020-07-14 | 2021-07-13 | Wave measuring device |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2022017851A (en) |
| KR (1) | KR20230021124A (en) |
| CN (1) | CN116194731A (en) |
| WO (1) | WO2022014602A1 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4892972B2 (en) * | 2005-11-24 | 2012-03-07 | 株式会社Ｊｖｃケンウッド | Wave height measuring device |
| JP5390453B2 (en) * | 2010-03-31 | 2014-01-15 | 三井造船株式会社 | Incidence wave height and wave direction estimation method, automatic channel or / and ship position maintaining control method, automatic channel or / and ship position maintaining control system, and ship and offshore structure |
| JP6867666B2 (en) * | 2015-07-10 | 2021-05-12 | 国立研究開発法人 海上・港湾・航空技術研究所 | Floating body with wave measuring device and wave measuring device |
| EP3379299A4 (en) * | 2015-11-20 | 2019-07-03 | Fluid Techno Co., Ltd. | Hydrographic phenomena estimation apparatus and hydrographic phenomena estimation method |
-
2020
- 2020-07-14 JP JP2020120654A patent/JP2022017851A/en active Pending
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2021
- 2021-07-13 KR KR1020237000716A patent/KR20230021124A/en unknown
- 2021-07-13 WO PCT/JP2021/026338 patent/WO2022014602A1/en active Application Filing
- 2021-07-13 CN CN202180061414.3A patent/CN116194731A/en active Pending
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| Publication number | Publication date |
|---|---|
| WO2022014602A1 (en) | 2022-01-20 |
| JP2022017851A (en) | 2022-01-26 |
| KR20230021124A (en) | 2023-02-13 |
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