A method for simulating storage and release processes based on a zoned virtual reservoir

Abstract

The present application relates to the technical field of hydraulic engineering, and more particularly to a kind of storage and discharge process simulation method based on partition virtual reservoir.The method discretizes the study area into two-dimensional grid and divides sub-partition, establishes virtual reservoir for each sub-partition, and forms grid-sub-partition-reservoir mapping.Two-dimensional model calculates inflow according to grid storage and discharge capacity parameters and flows into corresponding reservoir;When the reservoir reaches maximum storage capacity, water inflow is triggered to be fused, and the water volume automatically recovers after falling.Water reservoir is connected to one-dimensional river channel through coupling component, and outflow and anti-backflow are controlled according to river water level;When water volume is insufficient, multiple components distribute outflow in proportion;Non-iterative volume constraint is used to realize mass conservation.The present application has low data requirement and high efficiency, and is suitable for urban waterlogging simulation, sponge city evaluation and planning comparison.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and in particular to a method for simulating the storage and discharge process based on a zoned virtual reservoir. Background Technology

[0002] With the increasing frequency of extreme rainfall events and the continuous intensification of watershed development activities, the demand for simulation of regional flooding, water transport, and surface runoff processes is growing. Current flood and hydrodynamic simulations typically employ two-dimensional surface models or a coupling of two-dimensional surface models with one-dimensional river channel models to simulate the confluence, transport, and discharge processes of rainfall runoff. However, existing technologies still have the following shortcomings: (i) The generalization of two-dimensional models leads to insufficient representation of the storage and excretion process. Two-dimensional surface models typically use finite-resolution computational grids to discretize actual terrain. To ensure computational efficiency, many small-scale but crucial water storage and drainage units cannot be explicitly represented or are simplified. These include underground drainage systems, small ditches, tributary channels, soil infiltration layers, sponge city structures, water storage depressions, and other units with functions of water storage, transport, infiltration, or discharge. These storage and drainage units can alter regional water distribution and transport paths; their absence can lead to discrepancies between simulation results and actual conditions.

[0003] (ii) Detailed modeling relies heavily on basic data. Describing these storage and drainage units using explicit modeling typically requires acquiring a large amount of basic data, including drainage facility parameters, ditch and river cross-sectional data, soil infiltration parameters, spatial distribution information of facilities, and their topological connections. However, in many regions, relevant data is missing, incomplete, or prohibitively expensive to obtain, making it difficult to establish refined models. In the absence of detailed data, how to reasonably estimate the combined effects of these storage and drainage units remains a crucial issue in practical applications.

[0004] (iii) High modeling cost and low application efficiency of detailed models Even with relatively complete data, explicit modeling of numerous detailed storage and drainage units still requires complex data processing, model building, parameter calibration, and computational analysis, resulting in high modeling costs. Furthermore, as model complexity increases, computational efficiency and stability may be affected. In many engineering applications, the research objective is often to assess the overall regional storage and drainage capacity and its impact on flood processes, rather than focusing on the detailed hydrodynamic processes within each storage and drainage unit. Therefore, using detailed models for calculations often leads to a mismatch between input and return.

[0005] Therefore, a low-cost, highly stable method is needed to reduce modeling complexity and data requirements while maintaining reasonable physical meaning, and to achieve efficient coupling simulation between two-dimensional surface systems and one-dimensional river systems, so as to improve the applicability and computational efficiency of simulating regional flood processes, water transport processes, and hydrological response processes. Summary of the Invention

[0006] This invention provides a method for simulating the storage and discharge process based on a partitioned virtual reservoir, comprising the following steps: S1. In a two-dimensional computational grid, configure storage and drainage capacity parameters for each grid cell; S2. Based on the topographic features, hydrological response features, drainage organization features and / or management zones within the study area, the grid is divided into multiple sub-zones. A virtual reservoir is established for each sub-zone, and a mapping relationship is established between grid cells, sub-zones and virtual reservoirs. S3. Calculate the inflow rate of storage and discharge based on the storage and discharge capacity parameters configured in the grid unit, and channel the inflow rate into the corresponding virtual reservoir; trigger the inflow circuit breaker or recovery mechanism based on the current water volume and maximum capacity of the virtual reservoir. S4. Establish at least one coupling component between each virtual reservoir and the one-dimensional river system. The coupling component includes outflow control elevation, maximum outflow rate and anti-backflow logic, and delivers water to the river in the form of lateral side-to-side inflow. S5. Execute outflow or discharge control based on the relationship between river water level and outflow control elevation; when the virtual reservoir connects multiple coupling components and the current water volume is insufficient to meet the theoretical outflow of all coupling components, scale and allocate according to the theoretical outflow ratio of each coupling component. S6. A non-iterative volume constraint method is used to complete the mass exchange between the virtual reservoir and the river system, thereby realizing the mass conservation between the two-dimensional surface system and the one-dimensional river system.

[0007] As a preferred embodiment of the above technical solution, the storage and drainage capacity parameters are used to characterize the confluence, regulation, transport, infiltration and / or discharge capacity of unmodeled storage and drainage units within the study area; the storage and drainage units include underground drainage facilities, ditches, tributary channels, soil infiltration layers, sponge facilities and / or storage spaces.

[0008] As a preferred embodiment of the above technical solution, when the temporary water volume of the virtual reservoir... Reaching maximum storage capacity When the water level in the virtual reservoir drops to a certain level, the inflow circuit is triggered, blocking the flow of water from the corresponding grid cell into the virtual reservoir. Unreceived water continues to participate in the 2D surface runoff calculation. When the inflow capacity is automatically restored, The value range is 0.9 to 0.98.

[0009] As a preferred embodiment of the above technical solution, each grid cell establishes a mapping relationship with the virtual reservoir through sub-partitions, and multiple grid cells share a virtual reservoir.

[0010] As a preferred embodiment of the above technical solution, each virtual reservoir is connected to a one-dimensional river system through one or more coupling components; the coupling components include outflow control elevation, maximum outflow rate, backflow prevention judgment logic, and river-related position, which are used to manage the quality exchange between the virtual reservoir and the river system.

[0011] As a preferred embodiment of the above technical solution, when the river water level is higher than the outflow control elevation, the corresponding coupling component stops the outflow to achieve backflow prevention control; when the river water level is lower than the outflow control elevation, the corresponding coupling component flows out at the maximum outflow rate.

[0012] As a preferred embodiment of the above technical solution, when the virtual reservoir is connected to multiple coupling components, the theoretical outflow of the virtual reservoir is the sum of the theoretical outflows of each coupling component; when the current water volume of the virtual reservoir is insufficient to meet the total theoretical outflow, the actual outflow of each coupling component is scaled and allocated according to the following formula: in, is the sub-partition number and the corresponding virtual reservoir number, and j is the coupling component number. For the first Actual output flow rate of each coupling component For the first The theoretical output flow rate of each coupling component. For virtual water storage The current temporary water storage volume, This represents the total number of coupling components; after scaling, the sum of the actual outflow of each coupling component does not exceed the current temporary water volume of the virtual reservoir.

[0013] As a preferred embodiment of the above technical solution, the virtual reservoir and the one-dimensional river system exchange mass using a non-iterative volume constraint method. The actual outflow volume is simultaneously deducted from the virtual reservoir and added to the corresponding river calculation unit in a lateral inflow manner, thereby achieving mass conservation between the two-dimensional system and the one-dimensional system.

[0014] As a preferred embodiment of the above technical solution, in step S3, the storage and discharge flow rate is calculated as follows: For each grid cell, the inflow / outflow rate Represented as: in, For the grid water depth, Storage and discharge capacity parameters; function Select the corresponding calculation model based on the type of storage and drainage unit: When the storage and drainage unit is a drainage structure, the orifice flow formula and / or weir flow formula are used for calculation; When the storage and discharge unit is a transfer facility, the open channel flow formula is used for calculation; When the storage and drainage unit is an infiltration unit, the infiltration model is used for calculation; When the storage and discharge unit is a regulation and storage facility, empirical formulas are used for calculation; The total inflow rate of the virtual reservoir corresponding to the sub-zone is obtained by summing the inflow and outflow rates of all grid cells within the same sub-zone: in, For the first Sub-partitions The flow rate entering the i-th reservoir is given by k, where k is the k-th cell of the two-dimensional grid.

[0015] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects: 1. Low data requirements: No complete pipeline network data is required, only topographic features, hydrological response features or management zoning information is needed, which is of practical value to areas with scarce data; 2. High modeling efficiency: The mapping mechanism enables multiple grids to share a reservoir, avoiding the cost of modeling each grid individually; 3. Good computational stability: Non-iterative volume constraints avoid the risk of nonlinear iteration divergence; 4. Complete functions: It realizes complete functions such as storage and discharge, regulation and storage, backflow prevention, and water volume distribution of multiple discharge outlets, meeting the needs of rapid engineering simulation; 5. Wide range of applications: It can cover various storage and drainage unit types such as underground drainage facilities, ditches, tributary rivers, soil infiltration layers, sponge facilities, and storage and regulation spaces.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall process of Example 1; Figure 2 A schematic diagram of the proportional outflow of multiple coupled components in a virtual water storage tank; Figure 3 A schematic diagram of inflow and fuse control for a virtual water storage tank; Figure 4 This is a schematic diagram of the mapping between a two-dimensional network and a virtual water storage tank. Figure 5 This is a schematic diagram of the storage and discharge model. Detailed Implementation

[0018] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] Example 1: See Figure 1 This invention provides a method for simulating the storage and discharge process based on a partitioned virtual reservoir, such as... Figure 1 As shown and Figure 5 As shown, the specific steps include: S1, Initialization parameters The study area is divided into two-dimensional grids G={ }, k=1,…,N; The grid is divided into multiple sub-regions based on the topographic features, hydrological response characteristics, drainage organization characteristics, and / or management zones within the study area. }, i=1,…,M; Create a virtual reservoir for each sub-partition ,like Figure 4 As shown, initialize the current water storage volume. and maximum storage capacity ; Configure corresponding coupling components for the water storage tank ={ j=1,…, },like Figure 2 As shown; Configure the outflow control elevation of the coupling component With maximum outflow rate .

[0020] S2, Calculation of storage and discharge inflow rates Time step Within each grid cell, the storage and drainage inflow can be uniformly expressed as: in: Let be the storage and discharge flow rate of the k-th unit; For grid water depth; These are parameters related to storage and drainage capacity.

[0021] function Automatically select the corresponding calculation model based on the type of storage and drainage unit: When the storage and drainage unit is an underground drainage facility, rainwater inlet, inspection well, or other drainage structure, the orifice flow formula, weir flow formula, or a combination thereof can be used for calculation. Taking the orifice flow formula as an example: in: denoted as ρ, where A is the flow coefficient; A is the orifice area; g is the acceleration due to gravity. This represents the water depth within the grid cell.

[0022] When the storage and discharge unit is a transport facility such as a ditch, open channel, or tributary river, the Manning formula, the simplified form of the Saint-Venant equation, or other open channel flow formulas can be used for calculation. Taking the Manning formula as an example: Where: n is the Manning roughness coefficient; A is the cross-sectional area of ​​the flow path; R is the hydraulic radius; and S is the gradient.

[0023] When the storage and drainage unit is an infiltration unit such as a soil infiltration layer, green space, or sponge city infrastructure, the Horton model, Green-Ampt model, Philip model, or empirical infiltration formulas can be used for calculation. Taking the Horton model as an example: Where: T is the duration calculated from the start of the infiltration process. The initial infiltration rate; To stabilize the infiltration rate; k is the attenuation coefficient; A is the infiltration area.

[0024] When the storage and discharge unit is a regulating space, underground water storage facility, or other storage and discharge facility, empirical formulas can be used for calculation, such as Bernoulli's equation, Manning's formula, and linear formulas. Taking the linear regulating model as an example: Where: K is the regulation and discharge coefficient; To activate the water depth threshold.

[0025] The inflow rate of each reservoir is obtained by summing the flow rates of all units within the zone: Update the temporary water level in the reservoir: t is the time step for hydrodynamic calculation.

[0026] S3, Fuse Control like Figure 3 As shown, when When the circuit breaker is triggered, the corresponding grid storage and discharge inflow is shut off, and the unreceived water continues to participate in the two-dimensional overflow.

[0027] when Time-lapse recovery, preferred =0.95.

[0028] S4. Calculation of outflow from the reservoir For each coupled component, obtain the water level of the corresponding river segment of the coupled object. Based on the river level and outflow control elevation, the following can be determined: when At that time, theoretical output flow rate for: when hour: in, The outflow control elevation is the one corresponding to the j-th coupling component connecting the i-th reservoir.

[0029] After calculating the theoretical outflow, the current water volume in the virtual reservoir satisfies: At that time, each coupling component executes outflow according to the theoretical outflow rate. At that time, the actual outflow rate of each coupling component is calculated by scaling proportionally: This is to ensure that the total outflow does not exceed the amount of water temporarily stored in the reservoir. The actual outflow rate is the value of the j-th coupling component connected to the i-th reservoir.

[0030] Update the current water level in the reservoir: S5. Calculation of one-dimensional hydrodynamic receiver side inflow The actual outflow rate of each coupling component The corresponding river channel computational unit is added via lateral inflow. The river hydrodynamic model updates the river level after receiving the lateral inflow, and the updated river level is used to determine the outflow in the next time step. This step achieves mass conservation between the two-dimensional surface system and the one-dimensional river channel system, and the entire calculation process only requires information from the current time step, without needing to solve a system of algebraic equations or achieve iterative convergence.

[0031] S6, Iterative Loop Proceed to the next time step Repeat steps S2 to S5 to achieve real-time dynamic simulation.

[0032] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for simulating the storage and discharge process based on a partitioned virtual reservoir, characterized in that, Includes the following steps: S1. In a two-dimensional computational grid, configure storage and drainage capacity parameters for each grid cell; S2. Based on the topographic features, hydrological response features, drainage organization features and / or management zones within the study area, the grid is divided into multiple sub-zones. A virtual reservoir is established for each sub-zone, and a mapping relationship is established between grid cells, sub-zones and virtual reservoirs. S3. Calculate the inflow rate of storage and discharge based on the storage and discharge capacity parameters configured in the grid unit, and channel the inflow rate into the corresponding virtual reservoir; trigger the inflow circuit breaker or recovery mechanism based on the current water volume and maximum capacity of the virtual reservoir. S4. Establish at least one coupling component between each virtual reservoir and the one-dimensional river system. The coupling component includes outflow control elevation, maximum outflow rate and anti-backflow logic, and delivers water to the river in the form of lateral side-to-side inflow. S5. Execute outflow or discharge control based on the relationship between river water level and outflow control elevation; when the virtual reservoir connects multiple coupling components and the current water volume is insufficient to meet the theoretical outflow of all coupling components, scale and allocate according to the theoretical outflow ratio of each coupling component. S6. A non-iterative volume constraint method is used to complete the mass exchange between the virtual reservoir and the river system, thereby realizing the mass conservation between the two-dimensional surface system and the one-dimensional river system. When the virtual reservoir temporarily stores water Reaching maximum storage capacity When the water level in the virtual reservoir drops to a certain level, the inflow circuit is triggered, blocking the flow of water from the corresponding grid cell into the virtual reservoir. Unreceived water continues to participate in the 2D surface runoff calculation. When the inflow capacity is automatically restored, The value range is 0.9 to 0.98; When a virtual reservoir is connected to multiple coupling components, the theoretical outflow of the virtual reservoir is the sum of the theoretical outflows of each coupling component. When the current water volume of the virtual reservoir is insufficient to meet the total theoretical outflow, the actual outflow of each coupling component is scaled and allocated according to the following formula: in, is the sub-partition number and the corresponding virtual reservoir number, and j is the coupling component number. For the first Actual output flow rate of each coupling component For the first The theoretical output flow rate of each coupling component. For virtual water storage The current temporary water storage volume, This represents the total number of coupling components; After scaling, the sum of the actual outflow of each coupling component does not exceed the current temporary water volume of the virtual reservoir.

2. The method for simulating the storage and discharge process based on a partitioned virtual reservoir according to claim 1, characterized in that: The storage and drainage capacity parameters are used to characterize the confluence, regulation, transport, infiltration and / or discharge capacity of unmodeled storage and drainage units within the study area; the storage and drainage units include underground drainage facilities, ditches, tributary channels, soil infiltration layers, sponge facilities and / or storage spaces.

3. The method for simulating the storage and discharge process based on a partitioned virtual reservoir according to claim 1, characterized in that: Each grid cell establishes a mapping relationship with the virtual reservoir through sub-partitions, and multiple grid cells share a single virtual reservoir.

4. The method for simulating the storage and discharge process based on a partitioned virtual reservoir according to claim 1, characterized in that: Each virtual reservoir is connected to a one-dimensional river system via one or more coupling components; the coupling components include outflow control elevation, maximum outflow rate, backflow prevention judgment logic, and river association position, which are used to manage the quality exchange between the virtual reservoir and the river system.

5. The method for simulating the storage and discharge process based on a partitioned virtual reservoir according to claim 4, characterized in that: When the river level is higher than the outflow control elevation, the corresponding coupling component stops the outflow to prevent backflow; when the river level is lower than the outflow control elevation, the corresponding coupling component flows out at the maximum outflow rate.

6. The method for simulating storage and discharge processes based on a partitioned virtual reservoir according to any one of claims 1 to 5, characterized in that: Mass exchange is performed between the virtual reservoir and the one-dimensional river system using a non-iterative volume constraint method. The actual outflow volume is simultaneously deducted from the virtual reservoir and added to the corresponding river calculation unit in a lateral inflow manner, thereby achieving mass conservation between the two-dimensional system and the one-dimensional system.

7. The method for simulating the storage and discharge process based on a partitioned virtual reservoir according to claim 1, characterized in that: In step S3, the storage and discharge flow rate is calculated as follows: For each grid cell, the inflow / outflow rate Represented as: in, For the grid water depth, Storage and discharge capacity parameters; function Select the corresponding calculation model based on the type of storage and drainage unit: When the storage and drainage unit is a drainage structure, the orifice flow formula and / or weir flow formula are used for calculation; When the storage and discharge unit is a transfer facility, the open channel flow formula is used for calculation; When the storage and drainage unit is an infiltration unit, the infiltration model is used for calculation; When the storage and discharge unit is a regulation and storage facility, empirical formulas are used for calculation; The total inflow rate of the virtual reservoir corresponding to the sub-zone is obtained by summing the inflow and outflow rates of all grid cells within the same sub-zone: in, For the first Sub-partitions Let k be the inflow rate into the i-th reservoir, and k be the k-th cell of the two-dimensional grid.

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