A multi-layer global grid generation method for the entire process of irrigation area hydrodynamics

Abstract

The present invention discloses a multi-layer global grid partitioning method for the entire process of irrigation area hydrodynamics, which belongs to the technical field of irrigation area water movement analysis, including: designing a four-layer grid structure, and defining corresponding control equations for each layer of the four-layer grid structure to obtain a four-layer irrigation area hydrodynamic process layer; defining water flow fluxes between different irrigation area hydrodynamic process layers according to the four-layer irrigation area hydrodynamic process layer to obtain a multi-layer global grid for the entire process of irrigation area hydrodynamics. By defining a four-layer grid structure and water flow fluxes between different grid layers, the present invention realizes the overall spatial discretization and seamless watertight splicing of the entire process of irrigation area hydrodynamics, thereby improving the accuracy and efficiency of irrigation area hydrodynamic simulation; by defining water flow fluxes between different grid structure layers, the continuity and integrity of the hydrodynamic process are ensured; at the same time, the present invention supports real-time rendering and user interaction, improves user experience, and can meet the needs of digital twin irrigation area construction.

Description

Technical Field

[0001] The invention belongs to the technical field of water movement analysis in irrigation areas, and in particular relates to a multi-layer global grid partitioning method for the entire process of water dynamics in an irrigation area. Background Art

[0002] The water movement process in the irrigation area includes the entire process of canal water (surface water network), farmland surface water, soil and groundwater. To build a digital twin irrigation area, it is necessary to establish a digital mapping of these physical processes, that is, to establish a digital irrigation area that corresponds one-to-one with the real physical irrigation area. The digital irrigation area can not only carry out real-time interactive simulation of the entire hydrodynamic process, but also render and present the simulated water process to the user in real time. This requires the global spatial grid discretization of the overall calculation area involved in the entire hydrodynamic process of the irrigation area, so that all areas of the irrigation area form a rotatable and scalable 3D whole, and then build a real-time online 3D digital twin irrigation area that can be calculated, simulated, rendered, and interactively simulated.

[0003] The existing spatial grid partitioning methods are difficult to discretize the canal network, farmland surface, soil and underground areas as a whole, and it is even more difficult to seamlessly and watertightly splice each area, resulting in the inability to perform real-time overall rendering and presentation, the inability to integrate simulation calculation and rendering, and the inability to meet the needs of digital twin irrigation district construction. To this end, this patent proposes a multi-layer 3D adaptive quadrilateral spatial grid partitioning method, which can partition the spatial domain involved in the entire process of irrigation district hydrodynamics as a whole, and can seamlessly and watertightly splice all areas, providing technical support for the construction of a digital twin irrigation district at an overall scale. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a multi-layer global grid division method for the entire process of irrigation district hydrodynamics, which can divide the spatial domain involved in the entire process of irrigation district hydrodynamics as a whole, and seamlessly and watertightly splice all areas, providing technical support for constructing a digital twin irrigation district of the overall scale.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a multi-layer global grid generation method for the whole process of irrigation area hydrodynamics, comprising the following steps:

[0006] S1: Design a four-layer grid structure;

[0007] S2: define the corresponding control equations for each layer of the four-layer grid structure to obtain four layers of irrigation area hydrodynamic process;

[0008] S3: Based on the four-layer irrigation area hydrodynamic process layer, the water flux is defined between different irrigation area hydrodynamic process layers, and a multi-layer global grid of the entire irrigation area hydrodynamic process is obtained.

[0009] The beneficial effects of the present invention are as follows: by defining a four-layer grid structure and water flow rates between different grid layers, the present invention realizes the overall spatial discretization and seamless watertight splicing of the entire irrigation area hydrodynamic process, thereby improving the accuracy and efficiency of the irrigation area hydrodynamic simulation; by defining the water flow rates between different grid structure layers, the continuity and integrity of the hydrodynamic process are ensured; at the same time, the present invention supports real-time rendering and user interaction, improves the user experience, and can meet the needs of the construction of digital twin irrigation areas.

[0010] Further: S2 defines corresponding control equations for each layer of the four-layer grid structure, and the specific operations are:

[0011] The Saint-Venant equations are defined on the first grid structure, which is used to distinguish the canal network and field distribution at the overall scale of the irrigation area;

[0012] A group of surface shallow water equations is defined on the second grid structure, wherein the second grid structure is used to distinguish horizontal hydrodynamic processes of shallow groundwater;

[0013] The Richards equation is defined on a third grid structure, wherein the third grid structure is used to distinguish vertical hydrodynamic processes between soil and groundwater;

[0014] The Boussinesq equation is defined on the fourth grid structure, which is used to distinguish the surface water network and the fine hydrodynamic process under the constraints of the surface micro-topography distribution inside the field.

[0015] The beneficial effect of the above further scheme is that by defining equations for the four-layer grid structure layer of the entire irrigation area hydrodynamic process, the continuity and integrity of the hydrodynamic process are ensured, while at the same time, the calculation efficiency is improved and the interpretability of the grid structure layer is enhanced.

[0016] Further: the water flux is defined between different grid structures in S3, including:

[0017] defining a water flux between the first grid structure and the fourth grid structure;

[0018] defining a water flux between the first grid structure and the third grid structure;

[0019] defining a water flux between the third grid structure and the fourth grid structure;

[0020] Define the water flux inside the first grid structure.

[0021] The beneficial effects of the above further scheme are: by defining the water flux between different grid structures, the hydraulic connection and data consistency between surface water, soil water and groundwater are achieved, which provides a guarantee for the accurate simulation of hydrodynamic processes, realizes the watertight seamless connection of hydrodynamic processes, and improves the accuracy and reliability of the simulation.

[0022] Furthermore, the water flux is defined between the first grid structure and the fourth grid structure, and the specific implementation method is as follows:

[0023] A1: The water volume in each field in the first grid structure is averaged over all grid points in the field to obtain the average water volume area of ​​each field;

[0024] A2: Assign the average water volume and area value of each field to the centroid point of the field to obtain the single grid water depth value of the field, and complete the definition of the water flow between the first grid structure and the fourth grid structure.

[0025] The beneficial effects of the above further scheme are: by defining the water flow rate between the first-layer grid structure and the fourth-layer grid structure, the precise connection between the canal network and the field hydrodynamic process in the irrigation area hydrodynamic model is achieved, the simulation accuracy is improved, and the model's ability to predict actual water flow behavior is enhanced.

[0026] Furthermore, the water flux is defined between the first grid structure and the third grid structure, and the specific implementation method is as follows:

[0027] B1: The surface water depth of each field in the first grid structure is used as the upper boundary water potential value of soil water movement in each field;

[0028] B2: According to the upper boundary water potential value of soil water movement in each field, the upper boundary water flux of soil water movement in each field is calculated by Darcy's law to complete the definition of water flux between the first grid structure and the third grid structure.

[0029] The beneficial effect of the above further scheme is that by defining the water flow rate between the first grid structure and the third grid structure, a seamless connection of the hydrodynamic process between surface water and soil water is achieved, thereby improving the simulation accuracy of the hydrological cycle.

[0030] Furthermore, the water flux is defined between the third grid structure and the fourth grid structure, and the specific implementation method is as follows:

[0031] C1: Obtain the water potential value of the positive and negative water potential change point near the bottom of the soil vertical area in the third grid structure;

[0032] C2: Use the water potential value in C1 as the groundwater depth value of the corresponding discrete point on the underground horizontal surface to complete the definition of the water flow between the third-layer grid structure and the fourth-layer grid structure.

[0033] The beneficial effects of the above further scheme are: by defining the water flow rate between the third-layer grid structure and the fourth-layer grid structure, seamless connection of the hydrodynamic process between soil water and groundwater is achieved, the dynamic balance and continuity between soil water and groundwater are ensured, and the simulation accuracy of comprehensive water resources management is improved.

[0034] Furthermore, the water flux is defined inside the first layer of the grid structure, and the specific implementation method is as follows:

[0035] D1: Get the water depth and ridge height of each field in the first grid structure;

[0036] D2: Determine whether the ridge between two adjacent fields in the first grid structure is less than one of the water depth values ​​of the two fields. If so, there is water flow between the two adjacent fields and enter D3. Otherwise, there is no water flow between the two adjacent fields.

[0037] D3: According to the water depth of each field and the height of the field ridge, the surface shallow water equation group is calculated to obtain the water flow between two adjacent fields in the first grid structure, completing the definition of the water flow inside the first grid structure.

[0038] The beneficial effect of the above further scheme is that by defining the water flow between fields separated by ridges, the lateral interaction of water flow between fields can be accurately simulated, ensuring that the water flow transfer caused by terrain differences or water level changes between fields is truly reflected. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of a multi-layer global grid generation method for the entire process of irrigation area hydrodynamics;

[0040] Figure 2 This is the first-layer grid structure diagram;

[0041] Figure 3 This is the second-layer grid structure diagram;

[0042] Figure 4 This is the third-layer grid structure diagram;

[0043] Figure 5 This is the fourth-layer grid structure diagram. DETAILED DESCRIPTION

[0044] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0045] like Figure 1 As shown, a multi-layer global grid generation method for the entire irrigation area hydrodynamic process includes the following steps:

[0046] S1: Design a four-layer grid structure;

[0047] S2: define the corresponding control equations for each layer of the four-layer grid structure to obtain four layers of irrigation area hydrodynamic process;

[0048] S3: Based on the four-layer irrigation area hydrodynamic process layer, the water flux is defined between different irrigation area hydrodynamic process layers to obtain a multi-layer global grid of the entire irrigation area hydrodynamic process.

[0049] In one embodiment of the present invention, the Saint-Venant equations are defined on the first grid structure, and the first grid structure is used to distinguish the canal network and field distribution of the overall scale of the irrigation area, such as Figure 2 As shown in the figure, it is the first-layer grid structure diagram, which can describe the surface water network. The expression of the Saint-Venant equation group is as follows:

[0050]

[0051] Among them, A is the cross-sectional area of ​​water flow in the surface water network, t is time, Q is the water flow rate, x is the flow direction of water flow, u is the average water flow velocity in the flow cross section, ζ is the water level in the surface water network, which is the sum of the water depth and the relative bottom elevation of the water network, n is the manning roughness coefficient, R is the hydraulic radius, and g is the acceleration of gravity.

[0052] The surface shallow water equations are defined on the second grid structure. The second grid structure is used to distinguish the horizontal hydrodynamic process of shallow groundwater, such as Figure 3 As shown in the figure, it is the second-layer grid structure diagram, which can describe the surface water of farmland. The expression of the surface shallow water equation group is as follows:

[0053]

[0054] Where h is the surface water depth, t is time, x and y are two mutually perpendicular two-dimensional surface coordinate directions, u and v are the flow velocities along the x and y coordinate directions respectively, ζ is the surface water level, which is the sum of the surface water depth and the relative surface elevation, and g is the acceleration due to gravity.

[0055] The Richards equation is defined on the third grid structure, which is used to distinguish the vertical dynamic processes of soil and groundwater, such as Figure 4 As shown in the figure, it is the third-layer grid structure diagram, which can describe soil water, where the expression of Richards equation is as follows:

[0056]

[0057] Where θ is the soil water content, t is the time, D(θ) is the diffusivity, K(θ) is the hydraulic conductivity, and z is the vertical coordinate.

[0058] The Boussinesq equation is defined on the fourth grid structure, which is used to distinguish the fine hydrodynamic process under the constraints of surface water network and surface micro-topography distribution inside the field, such as Figure 5 As shown, this is the fourth-layer grid structure diagram, which can describe shallow groundwater. Figure 5 The legend is in the lower left corner, including: channel discrete points, farmland discrete points, channel distribution lines, farmland discrete lines, field boundary lines, field-ridge-field connection lines, and gates. The expression of the Boussinesq equation is as follows:

[0059]

[0060] Among them, S is the water supply degree, h is the shallow surface water depth, x and y are two mutually perpendicular two-dimensional surface coordinate directions, K xx is the shallow surface water permeability coefficient along the x-coordinate direction, K yy is the permeability coefficient of shallow surface water along the y-coordinate direction.

[0061] In one embodiment of the present invention, defining water flux between different grid structures in S3 includes:

[0062] The water flux is defined between the first grid structure and the fourth grid structure, and the specific implementation method is as follows:

[0063] A1: The water volume in each field in the first grid structure is averaged over all grid points in the field to obtain the average water volume area of ​​each field;

[0064] A2: Assign the average water volume and area value of each field to the centroid point of the field to obtain the single grid water depth value of the field, complete the definition of water flux between the fine water depth distribution of the internal grid of the field and the water depth distribution of the field as a single grid, and complete the definition of water flux between the first grid structure and the fourth grid structure.

[0065] The water flux is defined between the first and third grid structures, and the specific implementation is as follows:

[0066] B1: The surface water depth of each field in the first grid structure is used as the upper boundary water potential value of soil water movement in each field;

[0067] B2: Based on the upper boundary water potential value of soil water movement in each field, the upper boundary water flux of soil water movement in each field is calculated by Darcy's law, so as to achieve a watertight and seamless connection between the surface and soil hydrodynamic processes, and complete the definition of the water flux between the first grid structure and the third grid structure.

[0068] The water flux is defined between the third and fourth grid structures, and the specific implementation method is as follows:

[0069] C1: Obtain the water potential value of the positive and negative water potential change point near the bottom of the soil vertical area in the third grid structure;

[0070] C2: The water potential value in C1 is used as the groundwater depth value of the corresponding discrete point on the underground horizontal plane, that is, the water flux between soil water and groundwater is obtained, completing the definition of the water flux between the third-layer grid structure and the fourth-layer grid structure.

[0071] The water flux is defined inside the first layer of the grid structure. The specific implementation is as follows:

[0072] D1: Get the water depth and ridge height of each field in the first grid structure;

[0073] D2: Determine whether the ridge between two adjacent fields in the first grid structure is less than one of the water depth values ​​of the two fields. If so, there is water flow between the two adjacent fields and enter D3. Otherwise, there is no water flow between the two adjacent fields.

[0074] D3: According to the water depth of each field and the height of the field ridge, the surface shallow water equation group is calculated to obtain the water flow between two adjacent fields in the first grid structure, completing the definition of the water flow inside the first grid structure.

[0075] The beneficial effects of the present invention are as follows: by defining a four-layer grid structure and water flow rates between different grid layers, the present invention realizes the overall spatial discretization and seamless watertight splicing of the entire irrigation area hydrodynamic process, thereby improving the accuracy and efficiency of the irrigation area hydrodynamic simulation; by defining the water flow rates between different grid structure layers, the continuity and integrity of the hydrodynamic process are ensured; at the same time, the present invention supports real-time rendering and user interaction, improves the user experience, and can meet the needs of the construction of digital twin irrigation areas.

Claims

1. A multi-layer global grid generation method for the entire process of irrigation area hydrodynamics, characterized in that: The following steps are involved: S1: Design a four-layer grid structure; S2: define the corresponding control equations for each layer of the four-layer grid structure to obtain the four-layer irrigation area hydrodynamic process layer; In S2, corresponding control equations are defined for each layer of the four-layer grid structure, and the specific operations are: The Saint-Venant equations are defined on the first grid structure, which is used to distinguish the canal network and field distribution at the overall scale of the irrigation area; A group of surface shallow water equations is defined on the second grid structure, wherein the second grid structure is used to distinguish horizontal hydrodynamic processes of shallow groundwater; The Richards equation is defined on the third grid structure, wherein the third grid structure is used to distinguish the vertical hydrodynamic process of soil and groundwater; The Boussinesq equation is defined on the fourth grid structure, and the fourth grid structure is used to distinguish the surface water network and the fine hydrodynamic process under the constraints of the surface micro-topography distribution inside the field; S3: Based on the four-layer irrigation area hydrodynamic process layer, the water flux is defined between different irrigation area hydrodynamic process layers to obtain a multi-layer global grid of the entire irrigation area hydrodynamic process.

2. The multi-layer global grid generation method for the entire process of irrigation area hydrodynamics according to claim 1 is characterized in that: The water flux is defined between different grid structures in S3, including: defining a water flux between the first grid structure and the fourth grid structure; defining a water flux between the first grid structure and the third grid structure; defining a water flux between the third grid structure and the fourth grid structure; Define the water flux inside the first grid structure.

3. The multi-layer global grid generation method for the entire process of irrigation area hydrodynamics according to claim 2 is characterized in that: The water flux is defined between the first grid structure and the fourth grid structure, and the specific implementation method is as follows: A1: The water volume in each field in the first grid structure is averaged over all grid points in the field to obtain the average water volume area of ​​each field; A2: Assign the average water volume and area value of each field to the centroid point of the field to obtain the single grid water depth value of the field, and complete the definition of the water flow between the first grid structure and the fourth grid structure.

4. The multi-layer global grid generation method for the entire process of irrigation area hydrodynamics according to claim 2 is characterized in that: The water flux is defined between the first grid structure and the third grid structure, and the specific implementation method is as follows: B1: The surface water depth of each field in the first grid structure is used as the upper boundary water potential value of soil water movement in each field; B2: According to the upper boundary water potential value of soil water movement in each field, the upper boundary water flux of soil water movement in each field is calculated by Darcy's law to complete the definition of water flux between the first grid structure and the third grid structure.

5. The multi-layer global grid generation method for the entire process of irrigation area hydrodynamics according to claim 2 is characterized in that: The water flux is defined between the third grid structure and the fourth grid structure, and the specific implementation method is as follows: C1: Obtain the water potential value of the positive and negative water potential change point near the bottom of the soil vertical area in the third grid structure; C2: Use the water potential value in C1 as the groundwater depth value of the corresponding discrete point on the underground horizontal surface to complete the definition of the water flow between the third-layer grid structure and the fourth-layer grid structure.

6. The multi-layer global grid generation method for the entire process of irrigation area hydrodynamics according to claim 2 is characterized in that: The water flux is defined inside the first layer of grid structure, and the specific implementation method is as follows: D1: Get the water depth and ridge height of each field in the first grid structure; D2: Determine whether the ridge between two adjacent fields in the first grid structure is less than one of the water depth values ​​of the two fields. If so, there is water flow between the two adjacent fields and enter D3. Otherwise, there is no water flow between the two adjacent fields. D3: According to the water depth of each field and the height of the field ridge, the surface shallow water equation group is calculated to obtain the water flow between two adjacent fields in the first grid structure, completing the definition of the water flow inside the first grid structure.

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