Synthesis algorithm of omnidirectional focused waves in circular harbor

Abstract

The present invention relates to the technical field of focused waves and discloses an omnidirectional focused wave synthesis algorithm for a circular harbor. The algorithm utilizes spectral phase focusing to generate focused waves. At the focal point in space and time, all component waves are superimposed with zero phase to form a focused wave. The focused wave is analyzed and the displacement curves of a plurality of circularly arranged wave-making plates on the periphery of the circular harbor are obtained by reverse deduction. The omnidirectional focused wave synthesis algorithm for a circular harbor provided by the present invention overcomes the difficulties in studying extreme waves and utilizes the unique symmetry of a circular harbor wave maker to achieve simulated generation of extreme focused waves and graphic-type focused waves, such as single-peak focused waves, double-peak focused waves, eccentric focused waves, rotating focused waves, graphic-type focused waves and other focused waveforms. The algorithm can provide technical support for the simulation of various random, steep and highly destructive abnormal waves caused by extreme sea conditions such as deep-sea storms, tsunamis and super typhoons.

Description

Technical Field

[0001] The patent of this invention relates to the technical field of focused waves, specifically, to an algorithm for synthesizing omnidirectional focused waves in a circular harbor. Background Art

[0002] Extreme focused waves have the characteristics of high wave height, concentrated energy, strong nonlinearity, and unpredictable appearance and disappearance. They pose a huge threat to marine structures and ships and are an important research object in extreme sea condition wave model experiments.

[0003] my country started research on wave simulation later than other countries. Domestic scholars have been continuously exploring and researching in this area. Many researchers are committed to the development of wave-making pools and conducting research on wave generation in large, high-power irregular pools. my country has also established many large-scale experimental pools.

[0004] At present, my country has at least 40 large-scale test pools, all of which are rectangular wave-making pools, which are suitable for marine environment simulation in most application scenarios such as nearshore and shallow seas. Faced with the complex wind, wave and current marine environmental conditions in the deep sea, it is impossible to achieve omnidirectional extreme wave simulation, completely reproduce extreme sea conditions in wave model tests, and complete reliability verification tests of marine technology equipment in extreme marine environments. Functionally, it is difficult to meet the more complex deep-sea extreme sea condition simulation needs. Summary of the Invention

[0005] The purpose of the present invention is to provide an omnidirectional focused wave synthesis algorithm for a circular harbor to meet the scientific experimental requirements for simulating extremely complex sea conditions.

[0006] The present invention is achieved by using an omnidirectional focused wave synthesis algorithm for a circular harbor basin. This algorithm utilizes spectral phase focusing to generate a focused wave. At the focal point in space and time, all component waves are superimposed with zero phase to form a focused wave. By analyzing the focused wave, the displacement curves of multiple circularly arranged wave-making plates on the periphery of the circular harbor basin are inferred.

[0007] According to the linear superposition theory, the free surface of the wave at any point It is expressed as the result of superposition of regular waves of different frequencies and directions, as shown in the following formula (1):

[0008] Formula (1);

[0009] in: The frequency is , the direction angle is The amplitude of the component waves, is the wave number of the composition wave, is the initial phase of the wave, and are the frequency and direction numbers of the component waves respectively;

[0010] Component wave angular frequency and wave number Satisfies the linear dispersion relation, as shown in formula (2):

[0011] Formula (2);

[0012] in: the depth of the circular harbor basin;

[0013] Set the wave to a specified time Focus on position , satisfying the following formula (3):

[0014] Formula (3);

[0015] The initial phase of each component wave satisfies the following formula (4):

[0016] Formula (4);

[0017] Waves at a given moment Wave height at The following formula (5);

[0018] Formula (5);

[0019] Set the circular harbor wave generator to be located at At a designated location in the circular harbor To generate focused waves, the motion functions of each wave-making plate are as follows:

[0020] Formula (6);

[0021] Formula (7);

[0022] in, is the transfer function of the circular harbor wave maker, is the spectrum function of the constituent waves, is the change value of the angular frequency of the component wave, is the change in the component wave direction angle.

[0023] Preferably, the discrete frequencies of the constituent waves are set Distributed in Within the frequency range, the width of the frequency interval that defines the wave and center frequency They are:

[0024] , Formula (8);

[0025] The wave surface characteristics are expressed as a function of the following parameters:

[0026] Formula (9).

[0027] Compared with the existing technology, the circular harbor omnidirectional focused wave synthesis algorithm provided by the present invention breaks through the difficulties in extreme wave research. By utilizing the unique symmetry of the circular harbor wave maker, it realizes the simulation generation of extreme focused waves and graphic-type focused waves, such as single-peak focused waves, double-peak focused waves, eccentric focused waves, rotating focused waves, graphic-type focused waves and other focused waveforms. It can provide technical support for the simulation of various random, steep, and highly destructive deformed waves caused by extreme sea conditions such as deep-sea storms, tsunamis, and super typhoons. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the operation of the circular harbor omnidirectional focused wave synthesis algorithm provided by the present invention;

[0029] Figure 2 It is a schematic diagram of the circular harbor partition of the elliptical focused wave provided by the present invention;

[0030] Figure 3 It is the reference coordinate system of the circular harbor provided by the present invention;

[0031] Figure 4 It is a schematic diagram of the focusing position of the D-shaped focusing wave provided by the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] The implementation of the present invention is described in detail below with reference to specific embodiments.

[0034] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0035] Reference Figure 1-4 The figure shows a preferred embodiment of the present invention.

[0036] The circular harbor omnidirectional focused wave synthesis algorithm uses spectral phase focusing to generate focused waves. At the focal point in space and time, all component waves are superimposed with zero phase to form a focused wave. By analyzing the focused wave, the displacement curves of multiple circularly arranged wave-making plates on the periphery of the circular harbor are inferred.

[0037] According to the linear superposition theory, the free surface of the wave at any point It is expressed as the result of superposition of regular waves of different frequencies and directions, as shown in the following formula (1):

[0038] Formula (1);

[0039] in: The frequency is , the direction angle is The amplitude of the component waves, is the wave number of the composition wave, is the initial phase of the wave, and are the frequency and direction numbers of the component waves respectively;

[0040] Component wave angular frequency and wave number Satisfies the linear dispersion relation, as shown in formula (2):

[0041] Formula (2);

[0042] in: the depth of the circular harbor basin;

[0043] Set the wave to a specified time Focus on position , satisfying the following formula (3):

[0044] Formula (3);

[0045] The initial phase of each component wave satisfies the following formula (4):

[0046] Formula (4);

[0047] Waves at a given moment Wave height at The following formula (5);

[0048] Formula (5);

[0049] Set the circular harbor wave generator to be located at At a designated location in the circular harbor To generate focused waves, the motion functions of each wave-making plate are as follows:

[0050] Formula (6);

[0051] Formula (7);

[0052] in, is the transfer function of the circular harbor wave maker, is the spectrum function of the constituent waves, is the change value of the angular frequency of the component wave, is the change in the component wave direction angle.

[0053] The circular harbor omnidirectional focused wave synthesis algorithm provided above breaks through the difficulties in extreme wave research. By utilizing the unique symmetry of the circular harbor wave maker, it realizes the simulation generation of extreme focused waves and graphic-type focused waves, such as single-peak focused waves, double-peak focused waves, eccentric focused waves, rotational focused waves, graphic-type focused waves and other focused waveforms. It can provide technical support for the simulation of various random, steep, and highly destructive deformed waves caused by extreme sea conditions such as deep-sea storms, tsunamis, and super typhoons.

[0054] The circular harbor omnidirectional focused wave synthesis algorithm realizes the synthesis of extreme focused waves, filling the gap in my country's key technologies for simulating extreme sea conditions, meeting the scientific experimental needs of simulating extremely complex sea conditions, and providing a wave model test platform for dynamic performance testing and reliability verification of deep-sea marine technology equipment, deep-water oil and gas drilling platforms, marine energy equipment, etc., which is conducive to the rapid prototype verification and optimization of deep-sea marine technology equipment, and provides strong technical support for the localization of major marine scientific equipment in my country.

[0055] At the same time, the circular harbor focusing wave synthesis algorithm also completed the precise control of parameters such as focusing position, height, diameter, roundness, and verticality, and successfully simulated and generated single-peak focusing with controllable coarseness, eccentric focusing waves with controllable verticality, and elliptical focusing waves with controllable length and short axes, meeting the scientific experiments' simulation accuracy requirements for real extremely harsh marine environments.

[0056] in, is the transfer function of the circular harbor wave maker, It is the spectrum function of the wave. Different waveforms correspond to different spectrum functions, which can be searched according to the specifications.

[0057] In this embodiment, the discrete frequencies of the constituent waves are set Distributed in Within the frequency range, the width of the frequency interval that defines the wave and center frequency They are:

[0058] , Formula (8);

[0059] The wave surface characteristics are expressed as a function of the following parameters:

[0060] Formula (9).

[0061] Based on the above algorithms, wave algorithms for single-peak focused wave, elliptical focused wave, eccentric focused wave, double-peak focused wave, rotational focused wave, and D-shaped focused wave are written respectively. However, each focused wave needs to be considered separately according to its characteristics, and the main differences are in the parameter settings such as frequency width, center frequency, focusing time, focusing position, and focusing wave height.

[0062] (1) Single-peak focused wave

[0063] In a circular harbor, all wave generators have the same parameters, so only the individual wave generator settings need to be considered. The focusing point of the focused wave is located at the center of the circular harbor, with the focusing position equal to the radius. Setting a reasonable component wave frequency width allows for a wider frequency range, higher focusing efficiency, and greater adaptability. Setting a reasonable center frequency allows the primary frequency to move closer to low frequencies, increasing the proportion of low-frequency component waves and achieving a more pronounced focusing effect.

[0064] The above refers to the parameter settings of a single wave maker. All setting parameters of all wave makers are the same. The settings of frequency-related parameters based on single-peak focused waves can be applied to other types of focused waves.

[0065] In actual tests, at a water depth of only 0.3m, the circular harbor wave maker of Zhuhai Institute of Science and Technology can synthesize single-peak focused waves up to 10m in height, with a jet amplification ratio of more than 30 times (wave height to water depth ratio), extremely strong energy and high impact speed, fully meeting the needs of model test research on the structural reliability and capsizing risk of deep-water oil and gas drilling platforms, offshore wind turbines, ships, etc.

[0066] In the early stages of jet evolution, it appears as a smooth upward-rushing water column. At 5 m, a jet begins to appear in the upper part of the water column. At 7.5 m, the jet becomes obvious. Finally, the jet completely breaks up when it reaches 9.7 m. The formation of the upward-rushing jet is a highly nonlinear phenomenon, which indicates that the wave-making process is well controlled and the wave-making quality is extremely high.

[0067] (2) Elliptical focused wave

[0068] In the case of elliptical focusing, the focusing positions of all wave makers in the circular harbor are different, but the other parameters are the same.

[0069] The wave generators in the circular harbor basin are divided into four groups, with different focusing positions set for each zone. For example, a set of 32 circular wave generator units is divided into four sections: wave generators 1-6 and 28-32 form Zone 1, wave generators 7-11 form Zone 2, wave generators 12-22 form Zone 3, and wave generators 23-27 form Zone 4. Points on the elliptical curve represent the wave generator's focal points. The focusing positions of wave generators in Zones 1 and 3 are set according to the major axis of the ellipse, while those in Zones 2 and 4 are set according to the minor axis of the ellipse. This creates an elliptical cross-section of the water column formed by the focusing.

[0070] (3) Eccentric focused wave

[0071] In the case of eccentric focusing, the focusing position and focusing wave height of all wave makers in the circular harbor are different, while the other parameters are the same. The circular harbor adopts the Cartesian coordinate system to calculate the focusing point (x b ,y b ) and the wave generators as the focal position. Due to eccentricity, the wave fields generated by small fan-shaped wave generators near the focal point are more energetic, while those generated by large fan-shaped wave generators farther away are less energetic. This causes the wave fields in both areas to tilt toward the weaker large fan-shaped wave generators when they converge at the focal point. Therefore, the focused wave heights of some wave generators need to be adjusted to ensure that the wave fields in both areas have roughly the same energy and the water column is vertical.

[0072] The focused wave height of the one or two wave makers farthest from the focusing point is multiplied by a correction coefficient greater than 1, and the correction coefficients of the remaining wave makers are linearly reduced to 1 in the order of their distance from the wave makers. In this way, the energy of the wave field in the circular harbor is evenly distributed, and the eccentrically focused water column generated is also vertically upward.

[0073] Alternatively, a delayed focusing method may be used to extend the focusing time of a small fan-shaped wave maker close to the focusing point on the basis of the original focusing time, thereby also achieving the effect of vertical focusing.

[0074] The method of setting the focused wave height correction factor can also be used to control the inclination of the focused water column. Based on the critical correction factor that makes the water column vertical, if the correction factor is set to be less than the critical correction factor, the focused water column will tilt outward from the circular pool. If the correction factor is greater than the critical correction factor, the water column will tilt inward from the circular pool.

[0075] (4) Double-peak focused wave

[0076] In the case of double-peak focusing, similar to eccentric focusing, the focus positions of all wave makers are different, and the other parameters are the same, but the problem of how to allocate the wave makers to the two focusing points must be considered. Using the Cartesian coordinate system, design the two focusing points (x b1 ,yb1 )、(x b2 ,y b2 ), using the wave machine interval control method, taking 32 circular wave machine units as an example, let the focus of the 1st, 3rd, 5th...31st wave machine be (x b1 ,y b1 ), the focusing point of the wave generator No. 2, 4, 6...32 is (x b2 ,y b2 ), and calculate the corresponding focus positions respectively. This method can avoid the problem of uneven energy distribution in the wave field.

[0077] (5) Rotating focused wave

[0078] In the case of rotating focusing, the start-up time of all wave makers in the circular harbor is different, while all other parameters are the same. All wave makers are set to have the same focusing wave height and focusing time, with the focusing position a certain distance away from the center of the circle (i.e., the radius of the rotating circle). Starting with wave maker No. 1, the start-up time of subsequent wave makers is extended by the same amount, delaying the focusing time of each wave maker in turn, thus creating a rotating focusing effect.

[0079] The above parameter settings are for one rotation. To achieve continuous focusing for n rotations, select a portion of the wave array from wave generator #1 (the primary data for focusing) and repeat it n times. Smooth the data from the beginning to the end, using this processed data as the displacement time series for all plates. Then, set the activation interval between adjacent wave generators based on the selected wave array length. This will produce a focused wave that rotates n times continuously.

[0080] (6) Graphic focused waves

[0081] In the case of graphical focusing, the focal positions of all wave generators in a circular harbor basin are different, while all other parameters remain the same. For example, using 32 circular wave generator units, the graphic is placed in the circular harbor basin coordinate system. The radial focusing point for each wave generator is identified, corresponding to 32 points in total. The radial distance from each point to the wave generator is calculated, corresponding to the focal position of each of the 32 wave generators. For example, a D-shaped focused wave is shown in the figure, illustrating the position of the letter D in a circular harbor basin.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Circular harbor omnidirectional focused wave synthesis algorithm, characterized by: Spectral phase focusing is used to generate focused waves. At the focal point in space and time, all component waves are superimposed with zero phase to form a focused wave. By analyzing the focused wave, the displacement curves of multiple circularly arranged wave-making plates on the periphery of the circular harbor are obtained. According to the linear superposition theory, the free surface η(x, y, t) of a wave at any point is expressed as the result of the superposition of regular waves of different frequencies and directions, as shown in the following formula (1): Among them: a ij The frequency is f i , direction angle is θ j The amplitude of the component waves, k i is the wave number of the composition wave, is the initial phase of the wave, N f and N θ are the frequency and direction numbers of the component waves respectively; Angular frequency of the component wave ω i and wave number k i Satisfies the linear dispersion relation, as shown in formula (2): Where: h is the depth of the circular harbor; Set the wave at the specified time t=t b Focus on position (x b ,y b ), satisfying the following formula (3): The initial phase of each component wave satisfies the following formula (4): The wave at a given time t = t b The wave height η(x, y, t) at t is as follows: The circular harbor wave generator is set at x = 0m, and the specified position (x b ,y b ) generates focused waves, and the motion functions of each wave-making plate are as follows: Among them, T(f i ,θ j ) is the transfer function of the circular harbor wave maker, S(ω i ,θ j ) is the spectrum function of the constituent waves, Δω i is the change in the angular frequency of the component wave, Δθ j is the change in the component wave direction angle.

2. The circular harbor omnidirectional focused wave synthesis algorithm according to claim 1, characterized in that: Set the discrete frequencies f of the constituent waves i Distributed in [f1,f n ] frequency range, define the frequency interval width Δf and center frequency f of the component wave c They are: The wave surface characteristics are expressed as a function of the following parameters: η = f[N f , N θ , a, f c , Δf, (x b , y b ), t b , α, h] Equation (9).

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