Wave measurement method

Abstract

The invention discloses a wave measurement method, and belongs to the field of ocean observation. The wave measurement method comprises the following steps that a, a wave measurement device is installed at a measurement position, the wave measurement device comprises a radar water level gauge, a shaft and a floater sliding block, and the floater sliding block is arranged in the shaft; the radar water level gauge is mounted at the top end of the shaft; b, turning on a radar water level gauge; c, measuring the water level height and time when the velocity in the vertical direction of the wave is 0; d, recording three adjacent groups of data meeting the conditions in the step c; and e, calculating the wave period and the wave height. According to the Doppler principle, the radar type water level gauge and the like are adopted in a matched mode, and the characteristic that echo waves can generate frequency deviation when radar waves meet a radial moving target is utilized, so that the waves are measured simply, rapidly and accurately. And meanwhile, a floater sliding block and the like are arranged in the shaft, so that interference of waves and bubbles on radar echoes is further reduced, and the accuracy of measured data is improved.

Description

Technical Field

[0001] The invention relates to the field of ocean observation, and in particular to a wave measurement method. Background Art

[0002] Wave measurement can help monitor and predict changes in wave parameters at sea, which is very important for improving the disaster prevention capabilities of ports. Through wave measurement, sea conditions can be effectively forecasted, the losses of coastal ports under extreme disaster conditions can be reduced, and the safety of port and wharf production operations and people's lives and property can be guaranteed. At the same time, wave measurement has a wide range of applications in wave power generation, marine engineering design and construction, marine environment monitoring and disaster warning, scientific research and climate change research.

[0003] The main wave measurement methods include optical wave meter wave measurement, measuring rod wave measurement, pressure wave measurement and acoustic wave measurement. The optical wave meter wave measurement method uses the correlation between the underwater emission light field and the sea surface wave height to measure the physical parameters of the wave. The measuring rod wave measurement method is to use a wave measuring pole fixed vertically in the sea with the help of piles, brackets or neutral buoys. The above two wave measurement methods have low accuracy, are greatly affected by subjective factors, and are not convenient for measurement at night. The pressure wave measurement method measures the change of seawater pressure through a pressure sensor placed underwater or on the seabed, and then converts it into wave height; according to the linear wave theory, the relationship between the wave surface and the wave pressure can be obtained. This method is suitable for long-term fixed-point continuous observation, but it is affected by the filtering effect of seawater and cannot accurately measure short-term waves. The acoustic wave measurement method uses an acoustic transducer placed on the seabed to emit sound pulses vertically to the sea surface, measures the change of the vertical distance from the transducer to the sea surface by receiving the echo signal, and then converts it into wave height. This method can avoid the damage caused by strong winds and waves on the sea surface, but the accuracy of measuring breaking waves is affected by interference from waves and bubbles.

[0004] In summary, most of the existing wave measurement methods have problems such as complex measurement equipment structure, cumbersome installation, too much data to be measured, and complex calculation process.

[0005] Therefore, it is necessary to propose a wave measurement method to solve the above technical problems existing in the prior art. Summary of the invention

[0006] The object of the present invention is to provide a wave measurement method to achieve simple, rapid and accurate wave measurement.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A wave measurement method, which uses a wave measurement device, the wave measurement device includes a radar water level gauge, a wellbore and a float slider, the float slider is arranged in the wellbore, and the float slider can follow the rise and fall of the water level; the radar water level gauge is installed at the top of the wellbore;

[0009] The method comprises the following steps:

[0010] a. Install the wave measuring device at the measuring position, with the wellbore arranged vertically and the lower part of the wellbore in the seawater;

[0011] b. Turn on the radar water level gauge in the wave measuring device;

[0012] c. Measure the water level and time when the vertical velocity of the wave is 0;

[0013] d. Record three adjacent sets of data that meet the conditions in step c;

[0014] e. Calculate the wave period and wave height.

[0015] In the above step c: the calculation formula of the water level is as follows: ;

[0016] In the formula, is the actual water level, The water level measured by the radar level gauge. It is the height difference between the upper surface of the float slider and the water surface.

[0017] In the above step d: the data includes three adjacent time points when the vertical velocity of the wave is 0 , and , and in , and The actual water level at the moment , and ;

[0018] According to the Doppler principle, when the radar wave encounters a radially moving target, the echo will have a frequency shift, so the formula is as follows:

[0019] (1)

[0020] (2)

[0021] In formula (1) and formula (2), is the initial frequency of the radar wave, is the echo frequency of the radar wave, is the frequency change value of the radar wave, V is the vertical velocity of the wave, and C is the electromagnetic wave transmission velocity of the radar water level gauge;

[0022] According to the above formula, the formula is as follows:

[0023] (3)

[0024] Then obtain the vertical speed of the wave ;

[0025] When the vertical speed of the wave When the wave is at the crest or trough, The time difference between two adjacent peaks or troughs, that is, the calculation formula of the wave period is:

[0026] (4)

[0027] In formula (4), is the wave period, and It is the time when two adjacent peaks or troughs appear; for and The time when a trough or peak occurs between moments;

[0028] The wave height is calculated as follows:

[0029] (5)

[0030] In the formula, is the height of the wave, for The water level at the moment, for The water level at the moment; for The water level at the moment.

[0031] Preferably, the float slider is cylindrical.

[0032] Preferably, the diameter of the float slider is 0.8 to 0.9 times the inner diameter of the wellbore.

[0033] Preferably, the upper surface of the float slider remains parallel to the water surface.

[0034] Preferably, the side wall of the wellbore is provided with a plurality of water inlet and outlet holes which penetrate inside and outside.

[0035] Preferably, the water inlet and outlet holes are square or elongated.

[0036] Preferably, the wave measuring device is used on an offshore platform.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The wave measurement method of the present invention is based on the Doppler principle, and is used in conjunction with a radar water level meter. The characteristic that the echo will have a frequency shift when the radar wave encounters a radial moving target is utilized, and the water level height and multiple sets of time-adjacent data when the vertical velocity of the wave is 0 are measured, thereby achieving simple, fast and accurate measurement of the wave. At the same time, the wave measurement device adopted by the present invention is provided with a float slider in the wellbore, and the float slider can rise and fall with the water level, and the upper surface of the float slider is always kept parallel to the water surface, thereby reducing the interference of waves and bubbles on the radar echo, and improving the accuracy of the measurement data.

[0039] The wave measuring device used in the present invention has a simple design structure, is easy to install, and the measurement is not affected by natural factors such as weather. At the same time, the present invention only needs to measure two data, time and water level height, and the data processing process is simple, which greatly reduces the cost of wave measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0041] Figure 1 It is a schematic diagram of the flow of the wave measurement method of the present invention;

[0042] Figure 2 A schematic diagram of the structural principle of the wave measuring device used in the present invention;

[0043] Figure 3 for Figure 2 A schematic structural diagram of an implementation method of a wellbore;

[0044] Figure 4 for Figure 2 A schematic structural diagram of another embodiment of the middle wellbore.

[0045] In the figure: 1- radar probe, 2- wellbore, 3- float slider, 4- water surface, 5- water inlet and outlet holes. DETAILED DESCRIPTION

[0046] like Figure 1 As shown, a wave measurement method, the method uses a wave measurement device, such as Figure 2-Figure 4As shown, the wave measuring device includes a radar water level gauge, a wellbore 2 and a float slider 3. The float slider 3 is arranged in the wellbore 2. The float slider 3 can rise and fall with the water level. The float slider 3 can be arranged in a cylindrical shape. The radar water level gauge is installed at the top of the wellbore 2. The wellbore 2 is cylindrical in shape. The side wall of the wellbore 2 is provided with a plurality of water inlet and outlet holes 5 that are connected inside and outside. At the same time, the diameter of the float slider 3 is slightly smaller than the inner diameter of the wellbore 2, which can not only make the float slider 3 rise and fall with the water level in the wellbore 2, but also ensure that the upper surface of the float slider 3 remains parallel to the water surface 4 when the float slider 3 rises and falls with the water level.

[0047] A radar water level meter is installed at the top of the wellbore 2 , and a radar probe 1 of the radar water level meter is arranged inside the wellbore 2 .

[0048] The radar probe 1 emits a vertically downward pulse radar wave. The radar wave propagates in the air. When the radar wave encounters the water surface 4, it will be reflected back. The distance from the radar probe 1 to the water surface 4 is judged according to the echo time, thereby determining the water level.

[0049] According to the Doppler principle, the echo of radar waves will have a frequency shift when encountering a radially moving target. Therefore, when the vertical velocity v of the wave is much smaller than the electromagnetic wave propagation velocity (pulse radar wave) of the radar water level meter or the speed of light C, the formula is as follows:

[0050] (1)

[0051] (2)

[0052] In formula (1) and formula (2), is the initial frequency of the radar wave, is the echo frequency of the radar wave, is the frequency change value of the radar wave, V is the vertical velocity of the wave, and C is the electromagnetic wave transmission speed of the radar water level meter.

[0053] When the water surface 4 moves upward toward the radar, is a positive value; when the water surface 4 moves downward away from the radar, Is a negative value.

[0054] According to formula (1), the formula is as follows:

[0055] (3)

[0056] Then obtain the vertical speed of the wave .

[0057] When the wave is at the crest or trough, the vertical speed of the wave is , that is, in each At the moment, the wave is at a peak or a trough. , and The moments are adjacent Moment (i.e. ),but It is the time difference between two adjacent wave peaks or two adjacent wave troughs, that is, the wave period is:

[0058] (4)

[0059] In formula (4), is the wave period, is the time when the peak or trough occurs, For The times when peaks or troughs occur at adjacent moments at the same time.

[0060] At the same time, and Measure the water level at all times and , and is the water level between two adjacent wave crests or troughs, then the wave height for:

[0061] (5)

[0062] In the formula, is the height of the wave, is the water level height at the crest or trough, For the height of the water level in adjacent troughs or crests; For The height of adjacent water levels that are synchronously at the crest or trough of a wave.

[0063] According to the above principle, this embodiment provides a wave measurement method, using the above wave measurement device, the wave measurement method includes the following steps:

[0064] a. Install the wellbore 2, the float slider 3 and the radar water level gauge on the offshore platform.

[0065] b. Turn on the radar water level gauge.

[0066] c. Measure the water level and time when the vertical velocity of the wave is 0. The water level is calculated as follows: .

[0067] In the formula, is the actual water level, The water level measured by the radar level gauge. is the height difference between the upper surface of the float slider 3 and the water surface 4.

[0068] d. Record three sets of data that meet the conditions in step c, where the data includes three adjacent time points when the vertical velocity of the wave is 0. , and , and in , and The actual water level at the moment , and .

[0069] e. Calculate the wave period and wave height, where the wave period is calculated as follows: .

[0070] In the formula, is the wave period, is the time when the peak (trough) appears, For The time when the peaks (troughs) of waves appear synchronously at adjacent moments.

[0071] The wave height is calculated as follows: .

[0072] In the formula, is the height of the wave, is the water level height of the crest (trough), For The water level height of the adjacent trough (peak); For The water level height of adjacent crests (troughs).

[0073] This embodiment uses the Doppler principle and the characteristic that the echo will have a frequency shift when the radar wave encounters a radial moving target, thereby realizing simple, fast and accurate measurement of waves. At the same time, the present invention adopts a wave measurement device, by arranging a float slider 3 in the wellbore 2, the float slider 3 can rise and fall with the water level, and the upper surface of the float slider 3 is always kept parallel to the water surface 4, thereby reducing the interference of waves and bubbles on the radar echo and improving the accuracy of the measurement data.

[0074] The wave measurement device in this embodiment has a simple design structure, is easy to install, and the measurement is not affected by natural factors such as weather. At the same time, the present invention only needs to measure two data, time and water level height, and the data processing process is simple, which greatly reduces the cost of wave measurement.

[0075] The wave measuring device is further described below in conjunction with the accompanying drawings:

[0076] like Figures 2 to 4 As shown, the wave measuring device is installed on an offshore platform, the wellbore 2 is arranged vertically, and the lower part of the wellbore 2 is placed below the water surface, which can be set open. The float slider 3 is arranged in the wellbore 2, and the diameter of the float slider 3 is 0.9 times the inner diameter of the wellbore 2, which not only ensures that the float slider 3 can rise and fall with the water surface 4, but also prevents the float slider 3 from tipping over and affecting the measurement accuracy. The radar water level gauge is arranged at the top of the wellbore 2, and the radar probe 1 extends inside the wellbore 2. A plurality of long strip-shaped inlet and outlet holes 5 are opened on the side wall of the wellbore 2 of the wave measuring device. The inlet and outlet holes 5 are arranged in two rows, and the inlet and outlet holes 5 penetrate the side wall of the wellbore 2. The inlet and outlet holes 5 can keep the water level inside the wellbore 2 the same as the water level outside the wellbore 2 at all times, which is convenient for the exchange of seawater inside and outside the wellbore, will not affect the waves on the sea surface, and ensures the measurement accuracy.

[0077] Of course, the diameter of the float slider 3 is not limited to 0.9 times the inner diameter of the wellbore 2, and the shape of the water inlet and outlet holes 5 is not limited to the long strip shape, and can be reasonably changed according to actual conditions.

[0078] The embodiments of the present invention are only used to illustrate the technical solutions of the present invention rather than to limit the present invention. It can be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A wave measurement method, characterized in that: A wave measuring device is used, which includes a radar water level gauge, a wellbore and a float slider, wherein the float slider is arranged in the wellbore and can rise and fall with the water level; the radar water level gauge is installed at the top of the wellbore; The method comprises the following steps: a. Install the wave measuring device at the measuring position, with the wellbore arranged vertically and the lower part of the wellbore in the seawater; b. Turn on the radar water level gauge in the wave measuring device; c. Measure the water level and time when the vertical velocity of the wave is 0; d. Record three adjacent sets of data that meet the conditions in step c; e. Calculate the wave period and wave height.

2. A wave measurement method according to claim 1, characterized in that: In step c: the calculation formula for the water level is as follows: ; In the formula, is the actual water level, The water level measured by the radar level gauge. It is the height difference between the upper surface of the float slider and the water surface.

3. A wave measurement method according to claim 1, characterized in that: In step d: the three adjacent sets of data include the three adjacent moments when the vertical velocity of the wave is 0 , and , and in , and The actual water level at the moment , and ; According to the Doppler principle, when the radar wave encounters a radially moving target, the echo will have a frequency shift, so the formula is as follows: （1） （2） In formula (1) and formula (2), is the initial frequency of the radar wave, is the echo frequency of the radar wave, is the frequency change value of the radar wave, V is the vertical velocity of the wave, and C is the electromagnetic wave transmission velocity of the radar water level gauge; According to the above formula, the formula is as follows: （3） Then obtain the vertical speed of the wave ; When the vertical speed of the wave When the wave is at the crest or trough, The time difference between two adjacent peaks or troughs, that is, the calculation formula of the wave period is: （4） In formula (4), is the wave period, and It is the time when two adjacent peaks or troughs appear; for and The time when a trough or peak occurs between moments; The wave height is calculated as follows: （5） In the formula, is the height of the wave, for The water level at the moment, for The water level at the moment; for The water level at the moment.

4. A wave measurement method according to claim 1, characterized in that: The float slider is cylindrical.

5. A wave measurement method according to claim 4, characterized in that: The diameter of the float slider is 0.8 to 0.9 times the inner diameter of the wellbore.

6. A wave measurement method according to claim 4, characterized in that: The upper surface of the float slider is kept parallel to the water surface.

7. A wave measurement method according to claim 1, characterized in that: The side wall of the wellbore is provided with a plurality of water inlet and outlet holes which are connected inside and outside.

8. A wave measurement method according to claim 7, characterized in that: The water inlet and outlet holes are in a square or long strip shape.

9. A wave measurement method according to claim 1, characterized in that: The wave measuring device is used on an offshore platform.

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