Method for rapidly optimizing wave absorbing performance of underwater ecological submerged dike

Abstract

The invention discloses a method for rapidly optimizing the wave absorption performance of an underwater ecological submerged dike, and belongs to the technical field of ocean engineering, and the method comprises the following steps: taking an oyster reef as a research object, comprehensively considering marine environment factors and ecological submerged reef arrangement which influence the wave absorption performance of the ecological submerged reef, carrying out dimensionless processing, and determining seven independent variable parameters: relative water depth, water depth, water depth, water depth and water depth; the wave steep, the relative immersion depth of the oyster reefs, the relative length of the oyster reefs, the relative distance between the oyster reefs, the riverbed gradient and the number of the oyster reefs are determined. According to the method, nonlinear influences between all variable parameters are considered, a second-order optimal design model is suggested, an information matrix representing how changes of all factors affect variances and covariances of model parameters is calculated, and an optimal design scheme is obtained by maximizing eigenvalues of an inverse matrix. Compared with the traditional full-factor test design, the method has the advantages that the number of design groups is reduced on the premise of ensuring that the test combination is as comprehensive as possible, and the time of physical model experiment and numerical simulation calculation is greatly shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of ocean engineering, coastal protection and ecological restoration technologies, and particularly relates to a method for rapidly optimizing the wave dissipation performance of underwater ecological submerged breakwaters. Background Art

[0002] Oyster reefs, as part of ecosystem engineering, are widely distributed in temperate and subtropical estuaries and shallow sea areas. These coral reefs have made significant contributions to water purification, enhancement of fish resources, mitigation of coastline erosion, carbon sequestration, enhancement of biodiversity and overall ecosystem stability. They play a crucial role in stabilizing intertidal sediments and influencing hydrodynamic patterns in the coastal environment.

[0003] With the intensification of global climate change and human activities, problems such as coastal erosion and sea-level rise have become increasingly serious, posing higher requirements for coastal protection projects. Traditional rigid protection structures (such as concrete dams) can effectively resist wave erosion, but have negative impacts on the ecological environment. In recent years, nature-based protection structures (such as oyster reefs, coral reefs, etc.) have gradually received attention because they can not only dissipate wave energy, but also promote biodiversity, improve water quality and restore ecosystems.

[0004] However, the design and optimization of ecological submerged breakwaters face many challenges: 1. Complex influencing factors: The wave dissipation performance is affected by various marine environmental factors (such as water depth, wave steepness, slope) and the parameters of the ecological submerged breakwater itself (such as reef body size, spacing, number), and there are non-linear interactions between these factors.

[0005] 2. High experimental cost: Traditional full-factor experimental designs require a large number of experimental runs, resulting in high time and economic costs.

[0006] 3. Insufficient design accuracy: Traditional methods rely on empirical formulas and simplified models, and it is difficult to accurately describe complex underwater environments and non-linear relationships. Summary of the Invention

[0007] The object of the present invention is to provide a method for rapidly optimizing the wave dissipation performance of underwater ecological submerged breakwaters, and a method for optimizing the wave dissipation performance of underwater ecological submerged breakwaters based on D-optimal design is proposed. As an efficient experimental design method, D-optimal design can significantly reduce the number of experiments by optimizing the selection of experimental points, and at the same time improve the accuracy of parameter estimation. Based on D-optimal design, the present invention proposes a method for rapidly optimizing the wave dissipation performance of underwater ecological submerged breakwaters, and reduces the original 2,400,000 experimental combinations to 1244 under the premise of ensuring high precision.

[0008] To achieve the above object, the present invention provides a method for quickly optimizing the wave dissipation performance of an underwater ecological submerged breakwater, comprising the following steps: Step S1: Select oyster reefs as the underwater ecological breakwater, consider the marine environmental factors and ecological reef layout factors that affect the wave dissipation performance of the ecological submerged reef, and perform corresponding dimensionless processing to obtain independent variable factors; Step S2: Take the independent variable factors in Step S1 as the experimental independent variables, and take the transmission coefficient of the wave passing through the oyster reef as the response value, and establish a fitting model based on D-optimal design between the experimental independent variables and the response value; Step S3: Use the fitting model to establish a design matrix, calculate the information matrix representing the variances and covariances of how the changes in each factor affect the model parameters, maximize the eigenvalues of the inverse matrix, take the transmission coefficient as the minimum value, and comprehensively consider the economic benefits to optimize the experimental scheme to obtain the experimental combination when the transmission coefficient is the smallest.

[0009] Preferably, the specific content in Step S1 is as follows: Determine that the factors affecting the wave dissipation performance of artificial reefs are divided into marine environmental factors including the incoming wave height , wavelength , period , riverbed slope and water depth , and ecological submerged reef layout factors including oyster reef height , oyster reef length , the spacing between oyster reefs and the number of oyster reefs ; Perform dimensionless processing on the above marine environmental factors and ecological submerged reef layout factors to obtain 7 independent variable factors, including relative water depth , wave steepness , relative immersion depth of oyster reef , relative length of oyster reef , relative length of oyster reef spacing , slope and the number of oyster reefs , and the specific processing process is as follows: Relative water depth , definition: Relative water depth is the ratio of water depth h to wavelength L, represented by the dimensionless parameter kh, where is the wave number, and the formula is as follows: ; Wave steepness is defined as: Wave steepness is the ratio of wave height H to wavelength L , usually represented by the dimensionless parameter kH / 2, and the formula is as follows: ; Definition of relative immersion depth of oyster reef The relative immersion depth of oyster reef is the ratio of the height of the oyster reef to the water depth , and the formula is as follows: ; Definition of relative length of oyster reef The relative length of oyster reef is the ratio of the length of the oyster reef to the wavelength , usually represented by the dimensionless parameter , and the formula is as follows: ; Definition of relative length of oyster reef spacing The relative distance between oyster reefs is the ratio of the reef spacing to the wavelength , represented by the dimensionless parameter , and the formula is as follows: ; Definition of slope The riverbed slope is the ratio of the change in riverbed height to the horizontal distance, represented by the dimensionless parameter , and the formula is as follows: ; Definition of the number of oyster reefs The number of oyster reefs is the total number of reefs arranged in the test area, usually represented by the dimensionless parameter N.

[0010] Preferably, the specific steps of step S2 are as follows: Taking the 7 independent variable factors obtained in step S1 as the test independent variables, first, considering the influence of each of the seven variables on the wave dissipation performance, the linear term term is obtained, where is the coefficient, determined according to the contribution value. Secondly, in order to make the fitted model more accurate, the quadratic term of the independent variable is given. In addition, due to the interaction between the independent variables, the interaction term of the variables needs to be considered, and the interaction term is ; In summary, the formula for establishing the fitting model of the test independent variable and the response value based on the D-optimal design is as follows: ; In the above formula, is the wave dissipation performance of the oyster reef, is the offset, is the linear offset coefficient, is the second-order offset coefficient, is the interaction effect coefficient, , is the th influence factor.

[0011] Preferably, in the step S3, the process of establishing the design matrix is as follows: All combinations of the experiment are obtained according to the full factorial method as candidate points for the D-optimal design method, and then the fitting model of S2 is used to calculate the design matrix P ( n ╳ p ). Each row of the design matrix represents an experimental point; each column of the design matrix represents a model term including an intercept, a linear term, a second-order term, and an interaction term.

[0012] Preferably, in the step S3, the information matrix is calculated using the design matrix, specifically as follows: ; where P T is the transpose matrix of the design matrix P The calculation method is: ; Each element of M is the dot product between the columns of P; Calculate its determinant |M|. The design goal of the D-optimal design is to maximize the determinant of the information matrix. By exchanging the experimental points, different values of the determinant of the information matrix are obtained by changing the design matrix, and this iteration is performed until the design matrix corresponding to the maximum determinant is found, and the optimal combination of experimental points is obtained.

[0013] Therefore, the present invention adopts the above method for quickly optimizing the wave dissipation performance of an underwater ecological submerged breakwater, and has the following advantages: High efficiency: The number of experiments is significantly reduced by the D-optimal design, which can be reduced to five ten-thousandths of the original, thus greatly shortening the design cycle.

[0014] Economy: Reduce the consumption of experimental resources and lower the design cost.

[0015] Accuracy: The non-linear relationship between various factors is accurately described by the second-order mathematical model, improving the design accuracy.

[0016] Environmental protection: The design based on the natural ecology of oyster reefs helps ecological protection and sustainable development.

[0017] Universality: This method is not only applicable to oyster reefs, but can also be extended to the design of other types of ecological submerged breakwaters; it is not only valid in the laboratory, but also applicable in the open sea.

[0018] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0019] Figure 1 It is a simplified model diagram of the test process in a method for quickly optimizing the wave dissipation performance of an underwater ecological submerged breakwater according to the present invention; Figure 2 It is a comparison diagram of the effects of the full factor test method and the test method proposed by the present invention in a method for quickly optimizing the wave dissipation performance of an underwater ecological submerged breakwater according to the present invention. Specific embodiments

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. The specific model specifications need to be selected and determined according to the actual specifications of the device, etc. The specific selection calculation method adopts the existing technology in the art, so it will not be elaborated in detail here.

[0021] Embodiment As Figure 1 - Figure 2 shown, the present invention provides a method for quickly optimizing the wave dissipation performance of an underwater ecological submerged breakwater, including the following steps: S1: Select oyster reefs as the underwater ecological breakwater, consider the marine environmental factors and ecological submerged reef layout factors that affect the wave dissipation performance of the ecological submerged reef, and perform corresponding dimensionless processing to obtain independent variable factors, specifically as follows: Determine that the factors affecting the wave dissipation performance of artificial island reefs are divided into marine environmental factors including incoming wave height , wavelength , period , riverbed slope and water depth , and ecological submerged reef layout factors including oyster reef height , oyster reef length , the spacing between oyster reefs and the number of oyster reefs ; Perform dimensionless processing on the above marine environmental factors and ecological submerged reef layout factors to obtain 7 independent variable factors, including relative water depth , wave steepness , relative immersion depth of oyster reefs , relative length of oyster reefs , relative length of the spacing between oyster reefs , slope and the number of oyster reefs , and determine the levels of each factor, which are used as independent variable factors affecting the wave dissipation performance of oyster reefs. Dimensionless treatment can not only reduce the number of independent variables, but also make the research results applicable in environments different from the laboratory. The specific process is as follows: Relative water depth , defined as: relative water depth is the ratio of water depth h to wavelength L, represented by the dimensionless parameter kh, where is the wave number, and the formula is as follows: ; Physical meaning: Relative water depth reflects the influence of water depth on wave characteristics during wave propagation. When kh is small, the wave is significantly affected by water depth (shallow water area); when kh is large, the wave is less affected by water depth (deep water area).

[0022] Wave steepness is defined as: wave steepness is the ratio of wave height H to wavelength L , usually represented by the dimensionless parameter kH / 2, and the formula is as follows: ; Physical meaning: Wave steepness reflects the steepness of the wave and is an important indicator of wave breaking. The larger the wave steepness, the easier the wave is to break.

[0023] Relative immersion depth of oyster reef is defined as: relative immersion depth of oyster reef is the ratio of oyster reef height d to water depth h, and the formula is as follows: ; Physical meaning: This parameter reflects the position of the oyster reef in the water body and affects the interaction between the wave and the reef body. When is small, the influence of the reef body on the wave is small; when is large, the wave dissipation effect of the reef body is significant.

[0024] Relative length of oyster reef is defined as: relative length of oyster reef is the ratio of oyster reef length to wavelength , usually represented by the dimensionless parameter , and the formula is as follows: ; Physical meaning: This parameter reflects the proportional relationship between the oyster reef length and the wavelength and affects the interaction range between the wave and the reef body.

[0025] Relative length of oyster reef spacing is defined as: relative distance between oyster reefs is the ratio of reef spacing to wavelength , using the dimensionless parameter It is expressed as follows: ; Physical meaning: This parameter reflects the proportional relationship between the spacing between reef bodies and the wavelength, and affects the propagation and attenuation effects of waves between reef bodies.

[0026] Slope Definition: The riverbed slope is the ratio of the change in riverbed height to the horizontal distance, and is expressed using the dimensionless parameter It is expressed as follows: ; Physical meaning: The riverbed slope affects the propagation and reflection characteristics of waves. The larger the slope, the more significant the wave deformation and energy loss.

[0027] Number of oyster reefs Definition: The number of oyster reefs is the total number of reef bodies arranged in the test area, usually expressed using the dimensionless parameter It is expressed as follows: The number of reef bodies directly affects the attenuation effect of waves. The more the number, the greater the wave energy loss, but the higher the layout cost.

[0028] In this embodiment, the specific values of the above independent variable factors are as follows: Relative water depth (kh), the number of levels is 10, and the value range is [0.5, 1]; Wave steepness (kH / 2), the number of levels is 10, and the value range is [0.012, 0.030]; Slope (s), the number of levels is 6, and the value range is [0, 1:400]; The self - factors of the oyster reef include: Relative length of the oyster reef (kLr / (2π)), the number of levels is 10, and the value range is [0.22, 0.40]; Relative height of the oyster reef (d / h), the number of levels is 10, and the value range is [0.1, 0.7]; Relative length of the oyster reef spacing (kLs / (2π)), the number of levels is 10, and the value range is [0.11, 0.2]; Number of oyster reefs (N), the number of levels is 4, and the value range is [1, 4].

[0029] The value ranges of the above independent variable factors are sorted out in Table 1 as follows: Table 1: ; S2: Taking the independent variable factors in step S1 as the test independent variables and the transmission coefficient of waves passing through the oyster reef as the response value, establish a fitting model based on D - optimal design for the test independent variables and the response value, specifically as follows: Take the seven independent variable factors obtained in step S1 as the experimental independent variables. First, considering the influence of each of the seven variables on the wave-dissipating performance, the linear terms are obtained, where is the coefficient, determined according to the contribution value. Second, in order to make the fitted model more accurate, the quadratic terms of the independent variables are given. In addition, due to the interaction between the independent variables, the interaction terms of the variables need to be considered, and the interaction terms are . In summary, the formula for establishing the fitted model of the experimental independent variables and the response value based on the D-optimal design is as follows: ; In the above formula, is the wave-dissipating performance of the oyster reef, is the offset, is the linear offset coefficient, is the second-order offset coefficient, is the interaction effect coefficient, , are the th, st influencing factors.

[0030] S3: Use the fitted model to establish the design matrix. According to the full factorial method, all combinations of the experiments are obtained as the candidate points of the D-optimal design method. Then, use the fitted model in S2 to calculate the design matrix P ( n ╳ p ). Each row of the design matrix represents an experimental point; each column of the design matrix represents a model term including the intercept, linear term, second-order term, and interaction term.

[0031] Use the design matrix to calculate the information matrix, specifically as follows: ; where P T is the transpose matrix of the design matrix P The calculation method is: ; Each element of M is the dot product between the columns of P; Calculate its determinant |M|. The design goal of the D-optimal design is to maximize the determinant of the information matrix. Exchange the experimental points to change the design matrix and obtain the values of the determinants of different information matrices, and iterate until the design matrix corresponding to the maximum determinant is found, and the optimal combination of experimental points is obtained.

[0032] By calculating the information matrix that characterizes how the changes in various factors affect the variance and covariance of the model parameters, by maximizing the eigenvalues of the inverse matrix, taking the transmission coefficient as the minimum value, and comprehensively considering the economic benefits, the experimental scheme is optimized to obtain the experimental combination when the transmission coefficient is the smallest.

[0033] The technical solution of this application is compared with the existing full-factor experiment, and the comparison process is as shown in Table 2 below: Table 2 ;

[0034] After testing, the results of counting the number of experimental groups are as Figure 2 shown, indicating that the technical solution of the present invention can effectively reduce the number of experimental groups.

[0035] Therefore, the present invention adopts a method for quickly optimizing the wave-dissipating performance of an underwater ecological submerged breakwater. By comprehensively considering marine environmental factors and the layout parameters of the ecological submerged breakwater, using a mathematical model and an optimization algorithm, the number of experiments is significantly reduced (reduced to five ten-thousandths of the original in this example), the design efficiency and accuracy are improved, and it is applicable to the design and optimization of ecological submerged breakwaters such as oyster reefs.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solution of the present invention, and these modifications or equivalent replacements cannot make the modified technical solution deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for rapidly optimizing the wave-breaking performance of an underwater ecological submerged dike, characterized in that: The following steps are involved: Step S1: Select oyster reef as underwater ecological dam, consider the marine environmental factors and ecological reef layout factors that affect the wave-breaking performance of ecological reefs, and perform corresponding dimensionless processing to obtain independent variable factors; Step S2: taking the independent variable factors of step S1 as the experimental independent variables and the transmission coefficient of the wave passing through the oyster reef as the response value, and establishing a fitting model of the experimental independent variables and the response value based on D-optimal design; Step S3: Use the fitting model to establish a design matrix, calculate the information matrix that characterizes how changes in various factors affect the variance and covariance of model parameters, maximize the eigenvalue of the inverse matrix, take the transmission coefficient as the minimum, and comprehensively consider the economic benefits to optimize the test plan and obtain the test combination with the minimum transmission coefficient.

2. A method for rapidly optimizing the wave-breaking performance of an underwater ecological submerged dike according to claim 1, characterized in that: The details of step S1 are as follows: The factors that affect the wave-breaking performance of artificial islands and reefs are divided into marine environmental factors, including wave height, ,wavelength ,cycle , riverbed slope and water depth , ecological reef layout factors include oyster reef height , oyster reef length , spacing between oyster reefs , and the number of oyster reefs ; The above-mentioned marine environmental factors and ecological reef layout factors were processed dimensionlessly to obtain 7 independent variable factors, including relative water depth , steep , relative immersion depth of oyster reef , the relative length of the oyster reef , the relative length of the oyster reef spacing ,slope and the number of oyster reefs The specific process of the processing is as follows: Relative water depth , Definition: Relative water depth is the ratio of water depth h to wavelength L, expressed by dimensionless parameter kh, where is the wave number, and the formula is as follows: ； Steep Definition: Wave steepness is the wave height H With wavelength L The ratio is usually expressed as a dimensionless parameter kH / 2, and the formula is as follows: ； Relative immersion depth of oyster reefs Definition: The relative submergence depth of an oyster reef is the height of the oyster reef. With water depth The ratio of is as follows: ； Relative length of oyster reefs Definition: The relative length of an oyster reef is the length of the oyster reef. With wavelength The ratio of The formula is as follows: ； Relative length of oyster reef spacing Definition: The relative distance between oyster reefs is the distance between reefs. With wavelength The ratio of , using dimensionless parameters The formula is as follows: ； slope Definition: The riverbed slope is the ratio of the change in riverbed height to the horizontal distance, using the dimensionless parameter The formula is as follows: ； Number of oyster reefs According to the definition, the number of oyster reefs is the total number of reefs arranged in the experimental area, usually represented by the dimensionless parameter N.

3. A method for rapidly optimizing the wave-breaking performance of an underwater ecological submerged dike according to claim 2, characterized in that: The step S2 is specifically as follows: The seven independent variable factors obtained in step S1 are used as experimental independent variables. First, considering the influence of each of the seven variables on the wave-breaking performance, the linear term Item, among which is the coefficient, which is determined according to the contribution value. Secondly, in order to make the fitted model more accurate, the quadratic term of the independent variable is given. In addition, since there are interactions between the variables, the interaction of the variables needs to be considered. The interaction term is ; In summary, the formula for establishing the fitting model based on D-optimal design of experimental independent variables and response values ​​is as follows: ； In the above formula, For the wave-breaking performance of oyster reefs, is the offset, is the linear shift coefficient, is the second-order offset coefficient, is the interaction effect coefficient, , For the , No. An influencing factor.

4. A method for rapidly optimizing the wave-breaking performance of an underwater ecological submerged dike according to claim 3, characterized in that: In step S3, the process of establishing the design matrix is ​​as follows: According to the full factorial method, all combinations of experiments are obtained as candidate points for the D-optimal design method, and then the design matrix P ( n ╳ p ), each row of the design matrix represents an experimental point; each column of the design matrix represents a model term including intercept, linear term, second-order term, and interaction term.

5. A method for rapidly optimizing the wave-breaking performance of an underwater ecological submerged dike according to claim 4, characterized in that: In step S3, the information matrix is ​​calculated using the design matrix, as follows: ； Among them, P T is the transposed matrix of the design matrix P The calculation method is: ； Each element of M is the dot product between the columns of P; Calculate its determinant |M|, the design goal of D-optimal design is to maximize the determinant of the information matrix, exchange the experimental points to change the design matrix, calculate and obtain different values ​​of the determinant of the information matrix, and iterate until the design matrix corresponding to the largest determinant is found to obtain the optimal combination of experimental points.

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