CN113155408B - Wave maker experimental device and method based on point pressure feedback wave height display - Google Patents

Abstract

The invention belongs to the technical field of marine engineering, and relates to an experimental device and method for a wave maker based on point pressure feedback wave height display, wherein the experimental method includes the following steps: (1) setting a pressure sensor, (2) collecting pressure data, ( 3) Deriving the expression of wave pressure, (4) solving the unknown coefficient, (5) solving the change of wave height with time at the wave-making plate at time t. The wave-making machine experimental device of the present invention uses a pressure sensor to measure the pressure generated by the wave on the wave-making plate, and finds the relationship between the pressure and the wave height, thereby realizing the conversion between the pressure and the wave height, and avoiding the pressure caused by the wave-making The waves in front of the board are turbulent, and the wave height sequence values measured by the wave height sensor are very complex, and it is difficult to accurately separate real-time reflected waves. The whole experimental device is simple in structure, easy to operate, safe and reliable.

Description

A wave maker experimental device and method based on point pressure feedback wave height display

technical field

The invention relates to a wave maker experimental device based on point pressure feedback wave height display and a method thereof, belonging to the technical field of marine engineering.

Background technique

The wave physical model test is one of the main means to study the wave-proof performance of coastal port engineering. Currently, there are two ways for the tank to absorb reflected waves, namely passive absorption and active absorption.

The domestic active absorption wave-making system mainly uses the wave height sensor in front of the wave-making plate to measure the wave height sequence value, and then performs numerical filtering to separate the reflected wave and feed it back to the control system. The control system corrects the wave-making signal according to the feedback reflected wave signal to achieve secondary absorption. The purpose of the reflected wave. However, due to the turbulent waves in front of the wave-making plate, the wave-height sequence values measured by the wave-height sensor are very complicated, and it is difficult to accurately separate the real-time reflected waves. Moreover, for the rocking-plate wave-making machine, the location of the wave-making machine is also controversial, and this The error of this method is relatively large and unstable, and it is easy to cause the absorption effect of the secondary reflected wave of the wave maker to deteriorate.

Contents of the invention

In order to overcome the deficiencies in the prior art, the object of the present invention is to provide a wave maker experimental device and method based on point pressure feedback wave height display. The experimental device uses a pressure sensor to measure the pressure generated by the wave on the wave-making plate, and finds the relationship between the pressure and the wave height, so as to realize the conversion between the pressure and the wave height, and avoid the wave height caused by the wave disorder in front of the wave-making plate. The wave height sequence values measured by the sensor are very complex, and it is difficult to accurately separate real-time reflected waves.

In order to achieve the purpose of the above invention and solve the problems existing in the prior art, the technical solution adopted by the present invention is: a wave maker experimental device based on point pressure feedback wave height display, including a deep water pool, a computer control system, a dry back shaker Plate wave maker and N pressure sensors, computer control system, including AC servo motor, computer control unit and wave height change display unit, the dry-back rocking plate wave maker is equipped with a wave plate, a transmission rod, a first , 2 bearings, sliders, screw rods and shaft couplings, the wave-making plate is connected to the transmission rod, the transmission rod is connected to the slider, the slider is inserted into the screw rod, and the two ends of the screw rod are respectively provided with first and second bearing, the first output end of the computer control unit is connected to the input end of the AC servo motor, the AC servo motor is connected to the screw rod through a coupling, the slider moves on the screw rod to drive the transmission rod, and the transmission rod drives the wave-making plate. To control the movement of the wave-making plate, the first, 2...N output terminals of the N pressure sensors are respectively connected to the first, 2...N input terminals of the computer control unit, and the second output terminals of the computer control unit are connected to the wave height change display unit The input end is connected to collect the pressure signal generated by the wave and display the wave height change calculated by the computer control unit. The dry-back rocking plate wave maker and N pressure sensors are respectively installed on the inner wall of the deep water pool. N pressure sensors are distributed equidistantly below the wave-making plate along the vertical direction and submerged in water. At the same time, the pressure sensor on the top is required to keep a distance of 1-3cm from the bottom of the wave-making plate;

Experimental method, including the following steps:

Step 1. Set up the pressure sensor. Distribute N pressure sensors equidistantly below the wave-making plate along the vertical direction and immerse in the water. At the same time, it is also required to keep a distance of 1-3cm between the topmost pressure sensor and the bottom of the wave-making plate. Finally, N pressure sensors are installed on the inner wall of the deep water pool, N is a positive integer greater than 1, the larger N is, the higher the accuracy is, and at the same time, the number of N depends on the depth of the deep water pool;

Step 2. Collect pressure data, start the wave machine experimental device, and collect the pressure signals generated by N pressure sensors after the wave surface of the deep water pool is stable, and transmit these pressure signals to the computer control system;

Step 3, deduce the expression of wave pressure, according to existing formula, deduce the expression of wave generation pressure, describe by formula (1),

k₀表示波数，d表示水底到静水面的高度，k₀与ω满足色散关系ω²＝gk₀tanhk₀h，k_j表示方程ω²＝-gk_jtank_jh的第j个正解，z_n代表N个压强传感器所在水深，A₀和A_j是要求解的未知系数，t表示时间；In the formula, p _n represents the pressure measured by N pressure sensors, Re represents the real part, i represents the imaginary unit, ω represents the periodic swing angular frequency of the wave-making plate, ρ represents the density of water, Z ₀ (k ₀ ,z _n ) and Z _j (k _j , z _n ) represent the vertical characteristic function, where,

k ₀ represents the wave number, d represents the height from the water bottom to the still water surface, k ₀ and ω satisfy the dispersion relation ω ² =gk ₀ tanhk ₀ h, k _j represents the jth positive solution of the equation ω ² =-gk _j tank _j h, z _n represents the depth of water where N pressure sensors are located, A ₀ and A _j are unknown coefficients to be solved, and t represents time;

Step 4, solving the unknown coefficients, using the matrix equation (2) to solve in the computer control system through the measured pressure p _n , to obtain the unknown coefficients A ₀ and A _j ;

Step 5. Solve the change of wave height at the wave-making plate with time at time t, and calculate the relationship between the wave height at the wave-making plate and the unknown coefficient through the unknown coefficients A ₀ and A _j solved by the above steps, and use the known The wave height expression is described by the formula (3), and the unknown coefficient is brought in, and the computer control system is used for calculation, and then the change of the wave height with time at the wave-making plate at the time t is obtained, and finally the wave height change display unit output,

In the formula, g represents the acceleration of gravity, and z represents the height of the pressure sensor from the still water surface.

The beneficial effects of the present invention are: a wave maker experimental device and method based on point pressure feedback wave height display, wherein the experimental method includes the following steps: (1) setting a pressure sensor, (2) collecting pressure data, (3) Deduce the expression of wave pressure, (4) solve the unknown coefficient, (5) solve the change of wave height with time at the wave-making plate at time t. Compared with the existing technology, the experimental device uses a pressure sensor to measure the pressure generated by the wave on the wave-making plate, and finds the relationship between the pressure and the wave height, thereby realizing the conversion between the pressure and the wave height, avoiding the The waves in front of the wave-making plate are turbulent, and the wave height sequence values measured by the wave height sensor are very complex, making it difficult to accurately separate real-time reflected waves. The entire experimental device is simple in structure, easy to operate, safe and reliable.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the experimental device of the present invention.

In the figure: 1. Deep water pool, 2. N pressure sensors, 3. Dry back rocking plate wave maker, 3a, wave making plate, 3b, transmission rod, 3c, screw rod, 3d, slider, 3e, the first 1 bearing, 3f, the second bearing, 3g, coupling, 4, computer control system.

Fig. 2 is a flowchart of the steps of the experimental method of the present invention.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

As shown in Figure 1, a wave maker experimental device based on point pressure feedback and wave height display includes a deep water pool 1, a computer control system 4, a dry-back rocking plate wave maker 3 and N pressure sensors 2, computer controlled The system includes an AC servo motor, a computer control unit, and a wave height change display unit. The dry-back rocking plate wave maker 3 is provided with a wave-making plate 3a, a transmission rod 3b, first and second bearings 3e, 3f, and a slider 3d, screw 3c and coupling 3g, the wave-making plate 3a is connected to the transmission rod 3b, the transmission rod 3b is connected to the slider 3d, the slider 3d is inserted into the screw 3c, and the two ends of the screw 3c are respectively provided with The first and second bearings 3e, 3f, the first output end of the computer control unit are connected to the input end of the AC servo motor, the AC servo motor is connected to the screw rod 3c through the coupling 3g, and the slider 3d moves on the screw rod 3c to drive The transmission rod 3b, the transmission rod 3b drives the wave-making plate 3a to control the movement of the wave-making plate 3a, the first, 2...N output terminals of the N pressure sensors are respectively connected to the first, 2...N output ends of the computer control unit The input end is connected, and the second output end of the computer control unit is connected with the input end of the wave height change display unit, which is used to collect the pressure signal generated by the wave and display the wave height change calculated by the computer control unit. The wave-making machine 3 and N pressure sensors are installed on the inner wall of the deep water pool 1 respectively, and the N pressure sensors are distributed equidistantly below the wave-making plate 3a along the vertical direction and immersed in the water. The pressure sensor is kept at a distance of 1-3 cm from the bottom of the wave-making plate 3a.

As shown in Figure 2, the experimental method includes the following steps:

Step 1. Set up the pressure sensor. Distribute N pressure sensors equidistantly below the wave-making plate along the vertical direction and immerse in the water. At the same time, it is also required to keep a distance of 1-3cm between the topmost pressure sensor and the bottom of the wave-making plate. Finally, N pressure sensors are installed on the inner wall of the deep water pool, N is a positive integer greater than 1, the larger N is, the higher the accuracy is, and at the same time, the number of N depends on the depth of the deep water pool;

Step 2. Collect pressure data, start the wave machine experimental device, and collect the pressure signals generated by N pressure sensors after the wave surface of the deep water pool is stable, and transmit these pressure signals to the computer control system;

Step 3, deduce the expression of wave pressure, according to existing formula, deduce the expression of wave generation pressure, describe by formula (1),

k₀表示波数，d表示水底到静水面的高度，k₀与ω满足色散关系ω²＝gk₀tanhk₀h，k_j表示方程ω²＝-gk_jtank_jh的第j个正解，z_n代表N个压强传感器所在水深，A₀和A_j是要求解的未知系数，t表示时间；In the formula, p _n represents the pressure measured by N pressure sensors, Re represents the real part, i represents the imaginary unit, ω represents the periodic swing angular frequency of the wave-making plate, ρ represents the density of water, Z ₀ (k ₀ ,z _n ) and Z _j (k _j , z _n ) represent the vertical characteristic function, where,

k ₀ represents the wave number, d represents the height from the water bottom to the still water surface, k ₀ and ω satisfy the dispersion relation ω ² =gk ₀ tanhk ₀ h, k _j represents the jth positive solution of the equation ω ² =-gk _j tank _j h, z _n represents the depth of water where N pressure sensors are located, A ₀ and A _j are unknown coefficients to be solved, and t represents time;

Step 4, solving the unknown coefficients, using the matrix equation (2) to solve in the computer control system through the measured pressure p _n , to obtain the unknown coefficients A ₀ and A _j ;

Step 5. Solve the change of wave height at the wave-making plate with time at time t, and calculate the relationship between the wave height at the wave-making plate and the unknown coefficient through the unknown coefficients A ₀ and A _j solved by the above steps, and use the known The wave height expression is described by the formula (3), and the unknown coefficient is brought in, and the computer control system is used for calculation, and then the change of the wave height with time at the wave-making plate at the time t is obtained, and finally the wave height change display unit output,

In the formula, g represents the acceleration of gravity, and z represents the height of the pressure sensor from the still water surface.

Claims (1)

1. An experimental method of a wave making machine experimental device based on point pressure feedback wave height display is characterized in that: the wave maker experimental device comprises a deep water pool, a computer control system, a dry-back type rocking plate wave maker and N pressure sensors, wherein the computer control system comprises an alternating current servo motor, a computer control unit and a wave height change display unit, the dry-back type rocking plate wave maker is provided with a wave making plate, a transmission rod, a 1 st bearing, a 2 nd bearing, a sliding block, a screw rod and a coupling, the wave making plate is connected with the transmission rod, the transmission rod is connected with the sliding block, the sliding block is sleeved on the screw rod, the 1 st bearing and the 2 nd bearing are respectively arranged at two ends of the screw rod, the 1 st output end of the computer control unit is connected with the input end of the alternating current servo motor, the alternating current servo motor is connected with the screw rod through the coupling, the sliding block moves on the screw rod to drive the transmission rod, the transmission rod drives the wave making plate and is used for controlling the movement of the wave making plate, the N pressure sensors are 1 st and 2 \8230, the N output ends are respectively connected with the computer control units 1 st and 2 \8230, the N input ends are connected, the 2 nd output end of the computer control unit is connected with the input end of the wave height change display unit and is used for collecting pressure signals generated by waves and displaying the wave height change condition calculated by the computer control unit, the dry-back type wave shaking plate wave making machine and the N pressure sensors are respectively arranged on the inner wall of the deep water pool, the N pressure sensors are equidistantly distributed below the wave making plate along the vertical direction and are immersed in the water, and meanwhile, the distance between the topmost pressure sensor and the bottom of the wave making plate is required to be kept between 1 and 3 cm;

the experimental method comprises the following steps:

step 1, arranging pressure sensors, distributing N pressure sensors below a wave making plate at equal intervals along the vertical direction and immersing the pressure sensors in water, and meanwhile, requiring the distance between the topmost pressure sensor and the bottom of the wave making plate to be 1-3cm, and finally installing the N pressure sensors on the inner wall of the deep water pool;

step 2, collecting pressure data, starting the wave maker experimental device, collecting pressure signals generated by N pressure sensors after the wave surface of the deep water pool is stable, and transmitting the pressure signals to a computer control system;

step 3, deducing an expression of wave pressure, deducing an expression of pressure generated by waves according to the existing formula, describing through the formula (1),

in the formula, p _n The pressure measured by N pressure sensors is represented, the value range of N is 1 to N, re represents the real part, i represents an imaginary number unit, omega represents the periodic swing angular frequency of the wave making plate, rho represents the density of water, Z ₀ (k ₀ ，z _n ) And Z _j (k _j ，z _n ) A vertical characteristic function is represented, wherein,

k ₀ denotes wave number, d denotes height from water bottom to still water surface, k ₀ Satisfies the dispersion relation omega with omega ² ＝gk ₀ tank ₀ h，k _j Expression equation ω ² ＝-gk _j tank _j J-th positive solution of h, z _n Representing the depth of water in which the N pressure sensors are located, A ₀ And A _j Is the unknown coefficient to be solved, t represents time;

step 4, solving unknown coefficient, and measuring pressure p _n Solving in computer control system by using matrix equation (2) to obtain unknown coefficient A ₀ And A _j ；

Step 5, solving the change of the wave height along with the time at the wave making plate at the moment t, and solving the unknown coefficient A through the steps ₀ And A _j Calculating the relation between the wave height at the wave-making plate and the unknown coefficient, describing by a formula (3) by using a known wave height expression, substituting the unknown coefficient, calculating by using a computer control system, further solving the change of the wave height eta at the wave-making plate along with the time at the moment t, and finally outputting by a wave height change display unit,

in the formula, g represents the gravitational acceleration, and z represents the height of the pressure sensor from the hydrostatic surface.

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