Coupling method for 1D and 2D hydrodynamic models

Abstract

The present invention relates to the technical field of hydrodynamic simulation, and in particular to a coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model, comprising the following steps: S1, model preparation: determining a coupling region; S2, division of the coupling region: dividing the coupling region into a plurality of grid units; S3, adaptive boundary adjustment algorithm: dynamically adjusting the boundary position by using an adaptive boundary adjustment algorithm; S4, adaptive grid optimization: dynamically adjusting the scale and distribution density of the grid unit; S5, calculation of coupling parameters: repeatedly calculating the coupling parameters; S6, synchronization of time steps: performing data exchange and correction in the coupling region; S7, result output and analysis: outputting the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. The present invention avoids the instability phenomenon in numerical calculation, improves the overall calculation efficiency and accuracy, and thus better adapts to the complex hydrodynamic environment.

Description

Technical Field

[0001] The invention relates to the technical field of hydrodynamic simulation, and in particular to a coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model. Background Art

[0002] With the acceleration of urbanization and the continuous increase in water resource utilization, hydrodynamic models have been widely used in water conservancy projects, flood warning, environmental protection and other fields. Hydrodynamic models simulate the flow laws of water bodies and predict the changes in water speed, water level and water depth, providing a scientific basis for decision makers. At present, hydrodynamic models are mainly divided into one-dimensional hydrodynamic models and two-dimensional hydrodynamic models. One-dimensional hydrodynamic models are mainly used to describe longitudinally flowing water bodies such as rivers and channels, while two-dimensional hydrodynamic models are used to describe planar flowing water bodies such as lakes, estuaries and floodplains. Coupling one-dimensional and two-dimensional hydrodynamic models can make full use of the advantages of both and improve the accuracy and applicability of hydrodynamic simulation.

[0003] However, the existing technology has some shortcomings in the coupling process of one-dimensional and two-dimensional hydrodynamic models. First, the synchronization problem of time stepping has not been effectively solved, resulting in inconsistent calculation time steps of one-dimensional and two-dimensional models, affecting the accuracy of data exchange and model coupling. Secondly, the existing coupling methods often fail to fully consider the scale and distribution density of grid cells in the calculation and correction of boundary conditions, resulting in difficulty in achieving parameter balance in the coupling area. In addition, the existing technology lacks systematic error analysis and stability assessment in terms of result output and analysis, and cannot comprehensively evaluate the accuracy and reliability of the model.

[0004] In view of the shortcomings of the prior art, the present invention proposes a coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model to ensure the reliability and practicality of the calculation results and provide a scientific basis for hydrodynamic simulation and management. Summary of the invention

[0005] Based on the above objectives, the present invention provides a coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model.

[0006] The coupling method for the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model includes the following steps:

[0007] S1, model preparation: construct a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model, and define the corresponding calculation area and boundary conditions respectively, set the initial conditions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, and determine the coupling area of ​​the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model;

[0008] S2, division of coupling region: the coupling region is divided into several grid cells, each of which belongs to both the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. An exchange boundary is set in the coupling region to define the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model.

[0009] S3, adaptive boundary adjustment algorithm: using the adaptive boundary adjustment algorithm, the boundary positions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are dynamically adjusted according to the real-time monitored hydrodynamic data;

[0010] S4, Adaptive Grid Optimization: Dynamically adjust the scale and distribution density of grid cells according to the changes in flow velocity and water depth in the area, including:

[0011] S41, flow velocity and water depth monitoring: real-time monitoring of flow velocity and water depth in the coupling area;

[0012] S42, grid density adjustment: according to the monitored flow velocity and water depth, an adaptive grid optimization algorithm is used to dynamically adjust the scale and distribution density of the grid cells;

[0013] S43, grid optimization: optimizing the adjusted grid cells;

[0014] S5, calculation of coupling parameters: based on the adjusted boundary position and the scale and distribution density of the grid cells, within the coupling region, the boundary conditions of the two-dimensional hydrodynamic model are calculated according to the flow and water level data of the one-dimensional hydrodynamic model, and the boundary conditions of the one-dimensional hydrodynamic model are corrected according to the flow velocity and water depth data of the two-dimensional hydrodynamic model, and the coupling parameters are calculated repeatedly until the parameters of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model in the coupling region reach a balance;

[0015] S6, synchronization of time steps: set the time steps of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model so that the time steps of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are synchronized. In each time step, the one-dimensional hydrodynamic model is calculated first, then the two-dimensional hydrodynamic model is calculated, and finally the data is exchanged and corrected in the coupling area;

[0016] S7, result output and analysis: output the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, including flow, water level, flow velocity and water depth, and analyze the calculation results to evaluate the accuracy and stability of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model.

[0017] Optionally, the model preparation in S1 includes:

[0018] S11, construct a one-dimensional hydrodynamic model: use the implicit difference method as the numerical calculation method, define the calculation area of ​​the one-dimensional hydrodynamic model, and the calculation area is expressed in the coordinate system as ,in For the length of the channel, set the boundary conditions of the 1D hydrodynamic model, including the flow at the upstream boundary and the water level at the downstream boundary , expressed as:

[0019] ;

[0020] ;

[0021] in, and are the initial flow and water level, and For time The amount of change on

[0022] The one-dimensional hydrodynamic model is expressed as:

[0023] The mass conservation equation: ;

[0024] Momentum conservation equation: ;

[0025] in, is the cross-sectional area, For flow, For time, is the spatial coordinate, is the acceleration due to gravity, is the water level, is the cross-sectional flow coefficient;

[0026] S12, construct a two-dimensional hydrodynamic model: select the finite volume method as the numerical calculation method, define the calculation area of ​​the two-dimensional hydrodynamic model, and the calculation area is expressed in the coordinate system as and ,in and To calculate the length and width of the region, the boundary conditions of the two-dimensional hydrodynamic model are set, including the flow velocity and water depth at the region boundary, expressed as:

[0027] ;

[0028] ;

[0029] ;

[0030] in, yes The velocity component in the direction, yes The velocity component in the direction, , and are the initial flow velocity and water depth, , and For time The amount of change on

[0031] The two-dimensional hydrodynamic model is expressed as:

[0032] The mass conservation equation: ;

[0033] Momentum conservation equation:

[0034] exist direction: ;

[0035] exist direction: ;

[0036] in, For water depth, for The velocity component in the direction, for The velocity component in the direction, is the acceleration due to gravity, is the water level, and for and Directional body forces;

[0037] S13, setting initial conditions: according to actual hydrodynamic observation data, including flow rate, flow velocity, water level and water depth, setting initial flow rate and initial water level for the one-dimensional hydrodynamic model, and setting initial flow velocity and initial water depth for the two-dimensional hydrodynamic model;

[0038] S14, determine the coupling region: the coupling region is the overlapping region of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. The definition of the coupling region is expressed by a coordinate system as follows:

[0039] ;

[0040] ;

[0041] in, , , and are the boundary coordinates of the coupling region.

[0042] Optionally, the division of the coupling area in S2 includes:

[0043] S21, coupled region meshing: The two-dimensional mesh cells are rectangular or polygonal mesh cells. The calculation of mesh cell area and volume includes:

[0044] S211, Calculation of area and volume of rectangular grid cells:

[0045] ;

[0046] ;

[0047] in, and are the area and volume of the rectangular grid cell, is a rectangular grid cell in The length of the direction, is a rectangular grid cell in The width of the direction, is the water depth within the grid cell;

[0048] S212, calculation of area and volume of polygonal mesh elements:

[0049] ;

[0050] ;

[0051] in, and are the area and volume of the polygonal mesh unit, is the polygonal mesh unit The coordinates of the vertices, is the number of vertices of the polygonal mesh unit;

[0052] S22, grid cell calculation: The change of conserved quantity is represented by boundary flux, including:

[0053] S221, Flux of the mass conservation equation : ;

[0054] in, For water depth, For water depth and The product of the directional velocities, For water depth and The product of directional velocities;

[0055] S222, Flux of the Momentum Conservation Equation and : ;

[0056] in, For water depth and The product of the directional velocities, is the momentum flux in Changes in direction, For water depth and Direction speed and The product of the directional velocities, For water depth and The product of the directional velocities, is the momentum flux in changes in direction;

[0057] S223, discretized form: ;

[0058] in, is the volume mean of the conservative variable, is the volume of the grid cell, is the boundary flux, is the boundary area, is the source term;

[0059] S23, set exchange boundary: set exchange boundary in the coupling region to define the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as:

[0060] ;

[0061] in, is the traffic at the exchange boundary, and are the flow rates calculated by the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, is the adjustment factor;

[0062] S24, definition of interaction region: determine the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. The hydrodynamic observation data in the interaction region are weighted averaged according to the calculation results of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as:

[0063] ;

[0064] in, is the hydrodynamic observation data of the interaction area, and are the parameters calculated by the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, is the weight coefficient.

[0065] Optionally, the adaptive boundary adjustment algorithm in S3 includes:

[0066] S31, real-time monitoring of hydrodynamic data: using sensors and monitoring equipment to obtain real-time hydrodynamic observation data in the coupling area, including flow, velocity, water level and water depth;

[0067] S32, data preprocessing: preprocessing the real-time hydrodynamic observation data, including noise removal, outlier processing and data interpolation;

[0068] S33, boundary adjustment criterion: according to the pre-processed hydrodynamic observation data, the boundary adjustment criterion is set based on the change of flow, water level, flow velocity or water depth. When a certain hydrodynamic observation data exceeds the preset threshold, the boundary adjustment is triggered, which is expressed as:

[0069] or or or or ;

[0070] in, , , and , They represent the changes in flow, water level, flow velocity, and water depth respectively. , , and , is the corresponding threshold;

[0071] S34, boundary position adjustment: According to the boundary adjustment criterion, the boundary positions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are dynamically adjusted using an adaptive boundary adjustment algorithm, which is expressed as:

[0072] ;

[0073] ;

[0074] in, and are the current boundary positions. Coordinates and coordinate, and are the adjusted boundary positions, The boundary position is The amount of adjustment in direction, The boundary position is The amount of adjustment in direction;

[0075] S35, boundary condition update: according to the adjusted boundary position, the boundary conditions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are recalculated and updated, which are expressed as:

[0076] ;

[0077] ;

[0078] ;

[0079] ;

[0080] ;

[0081] in, The updated upstream boundary is at time of traffic, is the initial flow rate, For in time and the new border position The flow change at The updated downstream boundary is at time The water level, is the initial water level, For in time and the new border position The water level change at The updated upstream boundary is at time of Direction speed, For initial Direction speed, For in time and the new border position Where Directional speed change, The updated upstream boundary is at time of Direction speed, For initial Direction speed, For in time and the new border position Where Directional speed change, The updated upstream boundary is at time The depth of water, is the initial water depth, For in time and the new border position The change in water depth.

[0082] Optionally, the flow velocity and water depth monitoring in S41 includes:

[0083] S411, data monitoring: arranging flow velocity sensors and water depth sensors in the coupling area to monitor the flow velocity and water depth in the coupling area in real time;

[0084] S412, preliminary data processing: use a low-pass filter to remove noise and outliers from the monitored flow velocity and water depth.

[0085] Optionally, the adaptive mesh optimization algorithm in S42 adopts a gradient-based adaptive mesh generation algorithm, and the gradient-based adaptive mesh generation algorithm includes:

[0086] S421, calculate flow velocity and water depth gradient: calculate the spatial gradient of flow velocity and water depth, expressed as:

[0087] ;

[0088] ;

[0089] in, is the flow velocity gradient, For flow rate The partial derivative of the direction, For flow rate The partial derivative of the direction, is the water depth gradient, For the water depth The partial derivative of the direction, For the water depth Partial derivatives of direction;

[0090] S422, introduce weighting factors: introduce weighting factors for flow velocity and water depth gradient, expressed as:

[0091] ;

[0092] ;

[0093] in, and is the weight factor;

[0094] S423, dynamically adjust the grid density: dynamically adjust the scale and distribution density of the grid cells according to the calculated weighted gradient value, expressed as:

[0095] For a refined mesh: ;

[0096] For a coarse mesh: ;

[0097] in, The adjusted grid cells are The length of the direction, The original grid cell is The length of the direction, is the weighted velocity gradient, is the threshold of flow velocity gradient, The adjusted grid cells are The length of the direction, The original grid cell is The length of the direction, is the weighted water depth gradient, is the threshold of water depth gradient.

[0098] Optionally, the grid optimization in S43 includes:

[0099] S431, initial grid adjustment: After adjusting the grid density, make a preliminary adjustment to the grid cells, expressed as:

[0100] ;

[0101] in, For the The adjusted position of the nodes, is the position of the adjacent node, is the number of adjacent nodes;

[0102] S432, Mesh Quality Assessment: Evaluate the quality of each mesh cell, using mesh quality metrics such as shape parameters to assess the shape and size of the mesh, expressed as:

[0103] ;

[0104] in, For the The quality index of each grid cell is is a constant parameter, For the The area of ​​a grid cell, For the The length of the side, is the number of edges of the grid cell;

[0105] S433, Laplace smoothing algorithm: Use the Laplace smoothing algorithm to optimize the mesh nodes and adjust the node positions to improve the mesh quality, expressed as:

[0106] ;

[0107] in, For the The optimal location of the nodes, is the current node position, is the position of the adjacent node, is the number of adjacent nodes, is the smoothing factor;

[0108] S434, iterative optimization: The mesh optimization process is iterated multiple times, expressed as:

[0109] ;

[0110] in, For the The node in The position after iterations, For the adjacent nodes in The position after iterations.

[0111] Optionally, the calculation of the coupling parameters in S5 includes:

[0112] S51, Calculation of boundary conditions from one-dimensional hydrodynamic model to two-dimensional hydrodynamic model: Based on the adjusted boundary position and the scale and distribution density of the grid cells, the boundary conditions of the two-dimensional hydrodynamic model are calculated according to the flow and water level of the one-dimensional hydrodynamic model, expressed as:

[0113] ;

[0114] ;

[0115] in, and are the flow and water level boundary conditions of the two-dimensional hydrodynamic model, and are the flow and water level of the one-dimensional hydrodynamic model, and are the cross-sectional areas of the two-dimensional hydrodynamic model and the one-dimensional hydrodynamic model, respectively. is the adjusted water level difference;

[0116] S52, 2D hydrodynamic model calculation: Using the calculated boundary conditions, calculate the flow velocity and water depth in the 2D hydrodynamic model, expressed as:

[0117] ;

[0118] in, is the flow rate, For flow, is the cross-sectional area;

[0119] ;

[0120] in, For water depth, For flow, is the flow rate, is the fluid width;

[0121] S53, Boundary condition correction from two-dimensional hydrodynamic model to one-dimensional hydrodynamic model: According to the flow velocity and water depth of the two-dimensional hydrodynamic model, the boundary condition of the one-dimensional hydrodynamic model is corrected, which is expressed as:

[0122] ;

[0123] ;

[0124] in, and are the flow and water level boundary conditions of the modified one-dimensional hydrodynamic model, is the flow correction value;

[0125] S54, repeated calculation of coupling parameters: the calculation of coupling parameters is repeated until the parameters of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model in the coupling region reach equilibrium, and the equilibrium condition is expressed as:

[0126] ;

[0127] ;

[0128] in, and are the thresholds for flow and water level balance conditions, respectively.

[0129] Optionally, the synchronization of the time step in S6 includes:

[0130] S61, setting of time step: setting the time step of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model so that the time steps of the two models are synchronized, which is expressed as:

[0131] ;

[0132] in, and are the time steps of the one-dimensional and two-dimensional hydrodynamic models, respectively. To satisfy The time step of the condition, is the time step that satisfies the stability condition;

[0133] S62, Condition: Calculation satisfies The time step of the condition is expressed as:

[0134] ;

[0135] in, is the grid unit length, is the flow rate, is the wave speed;

[0136] S63, Stability Condition: Calculate the time step that satisfies the stability condition, expressed as:

[0137] ;

[0138] in, is the grid unit length, is the kinematic viscosity coefficient;

[0139] S64, time-stepping synchronous calculation: In each time step, the one-dimensional hydrodynamic model is calculated first, then the two-dimensional hydrodynamic model is calculated, and finally the data is exchanged and corrected in the coupling area, which is expressed as:

[0140] Compute a one-dimensional hydrodynamic model: ;

[0141] in, is the flow rate of the one-dimensional hydrodynamic model, is the water level of the one-dimensional hydrodynamic model;

[0142] Compute the 2D hydrodynamic model:

[0143] ;

[0144] ;

[0145] ;

[0146] Data exchange and correction:

[0147] ;

[0148] ;

[0149] in, is the flow rate of the one-dimensional hydrodynamic model, is the water level of the one-dimensional hydrodynamic model, is the water depth of the two-dimensional hydrodynamic model, For a two-dimensional hydrodynamic model The velocity component in the direction, For a two-dimensional hydrodynamic model The velocity component in the direction, is the water level of the two-dimensional hydrodynamic model, For a two-dimensional hydrodynamic model The body force in the direction For a two-dimensional hydrodynamic model The body force in the direction is the acceleration due to gravity.

[0150] Optionally, the result output and analysis in S7 includes:

[0151] S71, result output: output the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as:

[0152] ;

[0153] ;

[0154] ;

[0155] ;

[0156] S72, calculation result analysis: based on the output flow, water level, flow velocity and water depth, generate a time series graph and a spatial distribution graph, expressed as:

[0157] ;

[0158] ;

[0159] S73, accuracy assessment: The error analysis method is used to evaluate the calculation accuracy of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, which is expressed as:

[0160] ;

[0161] ;

[0162] ;

[0163] ;

[0164] in, and are the observed flow, water level, flow velocity and water depth, respectively;

[0165] S74, Stability evaluation: The stability of the model is evaluated by calculating the change in the results of the model at different time steps and different initial conditions, expressed as:

[0166] ;

[0167] ;

[0168] ;

[0169] ;

[0170] in, , , , They are the stability evaluation indicators of flow, water level, flow velocity and water depth. , , , They are flow rate, water level, flow velocity, water depth and time. The rate of change.

[0171] Beneficial effects of the present invention:

[0172] The present invention enables one-dimensional and two-dimensional hydrodynamic models to be calculated within the same time step by setting a synchronized time step and dynamically adjusting the boundary position, thereby ensuring data consistency and calculation stability. By satisfying CFL conditions and stability conditions, instability in numerical calculations is avoided, and the overall calculation efficiency and accuracy are improved, thereby better adapting to complex hydrodynamic environments.

[0173] The present invention dynamically calculates and corrects the boundary conditions of one-dimensional and two-dimensional hydrodynamic models by adjusting the boundary positions and the scale and distribution density of the grid units to ensure that the parameters in the coupling area are balanced. By introducing an improved gradient-based adaptive grid optimization algorithm, the grid density can be flexibly adjusted to improve the calculation accuracy and efficiency, avoid excessive distortion of the grid units, and enhance the stability and responsiveness of the model under complex hydrodynamic conditions.

[0174] The present invention evaluates the accuracy and stability of the model through analysis of time series and spatial distribution diagrams. Error analysis and stability evaluation provide quantitative evaluation indicators to ensure the reliability and practicality of the calculation results, thereby providing a scientific basis for actual hydrodynamic simulation and management and effectively improving the application value of the model. BRIEF DESCRIPTION OF THE DRAWINGS

[0175] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0176] Figure 1 A schematic diagram of a coupling method flow chart of an embodiment of the present invention;

[0177] Figure 2 Schematic diagram of adaptive grid optimization according to an embodiment of the present invention. DETAILED DESCRIPTION

[0178] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0179] It should be noted that the references to "one embodiment", "embodiment", "exemplary embodiments", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0180] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0181] like Figure 1-Figure 2 As shown, the coupling method for the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model includes the following steps:

[0182] S1, model preparation: construct a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model, and define the corresponding calculation area and boundary conditions respectively, set the initial conditions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, and determine the coupling area of ​​the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model;

[0183] S2, division of coupling region: the coupling region is divided into several grid cells, each of which belongs to both the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. An exchange boundary is set in the coupling region to define the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model.

[0184] S3, Adaptive boundary adjustment algorithm: Using the adaptive boundary adjustment algorithm, the boundary positions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are dynamically adjusted according to the real-time monitored hydrodynamic data to ensure that the flow characteristics in the coupling area are consistent with the actual situation;

[0185] S4, Adaptive Grid Optimization: Dynamically adjust the scale and distribution density of grid cells according to the changes in flow velocity and water depth in the area to improve calculation accuracy and efficiency, including:

[0186] S41, flow velocity and water depth monitoring: real-time monitoring of flow velocity and water depth in the coupling area;

[0187] S42, grid density adjustment: according to the monitored flow velocity and water depth, an adaptive grid optimization algorithm is used to dynamically adjust the scale and distribution density of grid cells, increase the grid density in areas where flow velocity and water depth change dramatically, and reduce the grid density in areas where the changes are stable;

[0188] S43, grid optimization: optimizing the adjusted grid cells to ensure the rationality of the shape and size of the grid cells;

[0189] S5, calculation of coupling parameters: based on the adjusted boundary position and the scale and distribution density of the grid cells, within the coupling region, the boundary conditions of the two-dimensional hydrodynamic model are calculated according to the flow and water level data of the one-dimensional hydrodynamic model, and the boundary conditions of the one-dimensional hydrodynamic model are corrected according to the flow velocity and water depth data of the two-dimensional hydrodynamic model, and the coupling parameters are calculated repeatedly until the parameters of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model in the coupling region reach a balance;

[0190] S6, synchronization of time steps: set the time steps of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model so that the time steps of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are synchronized. In each time step, the one-dimensional hydrodynamic model is calculated first, then the two-dimensional hydrodynamic model is calculated, and finally the data is exchanged and corrected in the coupling area;

[0191] S7, result output and analysis: output the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, including flow, water level, flow velocity and water depth, and analyze the calculation results to evaluate the accuracy and stability of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model;

[0192] Through the above steps, efficient coupling of one-dimensional and two-dimensional hydrodynamic models is achieved, which significantly improves the calculation accuracy and efficiency, ensures the consistency of flow characteristics in the coupling area with the actual situation, and finally outputs more accurate and reliable hydrodynamic model calculation results.

[0193] Model preparation in S1 includes:

[0194] S11, construct a one-dimensional hydrodynamic model: implicit difference method is selected as the numerical calculation method to ensure the stability and efficiency of the calculation. The calculation area of ​​the one-dimensional hydrodynamic model is defined, which is usually a narrow and long water body such as a river or channel. The calculation area is expressed in the coordinate system as ,in For the length of the channel, set the boundary conditions of the 1D hydrodynamic model, including the flow at the upstream boundary and the water level at the downstream boundary , expressed as:

[0195] ;

[0196] ;

[0197] in, and are the initial flow and water level, and For time The amount of change on

[0198] The one-dimensional hydrodynamic model is expressed as:

[0199] The mass conservation equation: ;

[0200] Momentum conservation equation: ;

[0201] in, is the cross-sectional area, For flow, For time, is the spatial coordinate, is the acceleration due to gravity, is the water level, is the cross-sectional flow coefficient;

[0202] S12, construct a two-dimensional hydrodynamic model: the finite volume method is used as the numerical calculation method to accurately capture the flow characteristics of complex terrain. The calculation area of ​​the two-dimensional hydrodynamic model is defined, which is usually a complex terrain water body such as a lake, wetland or floodplain. The calculation area is expressed in a coordinate system as and ,in and To calculate the length and width of the region, the boundary conditions of the two-dimensional hydrodynamic model are set, including the flow velocity and water depth at the region boundary, expressed as:

[0203] ;

[0204] ;

[0205] ;

[0206] in, yes The velocity component in the direction, yes The velocity component in the direction, , and are the initial flow velocity and water depth, , and For time The amount of change on

[0207] The two-dimensional hydrodynamic model is expressed as:

[0208] The mass conservation equation: ;

[0209] Momentum conservation equation:

[0210] exist direction: ;

[0211] exist direction: ;

[0212] in, For water depth, for The velocity component in the direction, for The velocity component in the direction, is the acceleration due to gravity, is the water level, and for and Directional body forces;

[0213] S13, setting initial conditions: according to actual hydrodynamic observation data, including flow rate, flow velocity, water level and water depth, setting initial flow rate and initial water level for the one-dimensional hydrodynamic model, and setting initial flow velocity and initial water depth for the two-dimensional hydrodynamic model;

[0214] S14, determine the coupling area: The coupling area is the overlapping area of ​​the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, which is usually selected at the connection between rivers and lakes, rivers and wetlands, etc. The definition of the coupling area is expressed by the coordinate system as follows:

[0215] ;

[0216] ;

[0217] in, , , and is the boundary coordinate of the coupling region;

[0218] Through the above content, not only the calculation accuracy and stability of the model are improved, but also a solid foundation is laid for the subsequent coupling process, especially when dealing with complex terrain and extreme hydrological events, it can more effectively simulate the actual hydrodynamic conditions.

[0219] The initial conditions set in S13 specifically include:

[0220] S131, Data Collection: Collect actual hydrodynamic observation data of the study area, including flow, velocity, water level and water depth, through hydrological station monitoring data, remote sensing data and satellite images;

[0221] S132, data preprocessing: preprocessing the collected observation data, including data cleaning, interpolation and filtering;

[0222] S133, initial flow and water level setting: select the flow observation data at the upstream boundary of the study area as the initial flow, and select the water level observation data at the downstream boundary of the study area as the initial water level;

[0223] S134, initial flow velocity and water depth settings: Determine the initial flow velocity and water depth based on the flow velocity observation data in the area. Direction and The velocity component in the direction is taken as the initial flow velocity, and the water depth observation data in the area is taken as the initial water depth.

[0224] The division of the coupling region in S2 includes:

[0225] S21, coupled region meshing: The two-dimensional mesh cells are rectangular or polygonal mesh cells. The calculation of mesh cell area and volume includes:

[0226] S211, Calculation of area and volume of rectangular grid cells:

[0227] ;

[0228] ;

[0229] in, and are the area and volume of the rectangular grid cell, is a rectangular grid cell in The length of the direction, is a rectangular grid cell in The width of the direction, is the water depth within the grid cell;

[0230] S212, calculation of area and volume of polygonal mesh elements:

[0231] ;

[0232] ;

[0233] in, and are the area and volume of the polygonal mesh unit, is the polygonal mesh unit The coordinates of the vertices, is the number of vertices of the polygonal mesh unit;

[0234] S22, grid cell calculation: The change of conserved quantity is represented by boundary flux, including:

[0235] S221, Flux of the mass conservation equation : ;

[0236] in, For water depth, For water depth and The product of the directional velocities, indicating the mass flux in The direction component, For water depth and The product of the directional velocities, indicating the mass flux in Directional component;

[0237] S222, Flux of the Momentum Conservation Equation and : ;

[0238] in, For water depth and The product of the direction velocities, indicating the momentum flux in The direction component, is the momentum flux in The change in direction includes the kinetic energy term and the water pressure term. For water depth and Direction speed and The product of the direction velocities represents the momentum flux in The weight in direction, For water depth and The product of the direction velocities, indicating the momentum flux in The direction component, is the momentum flux in Changes in direction, including kinetic energy terms and water pressure terms;

[0239] S223, discretized form: ;

[0240] in, is the volume mean of the conservative variable, is the volume of the grid cell, is the boundary flux, which represents the flux through the grid cell boundary The flux, is the boundary area, representing the grid cell boundary The area of is the source term, which represents the contribution to the conservative quantity in the grid cell;

[0241] S23, set exchange boundary: set the exchange boundary in the coupling region to define the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. The exchange boundary refers to the boundary position for data exchange between the one-dimensional and two-dimensional models, which is expressed as:

[0242] ;

[0243] in, is the traffic at the exchange boundary, and are the flow rates calculated by the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, It is the adjustment coefficient, which usually takes a value between 0 and 1;

[0244] S24, definition of interaction region: determine the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, that is, the overlapping part of the two models in the coupling region. The definition of the interaction region needs to consider the calculation results of the two models in the same time step, so that data exchange and coupling calculation can proceed smoothly. The hydrodynamic observation data in the interaction region are weighted averaged according to the calculation results of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model to ensure the consistency of the calculation, which is expressed as:

[0245] ;

[0246] in, is the hydrodynamic observation data of the interaction area, and are the parameters calculated by the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, is the weight coefficient;

[0247] Through the above contents, the accuracy and stability of data exchange and interaction between the two models in this area are ensured, which not only improves the calculation accuracy and efficiency, but also can more realistically simulate the flow characteristics under complex hydrodynamic conditions, and is suitable for the simulation and analysis of various complex terrains and extreme hydrological events.

[0248] The adaptive boundary adjustment algorithms in S3 include:

[0249] S31, real-time monitoring of hydrodynamic data: using sensors and monitoring equipment to obtain real-time hydrodynamic observation data in the coupling area, including flow, velocity, water level and water depth;

[0250] S32, data preprocessing: preprocessing the real-time hydrodynamic observation data, including noise removal, outlier processing and data interpolation, to ensure the accuracy and continuity of the data;

[0251] S33, boundary adjustment criterion: according to the pre-processed hydrodynamic observation data, the boundary adjustment criterion is set based on the change of flow, water level, flow velocity or water depth. When a certain hydrodynamic observation data exceeds the preset threshold, the boundary adjustment is triggered, which is expressed as:

[0252] or or or or ;

[0253] in, , , and , They represent the changes in flow, water level, flow velocity, and water depth respectively. , , and , is the corresponding threshold;

[0254] S34, boundary position adjustment: According to the boundary adjustment criterion, the boundary positions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are dynamically adjusted using an adaptive boundary adjustment algorithm, which is expressed as:

[0255] ;

[0256] ;

[0257] in, and are the current boundary positions. Coordinates and coordinate, and are the adjusted boundary positions, The boundary position is The amount of adjustment in direction, The boundary position is The amount of adjustment in direction;

[0258] S35, boundary condition update: according to the adjusted boundary position, the boundary conditions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are recalculated and updated, which are expressed as:

[0259] ;

[0260] ;

[0261] ;

[0262] ;

[0263] ;

[0264] in, The updated upstream boundary is at time of traffic, is the initial flow rate, For in time and the new border position The flow change at The updated downstream boundary is at time The water level, is the initial water level, For in time and the new border position The water level change at The updated upstream boundary is at time of Direction speed, For initial Direction speed, For in time and the new border position Where Directional speed change, The updated upstream boundary is at time of Direction speed, For initial Direction speed, For in time and the new border position Where Directional speed change, The updated upstream boundary is at time The depth of water, is the initial water depth, For in time and the new border position The change of water depth at

[0265] Through the above content, not only the accuracy and stability of the model calculation are improved, but also more accurate simulation results can be provided under extreme hydrological events and complex terrain conditions, which is suitable for hydrodynamic research and management in various practical application scenarios.

[0266] Threshold , , and The determination includes:

[0267] Data statistical analysis: Statistical analysis of historical hydrodynamic observation data was performed to calculate the mean and standard deviation of flow, water level, and flow velocity, expressed as:

[0268] ;

[0269] ;

[0270] in, is the hydrodynamic observation data, is the number of observations;

[0271] Threshold setting: Based on the statistical analysis results and model requirements, the threshold is determined by adding a certain multiple of the standard deviation to the mean, expressed as:

[0272] ;

[0273] ;

[0274] ;

[0275] ;

[0276] ;

[0277] in, , , and , are the mean values ​​of flow rate, water level, flow velocity and water depth respectively. , , and , are the standard deviations of flow, water level, flow velocity and water depth, respectively. is a constant, ranging from 1 to 3;

[0278] Experimentation and adjustment: In practical applications, the threshold is adjusted through multiple experiments to ensure the stability and accuracy of the model under different conditions. Based on the experimental results, the threshold is fine-tuned until the optimal threshold setting is found.

[0279] Flow rate and water depth monitoring in S41 includes:

[0280] S411, data monitoring: flow velocity sensors and water depth sensors are arranged in the coupling area to ensure the comprehensiveness and representativeness of the monitoring data, and to monitor the flow velocity and water depth in the coupling area in real time;

[0281] S412, preliminary data processing: Use a low-pass filter to remove noise and outliers from the monitored flow velocity and water depth to ensure the continuity and accuracy of the data.

[0282] The adaptive mesh optimization algorithm in S42 adopts a gradient-based adaptive mesh generation algorithm. The gradient-based adaptive mesh generation algorithm includes:

[0283] S421, calculate flow velocity and water depth gradient: calculate the spatial gradient of flow velocity and water depth as the basis for adjusting the grid density, expressed as:

[0284] ;

[0285] ;

[0286] in, is the flow velocity gradient, For flow rate The partial derivative of the direction, For flow rate The partial derivative of the direction, is the water depth gradient, For the water depth The partial derivative of the direction, For the water depth Partial derivatives of direction;

[0287] S422, introduce weighting factors: introduce weighting factors for flow velocity and water depth gradient to make grid adjustment more flexible, expressed as:

[0288] ;

[0289] ;

[0290] in, and is the weight factor to balance the effects of flow velocity and water depth;

[0291] S423, dynamically adjust the grid density: dynamically adjust the scale and distribution density of the grid cells according to the calculated weighted gradient value, expressed as:

[0292] For a refined mesh: ;

[0293] For a coarse mesh: ;

[0294] in, The adjusted grid cells are The length of the direction, The original grid cell is The length of the direction, is the weighted velocity gradient, is the threshold of flow velocity gradient, The adjusted grid cells are The length of the direction, The original grid cell is The length of the direction, is the weighted water depth gradient, is the threshold of water depth gradient;

[0295] Through the above contents, the calculation accuracy and efficiency are improved, while the rationality of the shape and size of the grid units is maintained and excessive distortion is avoided, making it more suitable for simulation and analysis under complex hydrodynamic conditions and improving the stability and responsiveness of the model.

[0296] Mesh optimization in S43 includes:

[0297] S431, initial grid adjustment: After adjusting the grid density, the grid cells are initially adjusted to eliminate obvious grid distortion, expressed as:

[0298] ;

[0299] in, For the The adjusted position of the nodes, is the position of the adjacent node, is the number of adjacent nodes;

[0300] S432, Mesh Quality Assessment: Evaluate the quality of each mesh cell, using mesh quality metrics such as shape parameters to assess the shape and size of the mesh, expressed as:

[0301] ;

[0302] in, For the The quality index of each grid cell is is a constant parameter, whose value is , For the The area of ​​a grid cell, For the The length of the side, is the number of edges of the mesh unit. For a triangular mesh unit ;

[0303] S433, Laplace smoothing algorithm: Use the Laplace smoothing algorithm to optimize the mesh nodes and adjust the node positions to improve the mesh quality, expressed as:

[0304] ;

[0305] in, For the The optimal location of the nodes, is the current node position, is the position of the adjacent node, is the number of adjacent nodes, is the smoothing factor, with a value between 0 and 1;

[0306] S434, iterative optimization: the mesh optimization process is iterated multiple times to gradually improve the mesh quality and ensure that the final mesh shape and size meet the requirements, expressed as:

[0307] ;

[0308] in, For the The node in The position after iterations, For the adjacent nodes in The position after iterations;

[0309] Through the above steps, the adjusted grid units can be further optimized, the shape and size of the grid can be improved, the calculation accuracy and stability can be improved, and it can be more suitable for complex hydrodynamic simulation environments.

[0310] The calculation of coupling parameters in S5 includes:

[0311] S51, Calculation of boundary conditions from one-dimensional hydrodynamic model to two-dimensional hydrodynamic model: Based on the adjusted boundary position and the scale and distribution density of the grid cells, the boundary conditions of the two-dimensional hydrodynamic model are calculated according to the flow and water level of the one-dimensional hydrodynamic model, expressed as:

[0312] ;

[0313] ;

[0314] in, and are the flow and water level boundary conditions of the two-dimensional hydrodynamic model, and are the flow and water level of the one-dimensional hydrodynamic model, and are the cross-sectional areas of the two-dimensional hydrodynamic model and the one-dimensional hydrodynamic model, respectively. is the adjusted water level difference;

[0315] S52, 2D hydrodynamic model calculation: Using the calculated boundary conditions, calculate the flow velocity and water depth in the 2D hydrodynamic model, expressed as:

[0316] ;

[0317] in, is the flow rate, For flow, is the cross-sectional area;

[0318] ;

[0319] in, For water depth, For flow, is the flow rate, is the fluid width;

[0320] S53, Boundary condition correction from two-dimensional hydrodynamic model to one-dimensional hydrodynamic model: According to the flow velocity and water depth of the two-dimensional hydrodynamic model, the boundary condition of the one-dimensional hydrodynamic model is corrected, which is expressed as:

[0321] ;

[0322] ;

[0323] in, and are the flow and water level boundary conditions of the modified one-dimensional hydrodynamic model, is the flow correction value;

[0324] S54, repeated calculation of coupling parameters: the calculation of coupling parameters is repeated until the parameters of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model in the coupling region reach equilibrium, and the equilibrium condition is expressed as:

[0325] ;

[0326] ;

[0327] in, and are the thresholds of flow and water level balance conditions, respectively;

[0328] Thresholds for flow and water level balance conditions and By analyzing historical observation data, the standard deviation of flow and water level is calculated, and the threshold is set as a multiple of the standard deviation, expressed as:

[0329] ;

[0330] ;

[0331] in, and are the standard deviations of flow and water level, respectively, and It is an empirical coefficient, and its value ranges from 1 to 3.

[0332] Through the above steps, the overall calculation accuracy and stability of the model are improved, which can more effectively handle complex hydrodynamic situations and ensure the accuracy and reliability of the simulation results.

[0333] Synchronization of time steps in S6 includes:

[0334] S61, setting of time step: setting the time step of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model so that the time steps of the two models are synchronized, which is expressed as:

[0335] ;

[0336] in, and are the time steps of the one-dimensional and two-dimensional hydrodynamic models, respectively. To satisfy The time step of the condition, is the time step that satisfies the stability condition;

[0337] S62, Condition: Calculation satisfies The time step of the condition to ensure numerical stability is expressed as:

[0338] ;

[0339] in, is the grid unit length, is the flow rate, is the wave speed, ,in is the acceleration due to gravity, for water depth;

[0340] S63, Stability Condition: Calculate the time step that satisfies the stability condition to ensure the stability of the numerical solution, expressed as:

[0341] ;

[0342] in, is the grid unit length, is the kinematic viscosity coefficient;

[0343] S64, time-stepping synchronous calculation: In each time step, the one-dimensional hydrodynamic model is calculated first, then the two-dimensional hydrodynamic model is calculated, and finally the data is exchanged and corrected in the coupling area, which is expressed as:

[0344] Compute a one-dimensional hydrodynamic model: ;

[0345] in, is the flow rate of the one-dimensional hydrodynamic model, is the water level of the one-dimensional hydrodynamic model;

[0346] Compute the 2D hydrodynamic model:

[0347] ;

[0348] ;

[0349] ;

[0350] Data exchange and correction:

[0351] ;

[0352] ;

[0353] in, is the flow rate of the one-dimensional hydrodynamic model, is the water level of the one-dimensional hydrodynamic model, is the water depth of the two-dimensional hydrodynamic model, For a two-dimensional hydrodynamic model The velocity component in the direction, For a two-dimensional hydrodynamic model The velocity component in the direction, is the water level of the two-dimensional hydrodynamic model, For a two-dimensional hydrodynamic model The body force in the direction For a two-dimensional hydrodynamic model The body force in the direction is the acceleration due to gravity;

[0354] Through the above contents, the consistency and coordination of the calculations of the two models are improved, and the stability and accuracy of the numerical solution are ensured, thereby providing more reliable and accurate simulation results in complex hydrodynamic environments. In addition, by satisfying the CFL conditions and stability conditions, the instability phenomenon in the numerical calculation can be effectively avoided and the overall calculation efficiency of the model can be improved.

[0355] Result output and analysis in S7 include:

[0356] S71, result output: output the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as:

[0357] ;

[0358] ;

[0359] ;

[0360] ;

[0361] S72, calculation result analysis: based on the output flow, water level, flow velocity and water depth, generate a time series graph and a spatial distribution graph, expressed as:

[0362] ;

[0363] ;

[0364] S73, accuracy assessment: The error analysis method is used to evaluate the calculation accuracy of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, which is expressed as:

[0365] ;

[0366] ;

[0367] ;

[0368] ;

[0369] in, and are the observed flow, water level, flow velocity and water depth, respectively;

[0370] S74, Stability evaluation: The stability of the model is evaluated by calculating the change in the results of the model at different time steps and different initial conditions, expressed as:

[0371] ;

[0372] ;

[0373] ;

[0374] ;

[0375] in, , , , They are the stability evaluation indicators of flow, water level, flow velocity and water depth. , , , They are flow rate, water level, flow velocity, water depth and time. The rate of change of

[0376] Through the above content, the response of the model under different conditions can be detected to ensure the stability of the calculation process, which not only improves the reliability and practicality of the model, but also provides a scientific basis for further optimization and application.

[0377] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0378] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model, characterized in that: The following steps are involved: S1, model preparation: construct a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model, and define the corresponding calculation area and boundary conditions respectively, set the initial conditions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, and determine the coupling area of ​​the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model; S2, division of coupling region: the coupling region is divided into several grid cells, each of which belongs to both the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. An exchange boundary is set in the coupling region to define the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. S3, adaptive boundary adjustment algorithm: using the adaptive boundary adjustment algorithm, dynamically adjusting the boundary position of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model according to the real-time monitored hydrodynamic data, the adaptive boundary adjustment algorithm includes: S31, real-time monitoring of hydrodynamic data: using sensors and monitoring equipment to obtain real-time hydrodynamic observation data in the coupling area, including flow, velocity, water level and water depth; S32, data preprocessing: preprocessing the real-time hydrodynamic observation data, including noise removal, outlier processing and data interpolation; S33, boundary adjustment criterion: according to the pre-processed hydrodynamic observation data, the boundary adjustment criterion is set based on the change of flow, water level, flow velocity or water depth. When a certain hydrodynamic observation data exceeds the preset threshold, the boundary adjustment is triggered, which is expressed as: ΔQ>∈ Q Or ΔH>∈ H Or Δu>∈ u or Δv>∈ v or Δh>∈ h ; Among them, ΔQ, ΔH, Δu and Δv, Δh represent the changes in flow, water level, flow velocity, and water depth, respectively, ∈ Q ,∈ H ,∈ u and ∈ v ,∈ h is the corresponding threshold; S34, boundary position adjustment: According to the boundary adjustment criterion, the boundary positions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are dynamically adjusted using an adaptive boundary adjustment algorithm, which is expressed as: x b '=x b +Δx b ; y b '=y b +Δy b ; Among them, x b and b are the x and y coordinates of the current boundary position, respectively. b ' and y b ' are the adjusted boundary positions, Δx b is the adjustment amount of the boundary position in the x direction, Δy b is the adjustment amount of the boundary position in the y direction; S35, boundary condition update: according to the adjusted boundary position, the boundary conditions of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are recalculated and updated, which are expressed as: Q in (t)'=Q0+ΔQ(t,x b ',y b '); H out (t)'=H0+ΔH(t,x b ',y b '); u in (t)'=u0+Δu(t,x b ',y b '); v in (t)'=v0+Δv(t,x b ',y b '); h in (t)'=h0+Δh(t,x b ',y b '); Among them, Q in (t)' is the updated flow at the upstream boundary at time t, Q0 is the initial flow, ΔQ(t,x b ',y b ') is the position at time t and the new boundary position (x b ',y b ') flow change, H out (t)' is the updated water level at the downstream boundary at time t, H0 is the initial water level, ΔH(t,x b ',y b ') is the position at time t and the new boundary position (x b ',y b ') water level change, u in (t)' is the updated x-direction velocity of the upstream boundary at time t, u0 is the initial x-direction velocity, Δu(t,x b ',y b ') is the position at time t and the new boundary position (x b ',y b The velocity change in the x direction at ', v in (t)' is the updated y-direction velocity of the upstream boundary at time t, v0 is the initial y-direction velocity, Δv(t,x b ',y b ') is the position at time t and the new boundary position (x b ',y b ') in the y direction, h in (t)' is the updated water depth at the upstream boundary at time t, h0 is the initial water depth, Δh(t,x b ',y b ') is the position at time t and the new boundary position (x b ',y b ') water depth change; S4, Adaptive Grid Optimization: Dynamically adjust the scale and distribution density of grid cells according to the changes in flow velocity and water depth in the area, including: S41, flow velocity and water depth monitoring: real-time monitoring of flow velocity and water depth in the coupling area; S42, grid density adjustment: according to the monitored flow velocity and water depth, an adaptive grid optimization algorithm is used to dynamically adjust the scale and distribution density of the grid cells; S43, grid optimization: optimizing the adjusted grid cells; S5, calculation of coupling parameters: based on the adjusted boundary position and the scale and distribution density of the grid cells, within the coupling region, the boundary conditions of the two-dimensional hydrodynamic model are calculated according to the flow and water level data of the one-dimensional hydrodynamic model, and the boundary conditions of the one-dimensional hydrodynamic model are corrected according to the flow velocity and water depth data of the two-dimensional hydrodynamic model, and the coupling parameters are calculated repeatedly until the parameters of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model in the coupling region reach a balance; S6, synchronization of time steps: set the time steps of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model so that the time steps of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model are synchronized. In each time step, the one-dimensional hydrodynamic model is calculated first, then the two-dimensional hydrodynamic model is calculated, and finally the data is exchanged and corrected in the coupling area; S7, result output and analysis: output the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, including flow, water level, flow velocity and water depth, and analyze the calculation results to evaluate the accuracy and stability of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model.

2. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 1, characterized in that: The model preparation in S1 includes: S11, construct a one-dimensional hydrodynamic model: select the implicit difference method as the numerical calculation method, define the calculation area of ​​the one-dimensional hydrodynamic model, the calculation area is represented by the coordinate system as x∈[0,L], where L is the length of the river channel, set the boundary conditions of the one-dimensional hydrodynamic model, including the flow rate Q at the upstream boundary in and the water level H at the downstream boundary out , expressed as: Q in (t)=Q0+ΔQ(t); H out (t)=H0+ΔH(t); Among them, Q0 and H0 are the initial flow and water level, ΔQ(t) and ΔH(t) are the changes in time t; The one-dimensional hydrodynamic model is expressed as: The mass conservation equation: Momentum conservation equation: Among them, A is the cross-sectional area, Q is the flow rate, t is the time, x is the spatial coordinate, g is the gravitational acceleration, H is the water level, and K is the cross-sectional flow coefficient; S12, construct a two-dimensional hydrodynamic model: select the finite volume method as the numerical calculation method, define the calculation area of ​​the two-dimensional hydrodynamic model, and the calculation area is represented by the coordinate system x∈[0,L x ] and y∈[0,L y ], where L x and L y To calculate the length and width of the region, the boundary conditions of the two-dimensional hydrodynamic model are set, including the flow velocity and water depth at the region boundary, expressed as: u in (t)=u0+Δu(t); v in (t)=v0+Δv(t); h out (t)=h0+Δh(t); Among them, u in is the velocity component in the x direction, v in is the velocity component in the y direction, u0, v0 and h0 are the initial flow velocity and water depth, Δu(t), Δv(t) and Δh(t) are the changes in time t; The two-dimensional hydrodynamic model is expressed as: The mass conservation equation: Momentum conservation equation: In the x direction: In the y direction: Where h is the water depth, u is the velocity component in the x direction, v is the velocity component in the y direction, g is the gravitational acceleration, H is the water level, and f x and f y is the volume force in the x and y directions; S13, setting initial conditions: according to actual hydrodynamic observation data, including flow rate, flow velocity, water level and water depth, setting initial flow rate and initial water level for the one-dimensional hydrodynamic model, and setting initial flow velocity and initial water depth for the two-dimensional hydrodynamic model; S14, determine the coupling region: the coupling region is the overlapping region of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. The definition of the coupling region is expressed by a coordinate system as follows: x∈[L1,L2]; y∈[L3,L4]; Among them, L1, L2, L3 and L4 are the boundary coordinates of the coupling area.

3. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 2, characterized in that: The division of the coupling area in S2 includes: S21, coupled region meshing: The two-dimensional mesh cells are rectangular or polygonal mesh cells. The calculation of mesh cell area and volume includes: S211, Calculation of area and volume of rectangular grid cells: A rect =Δx·Δy; In rect =A rect ·h; Among them, A rect and V rect are the area and volume of the rectangular grid cell, respectively, Δx is the length of the rectangular grid cell in the x direction, Δy is the width of the rectangular grid cell in the y direction, and h is the water depth within the grid cell; S212, calculation of area and volume of polygonal mesh elements: In poly =A poly ·h; Among them, A poly and V poly are the area and volume of the polygonal mesh unit, (x k ,y k ) is the coordinate of the kth vertex of the polygonal mesh unit, and n is the number of vertices of the polygonal mesh unit; S22, grid cell calculation: The change of conserved quantity is represented by boundary flux, including: S221, flux F of the mass conservation equation: Among them, h is the water depth, hu is the product of water depth and velocity in the x direction, and hv is the product of water depth and velocity in the y direction; S222, Fluxes G and H of the momentum conservation equation: Where hu is the product of water depth and velocity in the x direction, is the change of momentum flux in the x direction, huv is the product of water depth and x-direction velocity and y-direction velocity, and hv is the product of water depth and y-direction velocity. is the change of momentum flux in the y direction; S223, discretized form: Among them, U i is the volume average of the conservative variable, ΔV i is the volume of the grid unit, F ij is the boundary flux, A ij is the boundary area, S i is the source term; S23, set exchange boundary: set exchange boundary in the coupling region to define the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as: Q exchange =Q 1D +α·(Q 2D -Q 1D ); Among them, Q exchange is the flow at the exchange boundary, Q 1D and Q 2D are the flow rates calculated by the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, respectively, and α is the adjustment coefficient; S24, definition of interaction region: determine the interaction region between the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model. The hydrodynamic observation data in the interaction region are weighted averaged according to the calculation results of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as: P interaction =β·P 1D +(1-β)·P 2D ; Among them, P interaction is the hydrodynamic observation data of the interaction area, P 1D and P 2D are the parameters calculated by the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model respectively, and β is the weight coefficient.

4. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 3, characterized in that: The flow rate and water depth monitoring in S41 includes: S411, data monitoring: arranging flow velocity sensors and water depth sensors in the coupling area to monitor the flow velocity and water depth in the coupling area in real time; S412, preliminary data processing: use a low-pass filter to remove noise and outliers from the monitored flow velocity and water depth.

5. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 4, characterized in that: The adaptive mesh optimization algorithm in S42 adopts a gradient-based adaptive mesh generation algorithm, and the gradient-based adaptive mesh generation algorithm includes: S421, calculate flow velocity and water depth gradient: calculate the spatial gradient of flow velocity and water depth, expressed as: Among them, G u is the flow velocity gradient, is the partial derivative of flow velocity in the x direction, is the partial derivative of the velocity in the y direction, G h is the water depth gradient, is the partial derivative of water depth in the x direction, is the partial derivative of water depth in the y direction; S422, introduce weighting factors: introduce weighting factors for flow velocity and water depth gradient, expressed as: W u =w1·G u +w2·G h ; <h2 style=";text-align:left;direction:ltr">W<h2 style=";text-align:left;direction:ltr"> h <h2 style=";text-align:left;direction:ltr"> =w3·G<h2 style=";text-align:left;direction:ltr"> h <h2 style=";text-align:left;direction:ltr"> +w4·G<h2 style=";text-align:left;direction:ltr"> u <h2 style=";text-align:left;direction:ltr"> ; Among them, w1, w2, w3 and w4 are weight factors; S423, dynamically adjust the grid density: dynamically adjust the scale and distribution density of the grid cells according to the calculated weighted gradient value, expressed as: For a refined mesh: For a coarse mesh: Δx new =Δx·min(1,W u / ∈ u ),Δy new =Δy·min(1,W h / ∈ h ); Where Δx new is the length of the adjusted grid unit in the x direction, Δx is the length of the original grid unit in the x direction, and W u is the weighted velocity gradient, ∈ u is the threshold of flow velocity gradient, Δy new is the length of the adjusted grid unit in the y direction, Δy is the length of the original grid unit in the y direction, W h is the weighted water depth gradient, ∈ h is the threshold of water depth gradient.

6. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 5, characterized in that: The grid optimization in S43 includes: S431, initial grid adjustment: After adjusting the grid density, make a preliminary adjustment to the grid cells, expressed as: Among them, x i ' is the adjusted position of the i-th node, x j is the position of the adjacent node, N is the number of adjacent nodes; S432, Mesh Quality Assessment: Evaluate the quality of each mesh cell, using mesh quality metrics to assess the shape and size of the mesh, expressed as: Among them, q i is the quality index of the i-th grid unit, c1 is a constant parameter, A i is the area of ​​the ith grid unit, l j is the length of the jth edge, and n is the number of edges of the grid unit; S433, Laplace smoothing algorithm: Use the Laplace smoothing algorithm to optimize the mesh nodes and adjust the node positions to improve the mesh quality, expressed as: Among them, x i " is the optimized position of the i-th node, x i is the current node position, x j is the position of the adjacent node, N is the number of adjacent nodes, and λ is the smoothing factor; S434, iterative optimization: The mesh optimization process is iterated multiple times, expressed as: in, is the position of the i-th node after the k-th iteration, is the position of the adjacent node after the kth iteration.

7. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 1, characterized in that: The calculation of the coupling parameters in S5 includes: S51, Calculation of boundary conditions from one-dimensional hydrodynamic model to two-dimensional hydrodynamic model: Based on the adjusted boundary position and the scale and distribution density of the grid cells, the boundary conditions of the two-dimensional hydrodynamic model are calculated according to the flow and water level of the one-dimensional hydrodynamic model, expressed as: H 2D =H 1D +ΔH; Among them, Q 2D and H 2D are the flow and water level boundary conditions of the two-dimensional hydrodynamic model, Q 1D and H 1D are the flow and water level of the one-dimensional hydrodynamic model, A 2D and A 1D are the cross-sectional areas of the two-dimensional hydrodynamic model and the one-dimensional hydrodynamic model, respectively, and ΔH is the adjusted water level difference; S52, 2D hydrodynamic model calculation: Using the calculated boundary conditions, calculate the flow velocity and water depth in the 2D hydrodynamic model, expressed as: Among them, u is the flow velocity, Q is the flow rate, and A is the cross-sectional area; Among them, h is the water depth, Q is the flow rate, u is the flow velocity, and B is the fluid width; S53, Boundary condition correction from two-dimensional hydrodynamic model to one-dimensional hydrodynamic model: According to the flow velocity and water depth of the two-dimensional hydrodynamic model, the boundary condition of the one-dimensional hydrodynamic model is corrected, which is expressed as: Q 1D '=Q 1D +ΔQ; Among them, Q 1D ' and H 1D ' are the flow and water level boundary conditions of the modified one-dimensional hydrodynamic model, ΔQ is the flow correction value; S54, repeated calculation of coupling parameters: the calculation of coupling parameters is repeated until the parameters of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model in the coupling region reach equilibrium, and the equilibrium condition is expressed as: |Q 1D '-Q 2D |<∈ Q ; |H 1D '-H 2D |<∈ H ; Among them, ∈ Q and ∈ H are the thresholds for flow and water level balance conditions, respectively.

8. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 1, characterized in that: The synchronization of the time steps in S6 includes: S61, setting of time step: setting the time step of the one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model so that the time steps of the two models are synchronized, which is expressed as: Δt 1D =Δt 2D =min(Δt CFL ,Δt S ); Among them, Δt 1D and Δt 2D are the time steps of the one-dimensional and two-dimensional hydrodynamic models, Δt CFL is the time step that satisfies the CFL condition, Δt S is the time step that satisfies the stability condition; S62, CFL condition: Calculate the time step that satisfies the CFL condition, expressed as: Where Δx is the grid unit length, u is the flow velocity, and c is the wave velocity; S63, Stability Condition: Calculate the time step that satisfies the stability condition, expressed as: Where Δx is the grid unit length, v is the kinematic viscosity coefficient; S64, time-stepping synchronous calculation: In each time step, the one-dimensional hydrodynamic model is calculated first, then the two-dimensional hydrodynamic model is calculated, and finally the data is exchanged and corrected in the coupling area, which is expressed as: Compute a one-dimensional hydrodynamic model: Among them, Q 1D is the flow rate of the one-dimensional hydrodynamic model, H 1D is the water level of the one-dimensional hydrodynamic model; Compute the 2D hydrodynamic model: Data exchange and correction: Q 1D =Q 2D ; H 1D =H 2D ; Among them, Q 1D is the flow rate of the one-dimensional hydrodynamic model, H 1D is the water level of the one-dimensional hydrodynamic model, h 2D is the water depth of the two-dimensional hydrodynamic model, u 2D is the velocity component of the two-dimensional hydrodynamic model in the x direction, v 2D is the velocity component of the two-dimensional hydrodynamic model in the y direction, H 2D is the water level of the two-dimensional hydrodynamic model, f x2D is the volume force in the x direction of the two-dimensional hydrodynamic model, f y2D is the volume force in the y direction of the two-dimensional hydrodynamic model, and g is the gravitational acceleration.

9. The coupling method for a one-dimensional hydrodynamic model and a two-dimensional hydrodynamic model according to claim 8, characterized in that: The result output and analysis in S7 include: S71, result output: output the calculation results of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, expressed as: Q out =Q 1D +Q 2D ; H out =H 1D +H 2D ; S72, calculation result analysis: based on the output flow, water level, flow velocity and water depth, generate a time series graph and a spatial distribution graph, expressed as: TimeSeries(Q out ,H out ,u out ,h out ); SpatialDistribution(Q out ,H out ,u out ,h out ); S73, accuracy assessment: The error analysis method is used to evaluate the calculation accuracy of the coupled one-dimensional hydrodynamic model and the two-dimensional hydrodynamic model, which is expressed as: ∈ Q =|Q observed -Q out |; ∈ H =|H observed -H out |; ∈ u =|in observed -in out |; ∈ h =|h observed -h out |; Among them, Q observed ,H observed ,u observed and h observed are the observed flow, water level, velocity and water depth, respectively; S74, Stability Assessment: The stability of the model is assessed by calculating the change in the results of the model at different time steps and different initial conditions, expressed as: Among them, S Q , S H , S u , S h They are the stability evaluation indicators of flow, water level, flow velocity and water depth. They are the rates of change of flow, water level, flow velocity and water depth with respect to time t respectively.

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