A prediction method, device and equipment for hydraulic parameters of dam overtopping breach

Abstract

The present invention discloses a method, device and equipment for predicting hydraulic parameters of dam overtopping and breaching. The method includes: performing grid division and establishing one-dimensional shallow water equations based on calculated grid points; obtaining each basic parameter of a flux vector and a source term vector; controlling the time step of the one-dimensional shallow water equations based on the CFL Courant number, and numerically discretely solving the one-dimensional shallow water equations by using a differential format of an explicit MacCormark prediction-correction scheme to obtain a conservation vector at the next moment, so as to realize the prediction of hydraulic parameters of water depth h and unit-width discharge q; introducing a TVD dissipation term near a shock wave, and discretely calculating the source term vector of the one-dimensional shallow water equations in each time step calculation. The present invention can predict the hydraulic parameters of dam overtopping and breaching, and overcomes the problems that the dam is too restricted by actual conditions such as weather and geographical location, and less prototype data is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of predicting hydraulic parameters of dam overtopping and breaching, and particularly relates to a method, device and equipment for predicting hydraulic parameters of dam overtopping and breaching. Background Art

[0002] In dam breaches, dam overtopping and breaching is the most common way of breaching. When actually studying the problem of dam overtopping and breaching, due to too many restrictions of the dam prototype by actual conditions such as weather and geographical location, less prototype data can be obtained. And for flume tests, whether large-scale or small-scale flume tests, they are restricted by models and actual conditions, and it is also difficult to completely obtain the hydraulic parameters of the overtopping and breaching prototype that conforms to the dam.

[0003] Therefore, there is an urgent need for an effective method to improve the prediction of hydraulic parameters in dam overtopping and breaching. Summary of the Invention

[0004] The purpose of the present invention is to provide a method, device and equipment for predicting hydraulic parameters of dam overtopping and breaching, so as to solve the technical problem that it is difficult to predict the hydraulic parameters of the overtopping and breaching prototype of the dam in the prior art.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, a method for predicting hydraulic parameters of dam overtopping and breaching is provided, including:

[0007] Based on the finite difference method, the river channel is meshed, and a one-dimensional shallow water equation is established according to the calculated grid points after meshing. Among them, the one-dimensional shallow water equation includes a conservation vector, a flux vector and a source term vector, and the variables of the conservation vector include water depth and unit-width discharge ;

[0008] Obtain the basic parameters of the flux vector and the source term vector, and input the basic parameters into the one-dimensional shallow water equation to solve the flux vector and the source term vector respectively;

[0009] Based on CFL the Courant number, control the time step of the one-dimensional shallow water equation, and use the difference format of the explicit MacCormark prediction-correction scheme to numerically discretize and solve the one-dimensional shallow water equation to obtain the conservation vector at the next moment, so as to realize the prediction of the hydraulic parameters water depth and unit-width discharge ;

[0010] Among them, when numerically discretizing and solving the one-dimensional shallow water equations using the differential format of the explicit MacCormark prediction-correction scheme, it is necessary to introduce a TVD dissipation term near the shock wave to calculate the conservation vector at the next moment, and the source term vector of the one-dimensional shallow water equations needs to be discretely calculated in each time step calculation.

[0011] In a possible design, the river channel is meshed based on the finite difference method, including:

[0012] Let the one-dimensional non-hydrostatic water flow velocity of the river channel be in the axis direction, and the axis is divided into several spatial grids , where the two ends of each spatial grid

[0013] are computational grid points.

[0014] ; (1)

[0015] Among them, , and represent the conservation vector, the flux vector, and the source term vector respectively, represents the time step, represents the spatial grid;

[0016] Among them, the conservation vector ; (2)

[0017] The flux vector ; (3)

[0018] The source term vector ; (4)

[0019] Among them, represents the channel width, that is, a function that varies along the channel direction, represents the acceleration due to gravity, represents the bottom slope source term, , represents the bottom bed elevation, represents the hydrostatic pressure term in the case of a rectangular cross-section, and respectively represent the influence of the change in the width of the rectangular river channel on the water depth and the discharge per unit width , represents the rate of change of the channel width in the channel length direction;

[0020] Among them, Denote the friction slope, which is calculated by the Manning formula as follows:

[0021] ; (5)

[0022] where, denotes the Manning roughness coefficient, denotes the hydraulic radius, and when the cross-section is rectangular .

[0023] In a possible design, before establishing the one-dimensional shallow water equations based on the divided computational grid points, the method further includes:

[0024] Setting the basic assumptions of the one-dimensional shallow water equations, including:

[0025] 1) The water flow participating in the operation is an incompressible fluid with a constant density;

[0026] 2) The water flow is a gradually varied flow, and the water pressure satisfies the hydrostatic pressure distribution law in the vertical direction;

[0027] 3) The wall friction resistance conforms to the Manning formula;

[0028] 4) The bottom slope is adapted to the calculation of the one-dimensional shallow water equations.

[0029] In a possible design, controlling the time step of the one-dimensional shallow water equations based on the CFL Courant number includes:

[0030] Based on CFL the Courant number, the time step of the one-dimensional shallow water equations is limited as follows:

[0031] ; (6)

[0032] ; (7)

[0033] where, denotes the depth-averaged cross-sectional velocity, denotes the propagation velocity of the free surface gravity wave in still water.

[0034] In a possible design, numerically discretizing and solving the one-dimensional shallow water equations using the explicit MacCormark predictor-corrector scheme's difference format to obtain the conservation vector at the next moment includes:

[0035] Numerically discretizing and solving the one-dimensional shallow water equations respectively based on the predictor step and the corrector step in the explicit MacCormark scheme as follows:

[0036] Predictor step: ; (8)

[0037] Corrector step: ; (9)

[0038] Among them, respectively represent the prediction step and the correction step, represents the unit node, and respectively represent the th time step and the th time step;

[0039] According to the calculation results of the prediction step and the correction step, the conservation vector at the next moment is obtained as follows:

[0040] (10);

[0041] Among them, in the prediction step, the spatial derivative adopts the forward difference format, and in the correction step, the spatial derivative adopts the backward difference format.

[0042] In a possible design, a TVD dissipation term is introduced near the shock wave as follows:

[0043]

[0044] Among them, and respectively represent the dissipation matrix of the TVD term, and respectively represent the divergence matrix of the TVD term;

[0045] According to the TVD dissipation term, the conservation vector at the next moment is calculated as follows:

[0046]

[0047]

[0048] ; (14)

[0049] Among them, represents the water depth of the th unit node at the th time step, represents the water depth of the th unit node in the prediction step, represents the water depth of the th unit node in the correction step, is the introduced parameter, represents the discharge per unit width of the th unit node at the th time step, represents the discharge per unit width of the th unit node in the prediction step, represents the The single-width discharge of a unit nodal correction step represents the eigenvalue.

[0050] In a possible design, during each time-step calculation, the source-term vector of the one-dimensional shallow-water equations needs to be discretely calculated, including:

[0051] In the discrete calculation of the topographic source term and the friction slope source term, a forward-difference format is used in the prediction step, and a backward-difference format is used in the correction step for discrete calculation, as follows:

[0052] Prediction-step source-term discrete format:

[0053]

[0054] Correction-step source-term discrete format:

[0055]

[0056] where represents the time index, represents the spatial index in the direction, is the spatial step length in the , and are respectively the mean values of the single-width discharge, water depth, and hydraulic radius at the node at time between node ;

[0057] In the discrete calculation caused by the change in river width, a forward-difference format is used in the prediction step, and a backward-difference format is used in the correction step for discrete calculation, as follows:

[0058] Prediction-step source-term discrete format:

[0059]

[0060]

[0061] Correction-step source-term discrete format:

[0062]

[0063]

[0064] In a second aspect, a prediction device for the hydraulic parameters of dam overtopping and breach is provided, including:

[0065] An equation establishment module, which is used to divide the river channel into grids based on the finite difference method and establish a one-dimensional shallow water equation according to the calculated grid points after division. Among them, the one-dimensional shallow water equation includes a conservation vector, a flux vector, and a source term vector, and the variables of the conservation vector include water depth and unit-width discharge ;

[0066] A parameter acquisition module, which is used to acquire the basic parameters of the flux vector and the source term vector, and input the basic parameters into the one-dimensional shallow water equation to solve the flux vector and the source term vector respectively;

[0067] A parameter prediction module, which is used to control the time step of the one-dimensional shallow water equation based on CFL the Courant number, and numerically discretize and solve the one-dimensional shallow water equation by using the differential format of the explicit MacCormark prediction-correction scheme to obtain the conservation vector at the next moment, so as to realize the prediction of the hydraulic parameters water depth and unit-width discharge ;

[0068] Among them, when numerically discretizing and solving the one-dimensional shallow water equation by using the differential format of the explicit MacCormark prediction-correction scheme, it is necessary to introduce a TVD dissipation term near the shock wave to calculate the conservation vector at the next moment, and it is necessary to discretely calculate the source term vector of the one-dimensional shallow water equation in each time step calculation.

[0069] In a third aspect, the present invention provides a computer device, which includes a memory, a processor, and a transceiver connected in sequence. Among them, the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the prediction method of the dam body overtopping and breaching hydraulic parameters described in any possible design of the first aspect.

[0070] In a fourth aspect, the present invention provides a computer-readable storage medium, which, when the instructions are run on a computer, executes the water flow evolution analysis method described in any possible design of the first aspect.

[0071] In a fifth aspect, the present invention provides a computer program product containing instructions, which, when the instructions are run on a computer, causes the computer to execute the water flow evolution analysis method described in any possible design of the first aspect.

[0072] The beneficial effects of the present invention compared with the prior art are:

[0073] The present invention establishes a mathematical model for dam overtopping and breach, controls the time step of the one-dimensional shallow water equation based on the CFL Courant number, and numerically discretely solves the one-dimensional shallow water equation using the explicit MacCormark predictor-corrector scheme's difference format to obtain the conservation vector at the next moment, thereby realizing the prediction of hydraulic parameters such as water depth and unit-width discharge ; wherein, when numerically discretely solving the one-dimensional shallow water equation using the explicit MacCormark predictor-corrector scheme's difference format, a TVD dissipation term needs to be introduced near the shock wave to calculate the conservation vector at the next moment, and the source term vector of the one-dimensional shallow water equation needs to be discretely calculated in each time step calculation, so as to be able to predict the hydraulic parameters of dam overtopping and breach, overcoming the problem that the dam is too restricted by actual conditions such as weather and geographical location and the prototype data obtained is less. Description of the Drawings

[0074] Figure 1 It is a flow chart of the method for predicting the hydraulic parameters of dam overtopping and breach in the embodiment of the present application;

[0075] Figure 2 is a schematic diagram of the flume test device in the embodiment of the present application;

[0076] Figure 3 is a schematic diagram of the overtopping and breach test groups and parameter settings in the embodiment of the present application;

[0077] Figure 4 is a schematic diagram of the initial state of the whole process of dam overtopping and breach in the embodiment of the present application;

[0078] Figure 5 is a schematic diagram of the water storage stage of the whole process of dam overtopping and breach in the embodiment of the present application;

[0079] Figure 6 is a schematic diagram of the water flow overtopping stage of the whole process of dam overtopping and breach in the embodiment of the present application;

[0080] Figure 7 It is a schematic diagram of the dam erosion stage of the whole process of dam overtopping and breach in the embodiment of the present application;

[0081] Figure 8 It is a schematic diagram of the stable stage of the whole process of dam overtopping and breach in the embodiment of the present application;

[0082] Figure 9 It is a schematic diagram of the water level comparison diagram of Group 1 of Case 1 in the embodiment of the present application;

[0083] Figure 10 It is a schematic diagram of the water level comparison of Group 2 of Case 2 in the embodiment of the present application;

[0084] Figure 11 It is a schematic diagram of the water level comparison of Group 3 of Case 3 in the embodiment of the present application;

[0085] Figure 12For Case 4 of the embodiments of the present application: Schematic diagram of water level comparison;

[0086] Figure 13 Schematic diagram of the initial moment of the water flow evolution process of the embodiments of the present application;

[0087] Figure 14 Schematic diagram of the critical moment of the water flow evolution process of the embodiments of the present application;

[0088] Figure 15 Schematic diagram of the general moment of the water flow evolution process of the embodiments of the present application;

[0089] Figure 16 Schematic diagram of the water level - storage capacity curve of Tangjiashan of the embodiments of the present application;

[0090] Figure 17 Schematic diagram of the comparison of the calculation results of the dam break of Tangjiashan of the embodiments of the present application. Specific embodiments

[0091] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the present invention in combination with the accompanying drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the accompanying drawings is only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation to the present invention.

[0092] Embodiment

[0093] In order to solve the technical problem that it is difficult to predict the hydraulic parameters of the prototype of the overtopping dam break in the prior art. The embodiments of the present application propose a method for predicting the hydraulic parameters of the overtopping dam break. This method establishes a mathematical model of the overtopping dam break, controls the time step of the one - dimensional shallow water equation based on CFL the Courant number, numerically discretizes and solves the one - dimensional shallow water equation using the difference format of the explicit MacCormark prediction - correction scheme to obtain the conservation vector at the next moment, thereby realizing the prediction of the hydraulic parameters of water depth and unit discharge ; wherein, when numerically discretizing and solving the one - dimensional shallow water equation using the difference format of the explicit MacCormark prediction - correction scheme, a TVD dissipation term needs to be introduced near the shock wave to calculate the conservation vector at the next moment, and the source term vector of the one - dimensional shallow water equation needs to be discretely calculated in each time step calculation, so as to be able to predict the hydraulic parameters of the overtopping dam break, overcoming the problems that the dam is too restricted by actual conditions such as weather and geographical location, and the obtained prototype data is less.

[0094] The prediction method for hydraulic parameters of dam overtopping breach provided in the embodiments of the present application will be described in detail below.

[0095] It should be noted that the prediction method for hydraulic parameters of dam overtopping breach provided in the embodiments of the present application can be applied to any terminal device. Among them, the operating system includes but is not limited to Windows system, Mac system, Linux system, Chrome OS system, UNIX operating system, IOS system, Android system, etc., which are not limited here; among them, the terminal device includes but is not limited to servers, IPAD tablets, personal mobile computers, industrial computers, personal computers, etc., which are not limited here. For the convenience of description, unless otherwise specified, the embodiments of the present application are described with a server as the execution entity. It can be understood that the execution entity does not constitute a limitation on the embodiments of the present application. In some other embodiments, other types of terminal devices can be used as the execution entity.

[0096] As Figure 1 shown, it is a flowchart of the prediction method for hydraulic parameters of dam overtopping breach provided in the embodiments of the present application. The water flow evolution analysis method includes but is not limited to being implemented by steps S1 to S3:

[0097] Step S1. Divide the river channel into grids based on the finite difference method, and establish a one-dimensional shallow water equation according to the calculated grid points after division. Among them, the one-dimensional shallow water equation includes a conservation vector, a flux vector, and a source term vector. The variables of the conservation vector include water depth and unit-width discharge ;

[0098] It should be noted that the finite difference method (Finite Difference Methods, abbreviated as FDM) is the most primitive method for simulating shallow water flow. So far, it is still widely used and is also the basis of other numerical methods. This method is based on the Taylor series expansion, and by approximating the derivative terms in the differential equation in the form of differences, the equation is discretized. The difference forms mainly include forward difference, backward difference, and central difference, etc. The differential format of the explicit MacCormark prediction-correction scheme (MacCormack Predictor–Corrector Scheme) is used for numerical discrete solution. This explicit difference format can solve both gradually changing and rapidly changing flows. Because the MacCormark scheme is second-order accurate in time and space, this method brings good resolution, and the numerical method is relatively simple and does not require large-scale matrix operations. It has been widely used in the simulation of fluid evolution analysis.

[0099] In a possible design, grid division of the river channel is performed based on the finite difference method, including:

[0100] Let the one-dimensional non-hydrostatic water flow velocity of the river channel be in the axis direction, and the axis is divided into several spatial grids using the finite difference method, where the two ends of each spatial grid

[0101] are computational grid points. x It should be noted that in the embodiments of the present application, spatial grids with a constant grid spacing are used in the h direction. The differential grid of the plane is shown in Figure 1. The variables in the conservation vector in the shallow water equation q and i are located at the grid points in the middle position between adjacent grids. The position length of the th grid point is i-1 / 2 . The control range of the grid point is the control volume up to Δx. The variables in the flux vector are located at the midpoint between the i th grid point and the i+1 th grid point, that is, on both sides of the control volume. At the same time, due to the existence of boundary conditions, there is a boundary node on each side of the computational domain (from the 1st grid point to the j th grid point), namely and , which are used to store the boundary conservation vector.

[0102] In a possible design, before establishing the one-dimensional shallow water equation according to the divided computational grid points, the method further includes:

[0103] Setting the basic assumption conditions of the one-dimensional shallow water equation, including:

[0104] 1) The water flow participating in the operation is an incompressible fluid with a constant density;

[0105] 2) The water flow is a gradually varied flow, or in other words, the wavelength is much larger than the water depth, and the water pressure satisfies the hydrostatic pressure distribution law in the vertical direction;

[0106] 3) The wall friction resistance conforms to the Manning formula;

[0107] 4) The bottom slope is adapted to the calculation of the one-dimensional shallow water equation, that is, the bottom slope is moderate.

[0108] It should be noted that the basis for making these assumptions is to make the operation more convenient. For example, if it is not assumed to be an incompressible fluid, then the change in fluid density caused by compression must be considered in the calculation, which will increase the complexity of the solution.

[0109] In a possible design, a one-dimensional shallow water equation is established based on the divided computational grid points as follows:

[0110] ; (1)

[0111] Wherein, 、 and represent the conservation vector, the flux vector, and the source term vector respectively, represents the time step, represents the spatial grid;

[0112] Wherein, the conservation vector ; (2)

[0113] The flux vector ; (3)

[0114] The source term vector ; (4)

[0115] Wherein, represents the channel width, which is a function varying along the channel direction, represents the acceleration due to gravity, represents the bed slope source term, , represents the bed elevation, represents the hydrostatic pressure term in the case of a rectangular cross-section, and respectively represent the effects of the change in the width of the rectangular channel on the water depth and the discharge per unit width , represents the rate of change of the channel width in the channel length direction;

[0116] Wherein, represents the friction slope, which is calculated by the Manning formula as follows:

[0117] ; (5)

[0118] Wherein, represents the Manning roughness coefficient, represents the hydraulic radius, and when the cross-section is rectangular .

[0119] It should be noted that the effects brought by the lateral inflow, the wind resistance term, and the Coriolis force in the control equation can be ignored. Therefore, these additional terms are not included in the equation. Ignoring these effects brings great convenience to the numerical simulation and is also reasonable.

[0120] Step S2. Obtain the basic parameters of the flux vector and the source term vector, and input the basic parameters into the one-dimensional shallow water equations to solve the flux vector and the source term vector respectively;

[0121] Preferably, the basic parameters of the flux vector and the source term vector can be obtained through on-site investigations, literature materials, remote sensing, hydrology, etc. Among them, the basic parameters include, but are not limited to, the channel width B, the bed elevation z, the bottom slope source term , the Manning roughness coefficient M, the hydraulic radius R, the depth-averaged cross-sectional velocity u at each computational grid point, and the propagation velocity c of the free surface gravity wave in still water at each computational grid point, so as to obtain the necessary parameters for subsequent calculations.

[0122] Step S3. Control the time step of the one-dimensional shallow water equations based on the CFL Courant number, and use the differential format of the explicit MacCormark prediction-correction scheme to numerically discretize and solve the one-dimensional shallow water equations to obtain the conservation vector at the next moment, thereby realizing the prediction of the hydraulic parameters water depth and the unit-width discharge ;

[0123] Among them, when using the differential format of the explicit MacCormark prediction-correction scheme to numerically discretize and solve the one-dimensional shallow water equations, a TVD dissipation term needs to be introduced near the shock wave to calculate the conservation vector at the next moment, and the source term vector of the one-dimensional shallow water equations needs to be discretely calculated in each time step calculation.

[0124] In a possible design, controlling the time step of the one-dimensional shallow water equations based on CFL the Courant number includes:

[0125] Based on CFL the Courant number, the time step of the one-dimensional shallow water equations is limited as follows:

[0126] ; (6)

[0127] ; (7)

[0128] Among them, represents the depth-averaged cross-sectional velocity, represents the propagation velocity of the free surface gravity wave in still water.

[0129] Among them, it should be noted that by setting the time step to a fixed value, then the time step should be the minimum value at this moment or during the whole process, so as to make the calculation process stable; CFLThe value range is [0, 1]. To improve the computational efficiency and stability of the model, it should be noted that the embodiments of this application adopt the time-varying time step technology. Before the start of each time step simulation, the most appropriate time step Δt in this process needs to be calculated.

[0130] In a possible design, the one-dimensional shallow water equations are numerically discretized and solved using the difference format of the explicit MacCormark prediction-correction scheme to obtain the conservation vector at the next moment, including:

[0131] The one-dimensional shallow water equations are numerically discretized and solved respectively based on the prediction step and the correction step in the explicit MacCormark scheme as follows:

[0132] Prediction step: ; (8)

[0133] Correction step:

[0134] Among them, respectively represent the prediction step and the correction step, represents the unit node, and respectively represent the th time step and Article th time step;

[0135] According to the calculation results of the prediction step and the correction step, the conservation vector at the next moment is obtained as follows:

[0136] (10);

[0137] Among them, the spatial derivative in the prediction step adopts the forward difference format, and the spatial derivative in the correction step adopts the backward difference format.

[0138] In a possible design, a TVD dissipation term is introduced near the shock wave as follows:

[0139]

[0140] Among them, and respectively represent the dissipation matrix of the TVD term, and respectively represent the divergence term matrix of the TVD term;

[0141] Among them, the TVD dissipation matrix and R i-1 / 2 are defined as follows:

[0142] ;

[0143] ;

[0144] wherein It represents the eigenvalue and is calculated as follows:

[0145] ;

[0146] ;

[0147] ;

[0148] ;

[0149] in, represents the depth-averaged cross-sectional velocity, represents the propagation speed of free surface gravity waves in still water;

[0150] Among them, the TVD dissipation matrix and Φ i-1 / 2 The definition is as follows:

[0151] ;

[0152] ;

[0153] in, The term is the calculation process and The principle is the same, so the following only applies to The derivation and calculation process of the term is explained as follows:

[0154] ;

[0155] Among them, the function in the equation Yes The entropy correction of It means that the artificial numerical error introduced by using TVD correction is eliminated or reduced by incorporating it into the TVD dissipation term;

[0156] ;

[0157] ;

[0158] in, The value of is a very small positive value determined according to different problems, and the calculation formula is as follows:

[0159] ;

[0160] The limiter function For the flux limiter, the limiter function selected in the embodiments of the present application can obtain a non-oscillatory solution in strong gradients or shocks, and the expression is as follows:

[0161] ;

[0162] Among them, is the characteristic ratio of the limiter parameter:

[0163]

[0164] Among them, By incorporating it into the TVD dissipation term, the artificial numerical error introduced by using the TVD correction is eliminated or reduced:

[0165] ;

[0166] Among them, represents a function of the water surface elevation, H = h + zd For the water depth h , it is more suitable to represent ;

[0167] Calculate the conservation vector at the next moment according to the TVD dissipation term, as follows:

[0168]

[0169]

[0170] ; (14)

[0171] Among them, represents the water depth of the th unit node at the th time step, represents the water depth of the th unit node at the prediction step, represents the water depth of the th unit node at the correction step, is the introduced parameter, represents the th unit node at the th time step of the unit-width flow rate, represents the th unit node at the prediction step of the unit-width flow rate, represents the th unit node at the correction step of the unit-width flow rate, represents the eigenvalue.

[0172] Since traditional linear formats usually have difficulty in simultaneously meeting the requirements of high-order accuracy and suppressing spurious oscillations, it is necessary to perform discrete processing on the source terms of the equations. In one possible design, during each time-step calculation, discrete calculations need to be performed on the source-term vector of the one-dimensional shallow-water equations, including:

[0173] In the discrete calculations of the topographic source term and the friction slope source term, a forward-difference format is used in the prediction step, and a backward-difference format is used in the correction step for discrete calculations, as follows:

[0174] Discrete format of the source term in the prediction step:

[0175]

[0176] Discrete format of the source term in the correction step:

[0177]

[0178] Wherein, represents the time index, represents the spatial index in the direction, is the spatial step size in the direction, and are respectively the mean values of the discharge per unit width, water depth, and hydraulic radius at the node at time between node and node

[0179] In the discrete calculations caused by the change in river width, a forward-difference format is used in the prediction step, and a backward-difference format is used in the correction step for discrete calculations, as follows:

[0180] Discrete format of the source term in the prediction step:

[0181]

[0182]

[0183] Discrete format of the source term in the correction step:

[0184]

[0185]

[0186] Based on the above-disclosed content, the embodiments of the present application establish a mathematical model for dam overtopping and breach, control the time step of the one-dimensional shallow-water equations based on the CFL Courant number, and numerically discretize and solve the one-dimensional shallow-water equations using the explicit MacCormark prediction-correction scheme's difference format to obtain the conservation vector at the next moment, thereby realizing the water depth of the hydraulic parameters and unit-width discharge Prediction; when numerically discretizing and solving the one-dimensional shallow water equations using a differential format of the explicit MacCormark prediction-correction scheme, a TVD dissipation term needs to be introduced near the shock wave to calculate the conservation vector at the next moment, and the source term vector of the one-dimensional shallow water equations needs to be discretely calculated in each time step calculation, so as to be able to predict the hydraulic parameters of dam overtopping and breach, overcoming the problem that the dam is too restricted by actual conditions such as weather and geographical location, and obtaining less prototype data.

[0187] A second aspect provides a device for predicting the hydraulic parameters of dam overtopping and breach, including:

[0188] An equation establishment module, configured to divide the river channel into grids based on the finite difference method, and establish the one-dimensional shallow water equations according to the calculated grid points after division, where the one-dimensional shallow water equations include a conservation vector, a flux vector, and a source term vector, and the variables of the conservation vector include water depth and unit-width discharge ;

[0189] A parameter acquisition module, configured to acquire the basic parameters of the flux vector and the source term vector, and input the basic parameters into the one-dimensional shallow water equations to solve the flux vector and the source term vector respectively;

[0190] A parameter prediction module, configured to control the time step of the one-dimensional shallow water equations based on CFL the Courant number, and numerically discretize and solve the one-dimensional shallow water equations using a differential format of the explicit MacCormark prediction-correction scheme to obtain the conservation vector at the next moment, so as to realize the prediction of the hydraulic parameters of water depth and unit-width discharge ;

[0191] Wherein, when numerically discretizing and solving the one-dimensional shallow water equations using a differential format of the explicit MacCormark prediction-correction scheme, a TVD dissipation term needs to be introduced near the shock wave to calculate the conservation vector at the next moment, and the source term vector of the one-dimensional shallow water equations needs to be discretely calculated in each time step calculation.

[0192] For the working process, working details and technical effects of the foregoing device provided in the second aspect of this embodiment, reference may be made to the method described in the first aspect or any possible design in the first aspect above, and details are not described herein again.

[0193] In a third aspect, the present invention provides a computer device, including a memory, a processor, and a transceiver that are communicatively connected in sequence. Among them, the memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer programs and execute the method described in any possible design of the first aspect.

[0194] Specifically, the memory may include, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a flash memory, a first in first out memory (FIFO), and / or a first in last out memory (FILO), etc.; the processor may not be limited to using a microprocessor of the STM32F105 series; the transceiver may include, but is not limited to, a WiFi (Wireless Fidelity) wireless transceiver, a Bluetooth wireless transceiver, a GPRS (General Packet Radio Service) wireless transceiver, and / or a ZigBee (a low-power local area network protocol based on the IEEE802.15.4 standard) wireless transceiver, etc. In addition, the computer device may further include, but is not limited to, a power module, a display screen, and other necessary components.

[0195] For the working process, working details, and technical effects of the foregoing computer device provided in the third aspect of this embodiment, reference may be made to the method described in the first aspect or any possible design in the first aspect above, and details are not repeated here.

[0196] In a fourth aspect, the present invention provides a computer-readable storage medium, on which instructions are stored. When the instructions are run on a computer, the method described in any possible design of the first aspect is executed.

[0197] Among them, the computer-readable storage medium refers to a carrier for storing data, which may include, but is not limited to, a floppy disk, an optical disc, a hard disk, a flash memory, a USB flash drive, and / or a memory stick, etc. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0198] For the working process, working details, and technical effects of the foregoing computer-readable storage medium provided in the fourth aspect of this embodiment, reference may be made to the method described in the first aspect or any possible design in the first aspect above, and details are not repeated here.

[0199] Fifth aspect, the present invention provides a computer program product comprising instructions that, when run on a computer, cause the computer to execute the method described in any possible design of the first aspect.

[0200] For the working process, working details and technical effects of the aforementioned computer program product comprising instructions provided in the fifth aspect of this embodiment, reference may be made to the method described in the first aspect or any possible design in the first aspect above, and details will not be elaborated herein.

[0201] Application Example 1

[0202] By applying the above embodiments to the dam overtopping breach flume test, the method of the embodiments of the present application is verified as follows:

[0203] Based on the existing flume tests, four groups of tests under different conditions are selected for numerical verification. The verification mainly includes two aspects: different incoming flows and different dam slopes. The flume tests are mainly for a single dam without an initial breach, and the incoming flow rates are 0.012 m 3 / s, 0.025 m 3 / s, 0.042 m 3 / s, and the dam slopes and S f are 2 and 3, 4 and 5 respectively.

[0204] The large-scale tests carried out are completed in an indoor flume. The test flume is 80 m long, 1.2 m wide and 0.8 m high horizontally. In the test, a water pump is used to lead the clear water in the reservoir into the flume through a water delivery pipeline, and an electromagnetic flowmeter is installed to record and calibrate the incoming flow rate. At the same time, twelve automatic water level gauges are placed in the test to record the water surface elevations at different cross-sections. In this chapter, only the data of three automatic water level instruments are taken for verification, which are located at 19 m (WZ1), 29 m (WZ2) and 40 m (WZ3) from the water inlet of the flume. Since a certain water depth is required when using the automatic water level gauge, there are initial water depths upstream and downstream of the flume test. In order to store water level downstream, a water retaining weir with a height of 0.15 m is placed near the end of the flume. The schematic diagram of the flume is shown in Figure 2.

[0205] The test dam materials are all selected as purely non-cohesive sand (SA for short), which is directly obtained by using a sieve smaller than 2.0 mm, and the median particle size of this material is 0.8 mm. In the test, the dam height is all 40 cm, where is the incoming flow rate, is the slope ratio of the upstream slope, is the slope ratio of the downstream slope, is the initial water depth upstream, is the initial downstream water depth. A total of four groups, namely Case 1 - Case 4, are selected, and the corresponding test groups for Yue Zhiyuan are: F - Case8, F - Case9, F - Case11, F - Case15. The test conditions are shown in Figure 3 .

[0206] The numerical model calculation domain is selected as [0m, 78m]. Since the position of the water retaining weir is two meters away from the outlet, the calculation domain is two meters shorter than the actual flume length. A total of 781 grids are divided, and the other parameters of the model are respectively: = 9.81m / s 2 , = 0.8mm, = 1×103kg / m 3 , = 2.65×103kg / m 3 , = 0.4, = 0.12, CFL = 0.8. The upstream boundary is set as a unit - width incoming flow boundary. Due to the existence of the water retaining weir downstream, only the downstream water depth boundary needs to be restricted to 0.15m (the height of the water retaining weir) and the minimum value of the adjacent boundary water depth.

[0207] The whole process of dam - overtopping breach includes four stages: water storage in front of the dam, water flowing over the dam, scouring of the dam surface, and finally the breach flow maintaining a stable state. The numerical simulation of the whole process of dam - overtopping breach should be consistent with these four stages so as to more realistically simulate the water flow evolution and dam body erosion during the whole process of dam - overtopping breach.

[0208] Taking the following experimental settings as an example, to explore the simulation of the whole process of dam - overtopping breach under the conditions of this experimental group, where the horizontal and vertical ratios in the figures are 0.12 when not otherwise specified.

[0209] The first stage: In the water - storage stage in front of the dam, the water storage from the initial storage capacity to the water level in front of the dam being the same as the dam - top elevation. Figure 4 is the water level and dam - body elevation in the initial state. The upstream water level is 5.4cm, and the downstream water level is 4.8cm. The water level in front of the dam gradually rises with the incoming flow until the water level reaches the dam - top elevation, and then the second stage begins. Figure 5 is the water level and dam - body elevation during the water - storage process. It can be seen that the water flow has good climbing ability during the water - storage process and there are no large - amplitude fluctuations.

[0210] The second stage: In the stage of water flowing over the dam, the water flows through the breach (or the dam top) to the back - water slope, and then gradually starts to erode the dam body. Figure 6 is the water level and dam - body elevation when the water flow reaches the dam top. The water flow will gradually flow over the dam top. At the same time, the breach - flow rate at the dam top is small in this stage, so the water level in front of the dam will also gradually rise. This is consistent with the numerical simulation results.

[0211] The third stage: After the water flow in the dam body erosion stage reaches the back slope, the water level in front of the dam will gradually rise, causing the evolution of the water flow on the back slope to gradually accelerate, and the flow of the burst water will gradually increase. At the same time, the dam body begins to erode. The dam body erosion will start from the back slope and the dam top, and gradually burst to the front slope of the dam body. Figure 7 The water level and dam elevation in the erosion stage (Note: The flume test diagram is a test phenomenon diagram, not the actual phenomenon of the case, and is only for illustration). It can be seen that the water flow on the dam top will drop first due to the erosion of the dam top, and the water level distribution in front of the dam is "high in front and low in the back", that is, the water level near the front of the flume is higher than the water level at the dam top. At the same time, a water jump phenomenon occurs at the dam foot on the back slope, which is consistent with the actual test.

[0212] The fourth stage: After the outburst flow rate rises first and then decreases in a bell shape during the outburst stage, it will gradually stabilize, and the shape of the dam body will gradually stabilize, and finally reach a stable state, with the dam body elevation remaining basically unchanged. After the outflow rate stabilizes in this stage, it will be consistent with the flow rate of the entire section. Figure 8 (The figure shows a 0.01 aspect ratio) for the water level and dam elevation in the stable stage. It can be seen that the water levels at the front and rear ends of the flume are basically the same. The water level at the rear end of the flume is not less than 0.15m due to the presence of the water retaining weir. However, due to the presence of the dam, the water level numerical result shows a slight mutation at the dam foot on the back slope. This is because the terrain source term is not completely conserved at the terrain mutation point, but it does not affect the process of water flow evolution.

[0213] By comparing the water level results during the entire numerical simulation process with the flume test process, as well as analyzing some phenomena during the test process, it can be found that the water storage in front of the dam, water overtopping, and dam erosion experienced during the water flow evolution process in the numerical calculation are basically consistent with the test process. At the same time, after the water overtopping, a hydraulic jump phenomenon occurs at the foot of the dam on the back slope. This phenomenon occurs in both numerical simulation and flume tests, which further verifies the applicability of the numerical results.

[0214] Based on the above, the numerical results of the selected test cases were verified, including the comparison of the results of different inflows and different dam slopes in the test. Each test includes the entire process from water storage to breach stability of the dam. Because each group of test conditions is different, they are compared separately. The comparison results are mainly the water level change process lines at three section positions, which are WZ1, WZ2 and WZ3 respectively. The measured value results come from the existing research results.

[0215] Figure 9 , 10 and Figure 11For the comparison of the calculated water level process line and the measured process water level line in the case of dam breach without breach under different incoming flows. Obviously, during the water storage stage, the dam overtopping stage, and the early stage of dam erosion of the water level, the water level shows a gradually increasing trend until the water level peak. At the same cross-section position, taking the WZ1 position as an example, Figure 9 In case 1 in (a), it reaches the peak at about 1400 s, Figure 10 In case 2 in (a), it reaches the peak at about 650 s, and Figure 11 In case 3 in (a), it reaches the peak at about 400 s, which is in good agreement with the actual test results and laws. When factors such as the dam elevation are the same, the time for the cross-section water level to reach the peak water level will decrease as the incoming flow rate increases. In the same test group, taking case 1 group as an example, Figure 9 WZ1 in (a), Figure 9 WZ2 in (b), Figure 9 WZ3 in (c) all reach the peak at about 1400 s. This is obvious. The water level in front of the dam is similar to a whole, resulting in the result of "rising and falling together". At the same time, after stabilization, the water levels of each cross-section are almost the same, which is also easy to understand. It can be seen from the above three groups of figures that in the case of the same dam, whether it is a large flow or a small flow, the numerical model of the embodiment of the present application can more accurately describe the overtopping water flow evolution process.

[0216] Figure 10 and Figure 12 Comparison of the calculated water level process line and the measured process water level line of the test group under the condition that other conditions are the same except for the different dam slopes. Under the same flow rate and the same dam crest elevation, the time required for the water storage in front of the dam to start from overtopping and breaching is basically the same, only differing by about 8 s. The main difference is that after overtopping and breaching, the case 2 group with a larger dam slope reaches a stable state earlier than the case 4 group with a smaller dam slope. At the same time, at the same elapsed time, when the slope is larger, the water level at the same position is smaller. Taking 1000 s as an example, the water level of WZ1 in case 2 is 0.16 m, which is smaller than the water level of WZ1 in Case 4, which is 0.18 m. This is because in a steeper dam type, the flow velocity of the water flow in the steep slope is greater than that in the gentle slope, so it will cause greater erosion to the dam body, and finally reach a stable state earlier in the steeper dam slope, and the water level at the same elapsed time is also smaller. It can be clearly seen from the numerical results that the model has relatively accurate numerical results whether in a gentler slope (case 5) or a steeper slope (case 2).

[0217] It should be noted that the measured water level value in the indoor flume test shows that the water level in the test is "wavy", but only in the rising section of the water level. During the water storage stage of the reservoir capacity in front of the dam, even if an energy dissipation net is placed in front of the dam, a certain degree of water surface fluctuation will occur.

[0218] By observing the flume test process, it can be found that this phenomenon is mostly caused by the gradual increase of water flow near the water-facing slope of the dam body when water is stored in front of the dam. At the same time, the water flow near the dam body constantly "impacts" the water-facing slope of the dam body and then "rebounds", causing water level fluctuations. At the same time, the numerical simulation results of the dam body breach can intuitively show the cause of the "wave-like" water level change. Figure 13 As shown, (a) is t Water level diagram at each position at time 1, (b) Figure is t 1 and t 2. Flow diagram of each location at time, where t 2> t 1. The water level of each section in front of the dam will gradually increase with the evolution of the water flow. The water level at the location where the water flows is "high on the left and low on the right". The single-width flow characteristics are the same as the water level, and the single-width flow at each location at time t2 is greater than t The flow rate of single width at each position at time 1. Until the water flow contacts the upstream slope of the dam body, the flow rate of single width at the contact point is zero. Figure 15 . Then the water flow climbs up, and after the water flow climbs up, there will be a reflected water flow in the opposite direction of the original direction. The reflected water flow propagating to the left will reduce the single-width flow rate at the location it passes. Figure 15 (b) t At 1 second, the black line changes to t At 2 o'clock, the blue line is shown. At the same time, the inflow propagating to the right increases the single-width flow rate of the location it passes through. Until the reflected water flow and the inflow water flow come into contact, the effect of the inflow water flow is obviously greater than that of the reflected water flow, and the water level at each location gradually rises. Figures 9 to 12 It can be seen that the amplitude of the “wave-like” water level in sections WZ1, WZ2, and WZ3 gradually increases, and the “wave-like” is the largest at WZ3. This phenomenon is consistent with the numerical simulation results and the flume test results.

[0219] It can be seen from the numerical simulation results of the above four groups of indoor water tank tests that they all maintain good consistency. At the same time, the "wave-like" rise of water level during the water storage stage is also the same, which fully verifies the numerical stability and accuracy of the numerical model established in this paper in solving the burst water flow in the whole process of burst. This phenomenon also further supplements the study of indoor water tank tests on dam burst.

[0220] Application Example 2: Numerical Model Analysis of Tangjiashan Dam Breach

[0221] The terrain of Tangjiashan Dam varies greatly, and the geological conditions are complex. The longitudinal section for calculation is selected as the center line of the discharge channel. The calculation domain is selected from the dam crest to the toe of the back slope, that is, in the range of [200m, 800m]. The shape of the dam body in the longitudinal section within this calculation domain is given according to the measured data. The slope drop average value is set for the downstream slope to ensure calculation stability and convergence. The roughness coefficient within the calculation domain is set according to the "Hydraulic Calculation Manual" and is rechecked using relevant experience, and the roughness coefficient is selected as 0.045. The initial water level is set at 742.18m, and the initial flow rate is set at 131.6m 3 / s. In the initial stage of dam overtopping and breach, the channel shape is approximately a trapezoidal breach. The initial bottom width of the channel is 8m, the initial depth is 13m, the slope ratio of the side slope is 1:1.5, the median grain size is taken as 0.01m, the gravitational acceleration is 9.81m, and the CFL coefficient is taken as 0.8.

[0222] The calculation domain is selected starting from the dam crest and does not include the information of the reservoir capacity in front of the dam. In order to more accurately reflect the actual situation of Tangjiashan Dam, the upstream boundary is set as the measured water level - reservoir capacity curve of Tangjiashan, and the downstream boundary is a free outflow boundary. The downstream free outflow boundary has been described and will not be elaborated here. Now, the setting of the upstream boundary will be mainly elaborated.

[0223] For the convenience of explanation, the water depth at the upstream boundary is set as , the discharge per unit width at the upstream boundary is set as , the water depth within the calculation domain is set , the discharge per unit width within the calculation domain is set as , the dam elevation is set as , where is the calculation grid point, is the time step. The calculation steps are as follows:

[0224] At the initial moment, the water depth at the upstream boundary is determined by the initial water depth , which is also the water level elevation here. Similarly, the discharge per unit width at the upstream boundary is set , that is, the flow velocity is the same. At the same time, the initial reservoir capacity is determined by linear interpolation through the water level - reservoir capacity curve and . The measured water level - reservoir capacity curve of Tangjiashan can be seen in Figure 16 .

[0225] According to the initial conditions and the upstream and downstream boundaries, the hydraulic parameters at the next moment are calculated through the shallow water equations 、 . At this time, is used as the discharge per unit width of the outflow and the reservoir capacity at the next moment is calculated through the water balance equation . The water balance equation is shown in Equation (1).

[0226] (1)

[0227] In the formula: is the reservoir storage capacity; is the inflow rate, which is taken as 118.0 m 3 / s in this example; is the breach discharge, , is the average width in the depth direction at the corresponding position. Therefore, the reservoir storage capacity at the next moment is . Then, the new water depth is calculated by interpolation through the water level-storage capacity curve as the boundary condition . Subsequently, according to the initial conditions and the upstream and downstream boundaries, the hydraulic parameters at the next moment are calculated by the shallow water equations.

[0228] The complete loop calculation in step ② is used until the running time number is greater than the set time, and the entire numerical calculation ends.

[0229] The numerical calculation time of Tangjiashan is set to 54000 s in total, corresponding to the time period from 3:00 h to 18:00 h in the actual case of Tangjiashan Dam. The measured results of the breach discharge and the water level in the reservoir are selected for comparison. Figure 17 is the comparison result between the numerical results and the measured values of Tangjiashan Dam. Figure 17 (a) is the comparison of the water level process line in the reservoir. The change trend of the calculated water level value is the same as that of the measured value. The change of the water level is not obvious at the beginning stage. The water level starts to drop rapidly at about 9 h, and then starts to drop slowly after 12 h. A certain deviation appears in the calculated value after about 14 h. The dropping speed of the calculated water level value in the reservoir becomes slower, and the calculated value gradually becomes higher than the predicted value. Figure 17 (b) is the comparison result of the breach discharge process line. The change trend of the calculated value of the breach discharge process line is basically the same as that of the measured value. The arrival time of the peak value of the breach discharge is basically the same. The calculated peak value of the breach discharge is 6283 m 3 / s, which is smaller than the measured value.

[0230] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A prediction method for hydraulic parameters of dam overtopping breach, characterized in that, including: The river channel is meshed based on the finite difference method, and a one-dimensional shallow water equation is established according to the calculated grid points after meshing. Among them, the one-dimensional shallow water equation includes a conservation vector, a flux vector, and a source term vector. The variables of the conservation vector include water depth and discharge per unit width ; Obtain the basic parameters of the flux vector and the source term vector, and input the basic parameters into the one-dimensional shallow water equation to solve the flux vector and the source term vector respectively; Based on CFL the Courant number controls the time step of the one-dimensional shallow water equations, and a differential format of the explicit MacCormark predictor-corrector scheme is used to numerically discretize and solve the one-dimensional shallow water equations to obtain the conservation vector at the next moment, thereby realizing the prediction of the hydraulic parameters water depth and unit-width discharge ; Wherein, when numerically discretely solving the one-dimensional shallow water equation by using the explicit MacCormark predictor-corrector scheme difference format, it is necessary to introduce a TVD dissipation term near the shock wave to calculate the conservation vector at the next moment, and it is necessary to discretely calculate the source term vector of the one-dimensional shallow water equation in each time step calculation; Wherein, numerically discretely solving the one-dimensional shallow water equation by using the explicit MacCormark predictor-corrector scheme difference format to obtain the conservation vector at the next moment, including: Numerically discretely solve the one-dimensional shallow water equation respectively based on the predictor step and the corrector step in the explicit MacCormark scheme as follows: Prediction step: ; (8) Calibration step: ; (9) Among them, respectively represent the prediction step and the correction step, represents the unit node, and respectively represent the th time step and the th time step; Obtain the conservation vector at the next moment according to the calculation results of the predictor step and the corrector step as follows: （10）； Wherein, the forward difference format is adopted for the spatial derivative in the predictor step, and the backward difference format is adopted for the spatial derivative in the corrector step; Wherein, introduce the TVD dissipation term near the shock wave as follows: Among them, and respectively represent the dissipation matrix of the TVD term, and respectively represent the diffusion term matrix of the TVD term; Calculate the conservation vector at the next moment according to the TVD dissipation term as follows: ；（14） Among them, represents the water depth of the th unit node at the th time step, represents the water depth of the th unit node at the prediction step, represents the water depth of the th unit node at the correction step, is an introduced parameter, represents the discharge per unit width of the th unit node at the th time step, represents the discharge per unit width of the th unit node at the prediction step, represents the discharge per unit width of the th unit node at the correction step, represents the eigenvalue.

2. The prediction method for hydraulic parameters of dam overtopping breach according to claim 1, characterized in that, Mesh the river channel based on the finite difference method, including: Let the one-dimensional non-hydrostatic water flow velocity of the river channel be in the axial direction, and use the finite difference method to divide the axis into several spatial grids , where each spatial grid has calculation grid points at both ends.

3. The prediction method for hydraulic parameters of dam overtopping breach according to claim 2, characterized in that, Establish the one-dimensional shallow water equation according to the calculated grid points after division as follows: ；（1） Among them, , and represent the conserved vector, the flux vector, and the source term vector respectively, represents the time step, represents the spatial grid; Among them, the conserved vector ; (2) Flux vector ; (3) Source item vector ; (4) Among them, represents the channel width, which is a function varying along the channel direction, represents the acceleration due to gravity, represents the bottom slope source term, , represents the bottom bed elevation, represents the hydrostatic pressure term in the case of a rectangular cross-section, and respectively represent the influences of the change in the width of the rectangular channel on the water depth and the discharge per unit width , represents the rate of change of the channel width in the channel length direction; Among them, represents the frictional slope gradient, which is calculated by the Manning formula as follows: （5） Among them, represents the Manning roughness coefficient, represents the hydraulic radius. When it is a rectangular cross-section, .

4. The prediction method for hydraulic parameters of dam overtopping breach according to claim 3, characterized in that, Before establishing the one-dimensional shallow water equation according to the calculated grid points after division, the method further includes: Set the basic assumption conditions of the one-dimensional shallow water equation, including: 1) The water flow participating in the operation is an incompressible fluid with a constant density; 2) The water flow is a gradually varied flow, and the water pressure satisfies the hydrostatic pressure distribution law in the vertical direction; 3) The wall friction resistance conforms to the Manning formula; 4) The bottom slope is adapted to the calculation of the one-dimensional shallow water equation.

5. The prediction method of the hydraulic parameters of dam overtopping and breach, according to claim 3, is characterized in that, Based on CFL The Courant number controls the time step of the one-dimensional shallow water equations, including: Based on CFL The Courant number limits the time step of the one-dimensional shallow water equations as follows: （6） （7） wherein, represents the depth-averaged cross-sectional velocity, represents the propagation velocity of the free surface gravity wave in still water.

6. The prediction method of the hydraulic parameters of dam overtopping and breach, according to claim 1, is characterized in that, In each time step calculation, it is necessary to discretely calculate the source term vector of the one-dimensional shallow water equation, including: In the discrete calculation of the topographic source term and the friction slope source term, the forward difference format is adopted in the predictor step, and the backward difference format is adopted in the corrector step for discrete calculation as follows: Predictor step source term discrete format: （15） Corrector step source term discrete format: （16） Among them, represents the time index, represents the spatial index in the direction, is the spatial step in the direction, , and are the average values of the single-width flow rate, water depth, and hydraulic radius at the node at time and the node respectively; In the discrete calculation caused by the change of the river width, the forward difference format is adopted in the predictor step, and the backward difference format is adopted in the corrector step for discrete calculation as follows: Predictor step source term discrete format: （17） （18） Corrector step source term discrete format: （19） （20）。 7. A prediction device for the hydraulic parameters of dam overtopping and breach, is characterized in that, including: An equation establishment module is used to perform grid division on a river channel based on the finite difference method and establish a one-dimensional shallow water equation according to the calculated grid points after division. Among them, the one-dimensional shallow water equation includes a conservation vector, a flux vector, and a source term vector. The variables of the conservation vector include water depth and discharge per unit width ; A parameter acquisition module, configured to obtain the basic parameters of the flux vector and the source term vector, and input the basic parameters into the one-dimensional shallow water equation to solve the flux vector and the source term vector respectively; A parameter prediction module, which is used to CFL control the time step of the one-dimensional shallow water equation based on the Courant number, and numerically discretize and solve the one-dimensional shallow water equation by using the differential format of the explicit MacCormark prediction-correction scheme to obtain the conservation vector at the next moment, so as to realize the prediction of the hydraulic parameters water depth and unit-width discharge ; Wherein, when numerically discretely solving the one-dimensional shallow water equation by using the explicit MacCormark predictor-corrector scheme difference format, it is necessary to introduce a TVD dissipation term near the shock wave to calculate the conservation vector at the next moment, and it is necessary to discretely calculate the source term vector of the one-dimensional shallow water equation in each time step calculation; Among them, the one-dimensional shallow water equations are numerically discretized and solved by using a differential format of the explicit MacCormark prediction-correction scheme to obtain the conservation vector at the next moment, including: The one-dimensional shallow water equations are numerically discretized and solved respectively based on the prediction step and the correction step in the explicit MacCormark scheme as follows: Prediction step: ; (8) Calibration step: ; (9) Among them, respectively represent the prediction step and the correction step, represents the unit node, and respectively represent the th time step and the th time step; According to the calculation results of the prediction step and the correction step, the conservation vector at the next moment is obtained as follows: （10）； Among them, the forward difference format is used for the spatial derivative in the prediction step, and the backward difference format is used for the spatial derivative in the correction step; Among them, a TVD dissipation term is introduced near the shock wave as follows: Among them, and respectively represent the dissipation matrix of the TVD term, and respectively represent the diffusion term matrix of the TVD term; The conservation vector at the next moment is calculated according to the TVD dissipation term as follows: ；（14） Among them, represents the water depth of the th unit node at the th time step, represents the water depth of the th unit node at the prediction step, represents the water depth of the th unit node at the correction step, is an introduced parameter, represents the discharge per unit width of the th unit node at the th time step, represents the discharge per unit width of the th unit node at the prediction step, represents the discharge per unit width of the th unit node at the correction step, represents the eigenvalue.

8. A computer device, characterized in that, It includes a memory, a processor, and a transceiver connected in sequence. Among them, the memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer programs and execute the prediction method for the hydraulic parameters of dam overtopping and breach as described in any one of claims 1 to 6.

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