Method for calculating reflection coefficient of open caisson and computer readable storage medium

Abstract

A calculation method for a reflection coefficient of a perforated caisson is characterized by comprising the following steps: acquiring the width B of a wave dissipation chamber of the perforated caisson in an engineering project, the porosity xi of gravel filled in the perforated caisson, the gradient gamma of a gravel slope in the perforated caisson, the water depth d of an environment where the perforated caisson is located and the wavelength L of an incident wave of the environment where the perforated caisson is located; then, the reflection coefficient Kr of the open caisson with the gravel slope inside in the engineering project is obtained through a calculation formula; and when a computer program of the computer readable storage medium is executed by the processor, the calculation method of the reflection coefficient of the open caisson is realized. Therefore, the reflection coefficient of the perforated caisson internally provided with the gravel slope is obtained through a calculation formula, a numerical model test or a physical model test is not needed, manpower and material resources are saved, and theoretical basis and reference are provided for wave dissipation structure design and construction of port engineering projects.

Description

Technical Field

[0001] The present invention relates to the field of marine engineering technology, and in particular to a method for calculating a reflection coefficient of an open-hole caisson and a computer-readable storage medium. Background Art

[0002] The continuous expansion of port engineering into deep-water areas has put forward higher requirements for the design of wave-breaking structures. At present, the reflection coefficient is often used to reflect the wave-breaking effect of the structure. The method for obtaining the reflection coefficient of the wave-breaking structure in the prior art is shown in the Chinese invention application with patent application number CN202210230173.7 (application publication number CN114580317A), which constructs a numerical simulation water tank and uses a mass source to generate waves; obtains the spatial distribution curve of the free liquid surface height of the synthetic reflected wave; and calculates the wave height H of the synthetic reflected wave according to the spatial distribution curve of the free liquid surface height of the synthetic reflected wave. 合 ; Then use the formula to calculate the reflected wave height H 反 , and thus the reflection coefficient is obtained.

[0003] Although the reflection coefficient of the floating breakwater can be obtained by the above method, this method is not applicable to other wave-breaking structures, such as the perforated caisson wave-breaking structure. Perforated caissons are of various forms, and usually achieve the purpose of wave breaking based on the different phases of the incident wave and the reflected wave. In order to adapt to various engineering backgrounds, new perforated caissons have also emerged, including perforated caissons with gravel slopes inside, curved perforated caissons, etc. Among them, the perforated caissons with gravel slopes inside can achieve better wave-breaking effects by transforming the existing docks because they combine the wave-breaking advantages of slopes and perforated caissons. However, there are many factors that affect the wave-breaking performance of perforated caissons with gravel slopes inside, such as the relative width of the wave-breaking chamber, the relative water depth, the slope of the internal gravel slope, and the porosity of the filled gravel. Under the influence of these factors, the above method cannot be used to calculate the reflection coefficient of the perforated caisson with gravel slope inside. If numerical simulation and physical model test are used to calculate the reflection coefficient of the open caisson with gravel slope inside, a lot of manpower and material resources will be required, and different test models need to be designed according to the characteristics of each port engineering project, which is not convenient for providing theoretical basis and reference for the design and construction of wave-breaking structures of related port engineering. Therefore, it is necessary to further improve the calculation method of the reflection coefficient of the open caisson with gravel slope inside. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide a method for calculating the reflection coefficient of an open-hole caisson with a gravel slope inside in view of the above-mentioned existing technical status.

[0005] The second technical problem to be solved by the present invention is to provide a computer-readable storage medium storing a calculation method capable of quickly calculating the reflection coefficient of an open-hole caisson with a gravel slope inside, in response to the above-mentioned existing technical status.

[0006] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: the reflection coefficient calculation method of the perforated caisson is characterized by: obtaining the wave-breaking chamber width B of the perforated caisson in the engineering project, the porosity ξ of the gravel filled inside the perforated caisson, the slope γ of the gravel slope inside the perforated caisson, the water depth d of the environment where the perforated caisson is located, and the wavelength L of the incident wave in the environment where the perforated caisson is located, and then obtaining the reflection coefficient K of the perforated caisson with a gravel slope inside the engineering project through the following formula r :

[0007]

[0008] Preferably, the reflection coefficient K r The applicable range of each parameter in the calculation formula is: relative to the width of the wave-breaking chamber Relative water depth The porosity of the filled gravel is ξ=0.25-0.50, the slope of the gravel slope is γ=0.5-1.0, and the reflection coefficient K r The calculation formula is applicable to the following ranges of incident wave height H, wave period T and water depth d: incident wave height H = 1 ~ 2m, incident wave period T = 3.58 ~ 10.29s, water depth d = 8 ~ 10m.

[0009] Preferably, the reflection coefficient K r The calculation formula is obtained through the following steps:

[0010] S1. Establish a physical model of an open caisson with a gravel slope inside;

[0011] S2. Using the physical model established in S1, multiple model tests are conducted to obtain multiple test values ​​of reflection coefficients. The slope γ of the gravel slope, the porosity ξ of the filled gravel, the wave height H of the incident wave, the wave period T of the incident wave, or the water depth d of each model test are different.

[0012] S3, based on the test values ​​of multiple groups of reflection coefficients obtained in S2, the reflection coefficient K is obtained by least squares fitting. r The calculation formula for .

[0013] Preferably, the step of establishing a physical model of an open-hole caisson with a gravel slope inside in S1 comprises the following steps:

[0014] S11. Make a model of an open-hole caisson, the model having a wave-breaking chamber, arrange a wave maker and the model at both ends of the water tank, and provide three wave height meters equidistantly arranged in front of the model;

[0015] S12, filling gravel in the wave-breaking chamber of the model made in S11, the gravel forming a gravel slope in the wave-breaking chamber, and obtaining the slope of the gravel slope and the porosity of the filled gravel;

[0016] S13, filling water into the water tank, and after the water filling is completed, obtaining the water depth in front of the model;

[0017] S14, starting a wave maker to generate incident waves in the water tank, and obtaining wave information of the incident waves.

[0018] Preferably, the space in the model in S11 is divided into a front cabin and a rear cabin by a partition wall, the front cabin is a wave-breaking chamber, and a through hole is provided at the front end of the front cabin for waves to flow in.

[0019] Preferably, the distance between the wave height meter and the model in S11 is greater than or equal to 0.2L, and the distance between two adjacent wave height meters is 0.05L to 0.45L, where L is the wavelength of the incident wave.

[0020] Preferably, the porosity of the packed gravel is obtained in S12 using the following formula:

[0021]

[0022] Where: ξ is the porosity of the packed gravel, V 1 is the total volume of the slope filled with gravel, M 3 is the total mass of gravel filling the slope, ρ 3 Fill the slope part with crushed stone density.

[0023] Preferably, the wave information of the incident wave in S14 includes the wave height of the incident wave, the wavelength of the incident wave and the wave period of the incident wave.

[0024] Preferably, obtaining the test value of the reflection coefficient in S2 comprises the following steps:

[0025] S21, obtaining test results of three wave height meters in each model test;

[0026] S22. Based on the test results of the wave height meter obtained in S21, the Gado two-point method is used to separate the incident wave and the reflected wave, so as to calculate the test value of the reflection coefficient of each physical model test.

[0027] The technical solution adopted by the present invention to solve the above-mentioned second technical problem is: a computer-readable storage medium, which stores a computer program and can be read and executed by a processor, and is characterized in that: when the computer program is executed by the processor, it implements the reflection coefficient calculation method of the open-hole caisson as mentioned above.

[0028] Compared with the prior art, the advantages of the present invention are: the present application utilizes the width of the wave-breaking chamber of the perforated caisson, the porosity of the filled gravel, the slope of the gravel slope, the water depth and the wavelength of the incident wave to calculate the reflection coefficient of the perforated caisson with a gravel slope inside, without the need for numerical model tests or physical model tests, thus saving manpower and material resources, and providing a theoretical basis and reference for the design and construction of wave-breaking structures for port engineering projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a layout diagram of a physical test model of Example 1 of the present invention;

[0030] Figure 2 This is a relationship diagram of the test value of the relative wave-breaking chamber width and the reflection coefficient under different incident wave heights in Example 1 of the present invention;

[0031] Figure 3 This is a relationship diagram of the experimental values ​​of the relative wave-breaking chamber width and the reflection coefficient under different porosities of the filled gravel in Example 1 of the present invention;

[0032] Figure 4 This is a relationship diagram of the slope of the gravel slope and the test value of the reflection coefficient under different wave periods in Example 1 of the present invention;

[0033] Figure 5 This is a relationship diagram of the experimental values ​​of the porosity of the filled gravel and the reflection coefficient under different wave periods in Example 1 of the present invention, when the slope of the gravel slope is 1:1.2;

[0034] Figure 6 This is a relationship diagram of the experimental values ​​of the porosity of the filled gravel and the reflection coefficient under different wave periods in Example 1 of the present invention, when the slope of the gravel slope is 1:2.0;

[0035] Figure 7 A comparison diagram of the calculated value of the reflection coefficient obtained by the calculation formula in Example 1 of the present invention and the experimental value of the reflection coefficient;

[0036] Figure 8 It is a comparison chart of the calculated value of the reflection coefficient obtained by the calculation formula in Example 1 of the present invention and the experimental value of the reflection coefficient obtained by the physical model in the prior art. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the accompanying drawings.

[0038] like Figures 1 to 8 Shown is the best embodiment 1 of the present invention.

[0039] The reflection coefficient calculation method of the perforated caisson of the present embodiment is used to calculate the perforated caisson with a gravel slope inside. First, the width B of the wave-breaking chamber of the perforated caisson in the project, the porosity ξ of the gravel filled inside the perforated caisson, the slope γ of the gravel slope inside the perforated caisson, the water depth d of the environment where the perforated caisson is located, and the wavelength L of the incident wave in the environment where the perforated caisson is located are obtained. Then, the reflection coefficient K of the perforated caisson with a gravel slope inside the project is obtained by the following formula: r :

[0040]

[0041] Reflection coefficient K r The applicable range of each parameter in the calculation formula is: relative to the width of the wave-breaking chamber Relative water depth The porosity of the packed gravel is ξ=0.25~0.50, the slope of the gravel slope is γ=0.5~1.0, and the reflection coefficient is K r The calculation formula is applicable to the following ranges of incident wave height H, wave period T and water depth d: incident wave height H = 1 ~ 2m, incident wave period T = 3.58 ~ 10.29s, water depth d = 8 ~ 10m.

[0042] The reflection coefficient K of this embodiment r The calculation formula is obtained through the following steps:

[0043] S1. Establish a physical model of an open caisson with a gravel slope inside;

[0044] Specifically, S1 includes the following steps:

[0045] S11. First, a model of a perforated caisson is made. The space inside the model is divided into a front cabin and a rear cabin by a partition wall. The front cabin is a wave-breaking chamber. A through hole is provided at the front end of the front cabin for waves to flow in. Then, a wave maker and a model are arranged at both ends of the water tank. Finally, three wave height meters are arranged at equal intervals in front of the model. The distance between the wave height meter and the model is greater than or equal to 0.2L. The distance between two adjacent wave height meters is 0.05L to 0.45L, and L is the wavelength of the incident wave.

[0046] The model of the perforated caisson in this embodiment is made of 10 mm thick acrylic plexiglass, with a geometric scale of 1:20. The model of the perforated caisson is arranged 45 m away from the wave maker, the distance between the front end of the model and the nearest wave height meter is 1.7 m, and the distance between two adjacent wave height meters is 0.3 m. The physical test model is arranged as follows: Figure 1 As shown;

[0047] S12, filling gravel in the wave-breaking chamber of the model made in S11, the gravel forming a gravel slope in the wave-breaking chamber, obtaining the slope of the gravel slope and the porosity of the filled gravel, and obtaining the porosity of the filled gravel using the following formula:

[0048]

[0049] Where: ξ is the porosity of the packed gravel, V 1 is the total volume of the slope filled with gravel, M 3 is the total mass of gravel filling the slope, ρ 3 V is the density of gravel filled in the slope; 1 It can be calculated by the size of the open caisson and changes with the gradient of the gravel slope, ρ 3 The stones used to fill the slopes in a number of tests were randomly selected and calculated using the drainage method;

[0050] S13, filling water into the water tank, and after the water filling is completed, obtaining the water depth in front of the model;

[0051] S14, starting a wave maker to generate incident waves in the water tank, and obtaining wave information of the incident waves;

[0052] The incident wave of this embodiment is a regular wave, and the wave information of the incident wave includes the wave height of the incident wave, the wavelength of the incident wave, and the wave period of the incident wave;

[0053] S2. Using the physical model established in S1, multiple model tests are conducted to obtain multiple test values ​​of reflection coefficients. The slope γ of the gravel slope, the porosity ξ of the filled gravel, the wave height H of the incident wave, the wave period T of the incident wave, or the water depth d of each model test are different.

[0054] Specifically, obtaining the test value of the reflection coefficient in S2 includes the following steps:

[0055] S21, obtaining test results of three wave height meters in each model test;

[0056] S22, based on the test results of the wave height meter obtained in S21, the Gado two-point method is used to separate the incident wave and the reflected wave, so as to calculate the test value of the reflection coefficient of each physical model test;

[0057] The physical model of this embodiment is subjected to multiple model tests, and the slope of the gravel slope, the porosity of the filled gravel, the wave height of the incident wave, the wave period of the incident wave, or the water depth of each model test is different. That is, in the process of the physical model test of this embodiment, the width of the wave-breaking chamber of the perforated caisson is 0.27m, the wave height of the incident wave is 0.05m, 0.075m and 0.1m respectively, and the water depth is 0.40m, 0.45m and 0.50m respectively. The slopes of the gravel slopes are 1:1.0, 1:1.2, 1:1.5, and 1:2.0, respectively. The porosities of the filled gravel are 0.25, 0.40, 0.45, and 0.50, respectively. The wave periods of the incident waves are 0.8s, 0.9s, 1.0s, 1.2s, 1.4s, 1.6s, 1.8s, 2.0s, and 2.3s, respectively. The physical model test conditions of the caisson with a gravel slope opening are shown in Table 1.

[0058] Table 1 Physical model test conditions of caisson with gravel slope and opening inside

[0059]

[0060] (1) Keeping the water depth, wave height of the incident wave, porosity of the filling gravel, slope of the gravel slope and width of the wave-breaking chamber unchanged, the relative width of the wave-breaking chamber is changed by changing the wavelength of the incident wave. The relative width of the wave-breaking chamber is B is the width of the wave-breaking chamber, and L is the wavelength of the incident wave, so the relationship between the relative width of the wave-breaking chamber and the experimental value of the reflection coefficient is obtained, such as Figure 2 and Figure 3 As shown in Figure 2, the experimental value of the reflection coefficient has a nonlinear relationship with the relative width of the wave-breaking chamber; Figure 2 It is the relationship diagram between the relative width of the wave-breaking chamber and the experimental value of the reflection coefficient under different incident wave heights. The horizontal axis is the relative width of the wave-breaking chamber, and the vertical axis is the experimental value of the reflection coefficient. Figure 3 The graph is a relationship between the relative width of the wave-breaking chamber and the experimental value of the reflection coefficient under different porosities of the gravel filling. The horizontal axis is the relative width of the wave-breaking chamber, and the vertical axis is the experimental value of the reflection coefficient.

[0061] (2) Keep the width of the wave-breaking chamber, the wave height of the incident wave, the porosity of the filling gravel, and the water depth unchanged, that is, the wave height of the incident wave H = 0.05m, the porosity of the filling gravel ξ = 0.4, and the water depth d = 0.4m, and change the slope of the gravel slope to obtain the relationship between the slope of the gravel slope and the test value of the reflection coefficient. Figure 4 is a graph showing the relationship between the slope of the gravel slope and the test value of the reflection coefficient under different wave periods, with the abscissa being the slope of the gravel slope and the ordinate being the test value of the reflection coefficient;

[0062] (3) Keep the width of the wave-breaking chamber, the incident wave height, the internal gravel slope and the water depth unchanged, and change the porosity of the filling gravel to obtain the relationship between the porosity of the filling gravel and the test value of the reflection coefficient, such as Figure 5 and Figure 6 As shown in Figure 2, the porosity of the packed gravel has a nonlinear relationship with the experimental value of the reflection coefficient; Figure 5 The relationship between the porosity of the filled gravel and the test value of the reflection coefficient under different wave periods when the slope of the gravel slope is 1:1.2, the abscissa is the porosity of the filled gravel, and the ordinate is the test value of the reflection coefficient; Figure 6 The relationship between the porosity of the filled gravel and the test value of the reflection coefficient under different wave periods when the slope of the gravel slope is 1:2.0, the abscissa is the porosity of the filled gravel, and the ordinate is the test value of the reflection coefficient;

[0063] S3, based on the test values ​​of multiple sets of reflection coefficients obtained in S2, the reflection coefficient K is obtained by least squares fitting. r The calculation formula is:

[0064]

[0065] In the formula, K r is the reflection coefficient, B is the width of the wave-breaking chamber, d is the water depth, L is the wavelength of the incident wave, ξ is the porosity of the filling gravel, and γ is the slope of the gravel slope;

[0066] The coefficient of determination R of the calculation formula fitted by the least squares method in this embodiment is 2 =0.833, which meets the correlation requirements of the multivariate nonlinear fitting equation;

[0067] The comparison between the calculated value of the reflection coefficient obtained by the calculation formula and the experimental value of the reflection coefficient is as follows: Figure 7 As shown, the calculated value of the reflection coefficient obtained by the calculation formula is compared with the experimental value of the reflection coefficient obtained by the physical model in the prior art. Figure 8 As shown, Figure 7 and Figure 8 The scattered data are all calculated values ​​of the reflection coefficient obtained by the calculation formula. The horizontal axis is the experimental value Kr of the reflection coefficient obtained by the physical model, and the vertical axis is the calculated value Kr of the reflection coefficient obtained by the calculation formula. * , the solid line is y=x, and the two dotted lines are y=x+0.1 and y=x-0.1. Figure 7 and Figure 8 It can be seen that the calculated value of the reflection coefficient Kr * They are evenly distributed on both sides of y=x and within the envelope of y=x±0.1, indicating that the calculated value of the reflection coefficient Kr *It is in good agreement with the experimental value Kr, indicating that the calculation formula is more effective in calculating the reflection coefficient of the open caisson with a gravel slope inside.

[0068] Example 2

[0069] A computer-readable storage medium stores a computer program and can be read and executed by a processor. When the computer program is executed by the processor, the method for calculating the reflection coefficient of the perforated caisson as described in Example 1 is implemented.

Claims

1. A method for calculating the reflection coefficient of an open-hole caisson, characterized in that: Obtain the width B of the wave-breaking chamber of the perforated caisson in the project, the porosity ξ of the gravel filled inside the perforated caisson, the slope γ of the gravel slope inside the perforated caisson, the water depth d of the environment where the perforated caisson is located, and the wavelength L of the incident wave in the environment where the perforated caisson is located. Then, the reflection coefficient K of the perforated caisson with a gravel slope inside the project is obtained by the following formula: r :

2. The method for calculating the reflection coefficient of a perforated caisson according to claim 1, characterized in that: The reflection coefficient K r The applicable range of each parameter in the calculation formula is: relative to the width of the wave-breaking chamber Relative water depth The porosity of the filled gravel is ξ=0.25-0.50, the slope of the gravel slope is γ=0.5-1.0, and the reflection coefficient K r The calculation formula is applicable to the following ranges of incident wave height H, wave period T and water depth d: incident wave height H = 1 ~ 2m, incident wave period T = 3.58 ~ 10.29s, water depth d = 8 ~ 10m.

3. The method for calculating the reflection coefficient of a perforated caisson according to claim 1, characterized in that: The reflection coefficient K r The calculation formula is obtained through the following steps: S1. Establish a physical model of an open caisson with a gravel slope inside; S2. Using the physical model established in S1, multiple model tests are conducted to obtain multiple test values ​​of reflection coefficients. The slope γ of the gravel slope, the porosity ξ of the filled gravel, the wave height H of the incident wave, the wave period T of the incident wave, or the water depth d of each model test are different. S3, based on the test values ​​of multiple groups of reflection coefficients obtained in S2, the reflection coefficient K is obtained by least squares fitting. r The calculation formula for .

4. The method for calculating the reflection coefficient of a perforated caisson according to claim 3, characterized in that: The physical model of the open caisson with a gravel slope inside in S1 includes the following steps: S11. Make a model of an open-hole caisson, the model having a wave-breaking chamber, arrange a wave maker and the model at both ends of the water tank, and provide three wave height meters equidistantly arranged in front of the model; S12, filling gravel in the wave-breaking chamber of the model made in S11, the gravel forming a gravel slope in the wave-breaking chamber, and obtaining the slope of the gravel slope and the porosity of the filled gravel; S13, filling water into the water tank, and after the water filling is completed, obtaining the water depth in front of the model; S14, starting a wave maker to generate incident waves in the water tank, and obtaining wave information of the incident waves.

5. The method for calculating the reflection coefficient of a perforated caisson according to claim 4, characterized in that: The space in the model in S11 is divided into a front cabin and a rear cabin by a partition wall. The front cabin is a wave-breaking chamber, and a through hole is provided at the front end of the front cabin for waves to flow in.

6. The method for calculating the reflection coefficient of a perforated caisson according to claim 4, characterized in that: The distance between the wave height meter in S11 and the model is greater than or equal to 0.2L, and the distance between two adjacent wave height meters is 0.05L to 0.45L, where L is the wavelength of the incident wave.

7. The method for calculating the reflection coefficient of a perforated caisson according to claim 4, characterized in that: The porosity of the packed gravel in S12 is obtained by the following formula: Where: ξ is the porosity of the filled gravel, V1 is the total volume of the slope part filled with gravel, M3 is the total mass of the filled gravel in the slope part, and ρ3 is the density of the gravel filled in the slope part.

8. The method for calculating the reflection coefficient of a perforated caisson according to claim 4, characterized in that: The wave information of the incident wave in S14 includes the wave height of the incident wave, the wavelength of the incident wave and the wave period of the incident wave.

9. The method for calculating the reflection coefficient of a perforated caisson according to claim 3, characterized in that: The step of obtaining the test value of the reflection coefficient in S2 comprises the following steps: S21, obtaining test results of three wave height meters in each model test; S22. Based on the test results of the wave height meter obtained in S21, the Gado two-point method is used to separate the incident wave and the reflected wave, so as to calculate the test value of the reflection coefficient of each physical model test.

10. A computer-readable storage medium storing a computer program and capable of being read and executed by a processor, characterized in that: When the computer program is executed by a processor, the method for calculating the reflection coefficient of a perforated caisson according to any one of claims 1 to 9 is implemented.

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