A method for quickly optimizing the wave dissipation performance of underwater ecological submerged dikes

Abstract

The present invention discloses a method for rapidly optimizing the wave dissipation performance of an underwater ecological submerged breakwater, belonging to the technical field of ocean engineering, and comprising the following steps: taking oyster reefs as the research object, comprehensively considering the marine environmental factors and the layout of ecological submerged reefs that affect the wave dissipation performance of ecological submerged reefs, and performing dimensionless processing to determine 7 independent variable parameters: relative water depth, wave steepness, relative immersion depth of oyster reefs, relative length of oyster reefs, relative distance between oyster reefs, riverbed slope, and the number of oyster reefs. Considering the non-linear influence between the independent variable parameters, a second-order optimal design model is proposed, the information matrix of variance and covariance characterizing how the changes of each factor affect the model parameters is calculated, and the optimal design scheme is obtained by maximizing the eigenvalue of the inverse matrix. Compared with the traditional full-factor experimental design, the present invention reduces the number of design groups on the premise of ensuring that the experimental combinations are as comprehensive as possible, and greatly reduces the time of physical model experiments and numerical simulation calculations.

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 make 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:

[0005] 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.

[0006] 2. High test cost: Traditional full-factor experimental designs require a large number of test runs, resulting in high time and economic costs.

[0007] 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

[0008] The purpose 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 tests by optimizing the selection of test 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. On the premise of ensuring high precision, the original 2,400,000 test combinations are reduced to 1244.

[0009] 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:

[0010] 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;

[0011] Step S2: Take the independent variable factors in Step S1 as the test independent variables, and the transmission coefficient of waves through the oyster reef as the response value, and establish a fitting model based on D-optimal design between the test independent variables and the response value;

[0012] Step S3: Use the fitting model to establish a design matrix, calculate the information matrix representing the variance and covariance of how each factor change affects the model parameters, maximize the eigenvalue of the inverse matrix, take the transmission coefficient as the minimum value, and comprehensively consider the economic benefits to optimize the test scheme to obtain the test combination when the transmission coefficient is the minimum.

[0013] Preferably, the specific content in Step S1 is as follows:

[0014] Determine that the factors affecting the wave dissipation performance of artificial reefs are divided into marine environmental factors including incoming wave height , wavelength , period , riverbed slope and water depth , and ecological reef layout factors including oyster reef height , oyster reef length , the spacing between oyster reefs and the number of oyster reefs ;

[0015] Perform dimensionless processing on the above marine environmental factors and ecological reef layout factors to obtain 7 independent variable factors, including relative water depth , wave steepness , relative submerged 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 the specific processing process is as follows:

[0016] 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:

[0017] ;

[0018] Steep waves Definition: Wave steepness is the wave height H and wavelength L The ratio is usually expressed as a dimensionless parameter kH / 2, and the formula is as follows:

[0019] ;

[0020] Relative immersion depth of oyster reefs Definition: The relative submerged depth of an oyster reef is the height of the oyster reef and water depth The ratio is as follows:

[0021] ;

[0022] Relative length of oyster reefs Definition: The relative length of an oyster reef is the length of the oyster reef and wavelength The ratio of , usually expressed as a dimensionless parameter The formula is as follows:

[0023] ;

[0024] Relative length of oyster reef spacing Definition: The relative distance between oyster reefs is the distance between reefs and wavelength The ratio of , using dimensionless parameters The formula is as follows:

[0025] ;

[0026] slope Definition: Riverbed slope is the ratio of the change in riverbed height to the horizontal distance, using the dimensionless parameter The formula is as follows:

[0027] ;

[0028] Number of oyster reefs According to the definition of , the number of oyster reefs is the total number of reefs arranged in the experimental area, usually represented by the dimensionless parameter N.

[0029] Preferably, the step S2 is specifically as follows:

[0030] The 7 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 elimination performance, the linear term is obtained. Item, among which is a 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, since there are interactions between the independent variables, the interaction of the variables needs to be considered, and the interaction term is ; In summary, the formula for establishing the fitted model of the experimental independent variable and the response value based on the D-optimal design is as follows:

[0031] ;

[0032] 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, , is the th, th influencing factor.

[0033] Preferably, in the step S3, the process of establishing the design matrix is specifically as follows:

[0034] 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 design matrix P ( n ╳ p ) is calculated using the fitted model in S2. 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.

[0035] Preferably, in the step S3, the information matrix is calculated using the design matrix, specifically as follows:

[0036] ;

[0037] where P T is the transpose matrix of the design matrix P

[0038] The calculation method is:

[0039] ;

[0040] Each element of M is the dot product between the columns of P;

[0041] 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.

[0042] Therefore, the present invention adopts the above method for quickly optimizing the wave-dissipating performance of an underwater ecological submerged breakwater, which has the following advantages:

[0043] High efficiency: By using the D-optimal design, the number of tests is significantly reduced, which can be reduced to five ten-thousandths of the original, thus greatly shortening the design cycle.

[0044] Economy: Reduce the consumption of test resources and lower the design cost.

[0045] Accuracy: Accurately describe the non-linear relationship between various factors through a second-order mathematical model, improving the design accuracy.

[0046] Environmental protection: The design based on natural ecological oyster reefs helps with ecological protection and sustainable development.

[0047] 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 laboratory conclusions but also applicable in the open sea.

[0048] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a simplified model diagram of the test process in a method for quickly optimizing the wave-dissipating performance of an underwater ecological submerged breakwater according to the present invention;

[0050] 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-dissipating performance of an underwater ecological submerged breakwater according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] 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 in conjunction with the 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 according to the actual specifications of the device, etc. The specific selection calculation method adopts the existing technology in the field, so it will not be elaborated in detail.

[0052] Embodiment

[0053] As Figure 1 - Figure 2 shown, the present invention provides a method for quickly optimizing the wave-dissipating performance of an underwater ecological submerged breakwater, including the following steps:

[0054] S1: Select oyster reefs as underwater ecological dikes. Consider the marine environmental factors and ecological reef layout factors that affect the wave-dissipating performance of ecological reefs, and perform corresponding dimensionless processing to obtain independent variable factors, as follows:

[0055] Determine that the factors affecting the wave-dissipating performance of artificial reefs are divided into marine environmental factors, including the incoming wave height , wavelength , period , riverbed slope and water depth , and ecological reef layout factors, including oyster reef height , oyster reef length , the spacing between oyster reefs and the number of oyster reefs ;

[0056] Perform dimensionless processing on the above marine environmental factors and ecological 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 level numbers of each factor as independent variable factors affecting the wave-dissipating performance of oyster reefs. Dimensionless processing 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:

[0057] 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:

[0058] ;

[0059] 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).

[0060] Wave steepness , definition: 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:

[0061] ;

[0062] Physical meaning: The wave steepness reflects the steepness of the wave and is an important indicator of wave breaking. The greater the wave steepness, the easier the wave is to break.

[0063] Relative submergence depth of oyster reef Definition: The relative submergence depth of oyster reef is the ratio of the oyster reef height d to the water depth h, and the formula is as follows:

[0064] ;

[0065] 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 attenuation effect of the reef body is significant.

[0066] Relative length of oyster reef Definition: The relative length of oyster reef is the ratio of the oyster reef length to the wavelength and is usually represented by the dimensionless parameter The formula is as follows:

[0067] ;

[0068] 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.

[0069] Relative length of oyster reef spacing Definition: The relative distance between oyster reefs is the ratio of the reef spacing to the wavelength and is represented by the dimensionless parameter The formula is as follows:

[0070] ;

[0071] Physical meaning: This parameter reflects the proportional relationship between the spacing between reef bodies and the wavelength and affects the propagation and attenuation effect of waves between reef bodies.

[0072] Slope Definition: The riverbed slope is the ratio of the change in riverbed height to the horizontal distance and is represented by the dimensionless parameter The formula is as follows:

[0073] ;

[0074] Physical meaning: The riverbed slope affects the propagation and reflection characteristics of waves. The greater the slope, the more significant the wave deformation and energy loss.

[0075] Number of oyster reefs By definition, the number of oyster reefs is the total number of reef bodies arranged within the test area, usually represented by the dimensionless parameter The number of reef bodies directly affects the wave attenuation effect. The more the number, the greater the wave energy loss, but the higher the layout cost.

[0076] In this embodiment, the specific values of the above independent variable factors are as follows:

[0077] Relative water depth (kh), with 10 levels, and the value range is [0.5, 1];

[0078] Wave steepness (kH / 2), with 10 levels, and the value range is [0.012, 0.030];

[0079] Slope (s), with 6 levels, and the value range is [0, 1:400];

[0080] The self - factors of the oyster reef include:

[0081] Relative length of the oyster reef (kLr / (2𝜋)), with 10 levels, and the value range is [0.22, 0.40];

[0082] Relative height of the oyster reef (d / h), with 10 levels, and the value range is [0.1, 0.7];

[0083] Relative length of the oyster reef spacing (kLs / (2𝜋)), with 10 levels, and the value range is [0.11, 0.2];

[0084] Number of oyster reefs (N), with 4 levels, and the value range is [1, 4].

[0085] The value ranges of the above independent variable factors are sorted out in Table 1 below:

[0086] Table 1:

[0087] ;

[0088] S2: Taking the independent variable factors in step S1 as the test independent variables and the transmission coefficient of waves 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:

[0089] 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 - damping performance, the linear terms terms are obtained, where is the coefficient, determined according to the contribution value. Secondly, in order to make the fitted model more accurate, the quadratic terms of the independent variables are given In addition, due to the interaction among independent variables, the interaction of variables needs to be considered, and the interaction term is ; In summary, the formula for establishing the fitting model of the independent variables and response values of the experiment based on D-optimal design is as follows:

[0090] ;

[0091] In the above formula, is the wave-dissipating performance of oyster reefs, is the offset, is the linear offset coefficient, is the second-order offset coefficient, is the interaction effect coefficient, [[ID=CH=21]]and are the th, th influencing factors.

[0092] S3: Use the fitting model to establish the design matrix. According to the full factorial method, all combinations of the experiment are obtained as candidate points for the D-optimal design method. Then, use the fitting 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 intercept, linear term, second-order term, and interaction term.

[0093] Calculate the information matrix using the design matrix, specifically as follows:

[0094] ;

[0095] where P T is the transpose matrix of the design matrix P

[0096] The calculation method is:

[0097] ;

[0098] Each element of M is the dot product between columns of P;

[0099] 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. Iterate in this way until the design matrix corresponding to the maximum determinant is found, and the optimal combination of experimental points is obtained.

[0100] By calculating the information matrix that characterizes how the changes of various factors affect the variances and covariances 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, optimize the experimental scheme to obtain the experimental combination when the transmission coefficient is the smallest.

[0101] Compare the technical solution of this application with the existing full-factorial experiment. The comparison process is shown in Table 2 below:

[0102] Table 2

[0103] ;

[0104] After the test, the result of counting the number of experimental groups is as Figure 2 shown, indicating that the technical solution of the present invention can effectively reduce the number of experimental groups.

[0105] Therefore, the present invention adopts a method for quickly optimizing the wave-dissipating performance of underwater ecological submerged dikes. By comprehensively considering marine environmental factors and ecological submerged dike layout parameters, using mathematical models and optimization algorithms, the number of experiments is significantly reduced (reduced to five ten-thousandths of the original in this example), improving the design efficiency and accuracy, and is applicable to the design and optimization of ecological submerged dikes such as oyster reefs.

[0106] 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 the technical solution of the present invention or make equivalent replacements, and these modifications or equivalent replacements do not enable the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for quickly optimizing the wave dissipation performance of an underwater ecological submerged dike, characterized in that: It includes the following steps: Step S1: Select oyster reefs as underwater ecological submerged breakwaters, consider the marine environmental factors and ecological submerged breakwater layout factors that affect the wave dissipation performance of underwater ecological submerged breakwaters, and perform corresponding dimensionless processing to obtain independent variable factors; The factors determining the wave dissipation performance of underwater ecological submerged breakwaters are divided into marine environmental factors including incident wave height , wavelength , period , riverbed slope , and water depth , and underwater ecological submerged breakwater layout factors including oyster reef height , oyster reef length , the spacing between oyster reefs , and the number of oyster reefs ; The above marine environmental factors and underwater ecological submerged breakwater layout factors are made dimensionless 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 ; Step S2: Take the independent variable factors in Step S1 as the experimental independent variables, and the transmission coefficient of waves passing through oyster reefs as the response value, and establish a fitting model based on D-optimal design between the experimental independent variables and the response value; Taking the seven independent variable factors obtained in step S1 as the experimental independent variables, first, considering the influence of each of the seven independent variables on the wave dissipation performance, the linear terms are obtained , where is the linear offset coefficient, determined according to the contribution value. Secondly, in order to make the fitted model more accurate, the quadratic terms of the independent variables are given . In addition, since there are interactions between the independent variables, the interaction terms of the variables need to be considered, and the interaction term is ; In summary, the formula for establishing the fitting 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 oyster reefs, is the offset, is the linear offset coefficient, is the second-order offset coefficient, is the interaction effect coefficient, and are the th and th influencing factors; Step S3: Use the fitting model to establish a design matrix, calculate the information matrix that characterizes how the changes in each factor affect the variance and covariance of the model parameters, maximize the eigenvalue of the inverse matrix, take the transmission coefficient as the minimum value, and comprehensively consider economic benefits to optimize the experimental scheme to obtain the experimental combination when the transmission coefficient is the minimum.

2. A method for rapidly optimizing the wave dissipation performance of an underwater ecological submerged dike according to claim 1, characterized in that: The specific process of the processing in Step S1 is as follows: Relative water depth , defined as: Relative water depth is the ratio of water depth h to wavelength L, expressed by the dimensionless parameter kh, where is the wave number, and the formula is as follows: ； Wave steepness Definition: Wave steepness is the ratio of wave height H to wavelength L and is usually expressed by the dimensionless parameter kH / 2. The formula is as follows: ； Relative immersion depth of oyster reef Definition: The relative immersion depth of an oyster reef is the ratio of the height of the oyster reef to the water depth The formula is as follows: ； Relative length of oyster reef Definition: The relative length of an oyster reef is the ratio of the length of the oyster reef to the wavelength and is usually expressed by the dimensionless parameter as shown in the following formula: ； Relative length of oyster reef spacing Definition: The relative distance between oyster reefs is the reef spacing divided by the wavelength and is expressed using the dimensionless parameter as follows: ； Gradient Definition: The riverbed gradient is the ratio of the change in riverbed height to the horizontal distance and is expressed using the dimensionless parameter as follows: ； Number of oyster reefs Definition: The number of oyster reefs is the total number of reef bodies arranged in the test area, usually represented by the dimensionless parameter N.

3. A method for quickly optimizing the wave dissipation performance of an underwater ecological submerged breakwater according to claim 1, characterized in that: In Step S3, the process of establishing the design matrix is specifically as follows: All combinations of the experiments are obtained according to the all-factor method as candidate points for the D-optimal design method, and then the design matrix is calculated using the fitted model of S2. , 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.

4. A method for quickly optimizing the wave dissipation performance of an underwater ecological submerged dike according to claim 3, characterized in that: In Step S3, the information matrix is calculated using the design matrix, specifically as follows: ； Among them, 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, and n represents the total number of experimental points; Calculate its determinant |M|. The design objective of D-optimal design is to maximize the determinant of the information matrix. Exchange the experimental points to change the design matrix, calculate the values of the determinants of different information matrices, and iterate until the design matrix corresponding to the maximum determinant is found to obtain the optimal combination of experimental points.

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