A calculation method for converting into a double-layer equivalent river channel based on a Muskingum method parameter

Abstract

The application discloses a kind of based on Muskingum method parameter conversion to double-layer equivalent riverway's calculation method, including steps (1) the actual riverway with nonlinear characteristic is decomposed into two single-layer equivalent riverway;(2) according to single-layer equivalent riverway calculation formula and the first layer equivalent riverway parameter, the water depth, river width and riverway gradient of the first layer equivalent riverway are calculated;(3) by the function formula F of the cross section shape of second layer equivalent riverway about water depth and shape parameter is combined with the relationship formula of double-layer equivalent riverway water depth and cross section shape function F, the shape parameter value, maximum water depth and river width of double-layer equivalent riverway are solved.Compared with the existing single-layer equivalent riverway calculation method based on Muskingum parameter, the double-layer equivalent riverway calculation method is proposed, which can reflect the nonlinear characteristics of the actual riverway cross section shape.The application further realizes the expansion of large cross section elements in riverway, and improves the traditional hydrology riverway concentration calculation mode.

Description

Technical Field

[0001] This invention relates to a method for calculating the confluence of hydrological channels, and more particularly to a method for calculating channels based on the conversion of Muskingan method parameters into a two-layer equivalent channel. Background Technology

[0002] The Muskingan method, first proposed by McCarthy in 1938, is primarily used in river confluence calculations. Its main parameters are K and X. Based on these two parameters, the downstream outflow process can be calculated reliably by inputting the upstream inflow, yielding results with a certain degree of accuracy, making it suitable for research and engineering problems. However, the traditional Muskingan method is a black-box model; the internal state of the river channel during confluence is unclear, and information such as flow velocity and water level cannot be obtained.

[0003] A previously disclosed calculation method for converting Muskinggan parameters into equivalent channels (patent application number 202210745922X) utilizes two Muskinggan parameters combined with readily available channel parameters such as channel length L, roughness n, mean velocity-to-wave velocity coefficient α′, and peak flow Q to derive a calculation method for a single-layer equivalent channel based on Muskinggan parameters. However, this method idealizes the channel as a single function, which does not reflect the nonlinear characteristics of actual channels and fails to capture their complex, multi-layered nonlinear features. For example, in calculations of actual channels, it was found that the equivalent channel parameters calculated using the aforementioned single-layer equivalent channel method exhibit occasional deviations when compared with actual measurement results in subsequent channel cross-sectional flow prediction. To overcome these deviations, the calculation method for the single-layer equivalent channel needs improvement. Summary of the Invention

[0004] Purpose of the invention: To address the above problems, this invention proposes a calculation method based on the conversion of Muskinggan method parameters into a two-layer equivalent channel, which expands the hydraulic elements of the equivalent channel, reflects the nonlinear characteristics of complex channels, and improves the accuracy of subsequent channel hydrological data prediction.

[0005] Technical Solution: The technical solution adopted in this invention is a calculation method based on the conversion of Muskingan method parameters into a two-layer equivalent channel, including the following steps:

[0006] (1) The actual river with nonlinear characteristics is decomposed into two single-layer equivalent rivers. The lower layer of the two single-layer equivalent rivers is the first layer of equivalent rivers, and the higher layer of the two single-layer equivalent rivers is the second layer of equivalent rivers. The width of the first layer of equivalent rivers is equal to the width of the bottom of the second layer of equivalent rivers. The gradient of the two single-layer equivalent rivers is set to be equal.

[0007] (2) Based on the formula for calculating the single-layer equivalent channel and the parameters of the first-layer equivalent channel, the maximum water depth H1, the width B1 and the channel gradient i0 of the first-layer equivalent channel are calculated.

[0008] (3) Based on the maximum water depth, river width and river gradient of the first equivalent channel, set the cross-sectional shape of the second equivalent channel as a function F with respect to water depth and shape parameters. Combine the relationship between water depth and cross-sectional shape function F of the two equivalent channels to solve for the shape parameter value, maximum water depth H and river width B of the two equivalent channels.

[0009] The formula for calculating the single-layer equivalent river channel mentioned in step (2) is as follows:

[0010]

[0011] In the formula, R is the hydraulic radius, which has a functional relationship with the river width B1: R = g(B1), i0 is the channel gradient, n is the roughness coefficient, L is the channel length, α is the average velocity-to-wave velocity coefficient, K1 and X1 are the Muskingan method parameters of the first-layer equivalent channel, Q1 is the peak flow of the first-layer equivalent channel, F1(H1) is the cross-sectional area of ​​the first-layer equivalent channel, H1 is the maximum water depth of the first-layer equivalent channel cross-section, F1′(·) is the partial derivative of the cross-sectional area function F1(·) with respect to the water depth, and R′ is the partial derivative of the hydraulic radius function R with respect to the water depth.

[0012] The relationship between the double-layer equivalent channel depth and the cross-sectional shape function F mentioned in step (3) is as follows:

[0013]

[0014] in:

[0015] In the formula, R is the hydraulic radius function, i0 is the channel gradient, n is the roughness coefficient, L is the length of the segment, α is the average velocity-to-wave velocity coefficient, K2 and X2 are the parameters of the segment in the Muskingan method of the double-layer equivalent channel, Q2 is the peak flow of the double-layer equivalent channel, F(H) is the cross-sectional area function, H is the maximum water depth of the double-layer equivalent channel cross-section, B is the width of the double-layer equivalent channel, F′(H) is the partial derivative of the cross-sectional area function F(H) with respect to the water depth, and R′ is the partial derivative of the hydraulic radius function R with respect to the water depth.

[0016] In step (3), the function F for setting the cross-sectional shape of the second-level equivalent channel with respect to water depth and shape parameters is: When the second-level channel curve is exponential, the function F is: B = bH2 a +B1, When the second-level river channel curve is parabolic, the function F is: When the second-level channel curve is trapezoidal, the function F is: B = bH2 + a + B1, where H2 is the maximum water depth of the second-level equivalent channel cross section, B1 is the width of the first-level equivalent channel, a and b are the shape parameters of the two-level equivalent channels, and B is the width of the two-level equivalent channels.

[0017] When the second-level channel curve is exponential, based on the function F of the cross-sectional shape of the second-level equivalent channel with respect to water depth and shape parameters, and the relationship between the water depth and cross-sectional shape function F of the two-level equivalent channels, the calculation formulas for the shape parameters a, b, maximum water depth H, and channel width B of the two-level equivalent channels are derived:

[0018]

[0019] In the formula, i0 is the channel gradient, n is the roughness coefficient, L is the length of the segment, α is the average velocity-to-wave velocity coefficient, K2 and X2 are the parameters of the segment in the Muskingan method for the two-layer equivalent channel, Q2 is the peak flow rate of the two-layer equivalent channel, H is the maximum water depth of the two-layer equivalent channel, B is the width of the two-layer equivalent channel, H2 is the maximum water depth of the second-layer equivalent channel, B1 is the width of the first-layer equivalent channel, A1 is the cross-sectional area of ​​the first-layer equivalent channel, and a and b are the shape parameters of the two-layer equivalent channel.

[0020] During calculation, it is preferred to set the cross-sectional shape of the first layer of equivalent river channels to parabolic by default, and the cross-sectional shape of the second layer of equivalent river channels to exponential by default.

[0021] This invention proposes a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the calculation method based on Muskingan method parameters to convert into a two-layer equivalent channel.

[0022] The present invention also proposes a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the aforementioned calculation method for converting Muskinggan parameters into a two-layer equivalent channel.

[0023] Beneficial Effects: Compared with existing technologies, this invention has the following advantages: This invention decomposes the river channel into a two-layer equivalent channel. By establishing a two-layer equivalent channel calculation method, it can reflect the nonlinear characteristics of the actual river channel cross-sectional shape and the nonlinearity of complex river hydraulic elements. This invention further expands the large-section elements within the river channel, improves the traditional hydrological river confluence calculation model, facilitates the conversion to a hydrodynamic model for calculation, realizes the simulation of flow velocity and flow field processes, and further improves the accuracy of simulation results. It provides a new method for converting the traditional Muskingan method into a hydrodynamic model calculation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a double-layered equivalent river channel;

[0025] Figure 2 This is a schematic diagram of an equivalent river channel with an exponential structure at the second level;

[0026] Figure 3 This is a schematic diagram of a two-layer equivalent river channel generated by Muskingen data conversion of a section of the Yellow River. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] The calculation method based on Muskingan method parameters converted into a two-layer equivalent channel, as described in this invention, includes the following steps:

[0029] (1) Divide the river channel into two equivalent layers. For example... Figure 1 As shown, a real river channel with nonlinear characteristics is decomposed into two single-layer equivalent channels, each with different Muskingan parameters. When calculating cross-sectional information at different levels, the peak discharge Q and Muskingan parameters K and X need to be calculated using the parameters of the corresponding level, while the other parameter values ​​remain the same. Specifically, the Muskingan parameters for the lower-level first-layer equivalent channel are K1, X1, and peak discharge Q1; the Muskingan parameters for the two-layer equivalent channel are K2, X2, and peak discharge Q2. The width B1 of the first-layer equivalent channel is equal to the bottom width of the second-layer equivalent channel. The depth of the first-layer equivalent channel is H1, and the depth of the second-layer equivalent channel is H2. The channel gradients of the first and second-layer equivalent channels are defined as equal, i.e., i1 = i2 = i0.

[0030] (2) Based on the calculation formula of the single-layer equivalent channel and the parameters of the first-layer equivalent channel (including the preset cross-sectional area function of the first-layer channel), the maximum water depth H1, the width B1 and the channel gradient i0 of the first-layer equivalent channel are calculated. Then the channel gradient of the double-layer equivalent channel is also i0.

[0031] The first layer of equivalent channel parameters includes the first layer Muskingen parameters, hydraulic radius, peak flow, channel length, roughness, average velocity-to-wave velocity coefficient, and the first layer of equivalent channel cross-sectional area function F1(H1).

[0032] The formula for calculating the first-level equivalent river channel is:

[0033]

[0034] In the formula, R is the hydraulic radius function, and the hydraulic radius R has a functional relationship with the river width B1: R = g(B1). i0 is the channel gradient, n is the roughness coefficient, L is the channel length, α is the average velocity-to-wave velocity coefficient, K1 and X1 are the Muskingan method parameters of the first-layer equivalent channel, Q1 is the peak flow of the first-layer equivalent channel, F1(H1) is the cross-sectional area function of the first-layer equivalent channel, H1 is the maximum water depth of the first-layer equivalent channel cross-section, F1′(H1) is the partial derivative of the cross-sectional area function F1(H1) with respect to the water depth, and R′ is the partial derivative of the hydraulic radius function R with respect to the water depth.

[0035] (3) Based on the function F of the cross-sectional shape of the second-layer equivalent channel with respect to the water depth and shape parameters, and the relationship between the water depth and cross-sectional shape function F of the double-layer equivalent channel, solve for the shape parameter value, water depth and width B of the second-layer equivalent channel.

[0036] First, based on the formula for calculating a single-layer equivalent channel, it is necessary to derive the relationship between the maximum water depth H and the cross-sectional area F(H) of a double-layer equivalent channel. The cross-sectional area F(H) includes two shape parameters, and three related equations need to be established to solve for the second layer of the equivalent channel.

[0037] Formula for calculating a double-layer equivalent river channel:

[0038]

[0039] Substituting equation (1) into equation (2), we can eliminate... have to:

[0040]

[0041] Let the hydraulic radius R be:

[0042]

[0043] Then B = F′(H), substituting into equation (3) yields:

[0044]

[0045] By transforming equation (1), we can obtain:

[0046]

[0047] Substituting equation (7) into equation (6) and eliminating R, we can derive the following:

[0048]

[0049] From equation (5), we can obtain:

[0050]

[0051] Substituting equations (4) and (7) into equation (9), we get:

[0052]

[0053] From equation (5), then Right now:

[0054]

[0055] The final basic formula for solving the two-layer equivalent channel is as follows:

[0056]

[0057] With the aid of equations (7) and (11), the system of equations can be solved.

[0058] In the formula, R is the hydraulic radius function, m, i0 is the channel gradient, n is the roughness coefficient, L is the length of the sub-section, α is the average velocity-to-wave velocity coefficient, K2 and X2 are the parameters of the sub-section in the Muskingan method of the two-layer equivalent channel, Q2 is the peak flow rate of the two-layer equivalent channel, and m 3 / s, F(H) is the cross-sectional area, H is the maximum water depth of the double-layer equivalent channel cross-section, B is the width of the double-layer equivalent channel in m, F(H) is the partial derivative of the cross-sectional area function F(H) with respect to H, and R′ is the partial derivative of the hydraulic radius function R(H) with respect to H.

[0059] After determining the relationship between the maximum water depth H and the cross-sectional area F(H) of the double-layer equivalent channel, the function of the second-level cross-sectional shape F(H) with respect to the water depth H and shape parameters a and b is substituted into the above formula for solution.

[0060] The second-level river channel curve can be set as exponential: B = bH2 a +B1; The second-level channel curve can also be set to other forms, for example, when the second-level channel curve is parabolic: When the second-level river channel curve is trapezoidal: B = bH2 + a + B1.

[0061] In one embodiment, such as Figure 2 As shown, the second-level river channel curve is set as exponential, B = bH2. a +B1. Where a and b are shape parameters, and B1 is the river width of the first level.

[0062] From B = bH2 a +B1, then:

[0063]

[0064] Combining equation (6) and equation (10), we get:

[0065]

[0066] A1 represents the equivalent cross-sectional area of ​​the first-level river channel.

[0067] From equation (9), we get:

[0068]

[0069] Differentiating B, we get: B'(H) = abH2 a-1 From equation (11), we can obtain but:

[0070]

[0071] Based on equations (14), (15), and (16), the cross-sectional water depth H and the two shape parameters a and b can be solved.

[0072] The hydrodynamic model obtained from the above transformation, which includes river width B, channel gradient i0, and cross-sectional water depth H, can be used for hydrological prediction.

[0073] In one example, Muskingan data from the Yellow River's Huayuankou to Jiahetan section is used to generate a two-layer equivalent channel. The total length of the Yellow River from Huayuankou to Jiahetan is 105.4 km, K1 = 5, X1 = 0.3, and Q1 = 5000 m. 3 / s; K2 = 4.5, X2 = 0, Q2 = 20000m 3 / s. The cross-sectional shape of the first layer of equivalent river channel is set to parabolic, and the second layer defaults to an exponential cross-section. The generated two-layer equivalent river channel is as follows: Figure 3 As shown.

[0074] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the calculation method for converting Muskinggan parameters into a two-layer equivalent channel.

[0075] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the calculation method for converting Muskinggan parameters into a two-layer equivalent channel.

[0076] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0077] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0078] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

Claims

1. A calculation method based on Muskingan method parameter conversion to a two-layer equivalent channel, characterized in that, Includes the following steps: (1) The actual river with nonlinear characteristics is decomposed into two single-layer equivalent rivers. The lower layer of the two single-layer equivalent rivers is the first layer of equivalent rivers, and the higher layer of the two single-layer equivalent rivers is the second layer of equivalent rivers. The width of the first layer of equivalent rivers is equal to the width of the bottom of the second layer of equivalent rivers. The gradient of the two single-layer equivalent rivers is set to be equal. (2) Based on the formula for calculating the single-layer equivalent channel and the parameters of the first-layer equivalent channel, the maximum water depth of the first-layer equivalent channel is calculated. River width gradient with the river channel ; (3) Based on the maximum water depth, river width and river gradient of the first equivalent channel, set the cross-sectional shape of the second equivalent channel as a function F with respect to water depth and shape parameters. Combine the relationship between water depth and cross-sectional shape function F of the two equivalent channels to solve the shape parameter value, maximum water depth H and river width B of the two equivalent channels. The double-layer equivalent channel depth and cross-sectional shape function mentioned in step (3) The relation is: ； in: , ; In the formula, It is a hydraulic radius function. For the riverbed gradient, For roughness, To divide the river section length, The average flow velocity to wave velocity conversion coefficient. The parameters for the Muskingan method of dividing the river into two equivalent channels are given. This represents the cross-sectional flow rate of the river flood peak at two equivalent levels. It is a function of cross-sectional area. The maximum water depth is the equivalent cross-section of the double-layered river channel. For the double-layer equivalent river channel width, The cross-sectional area function Taking the partial derivative with respect to water depth, hydraulic radius function Take the partial derivative with respect to water depth; Based on the cross-sectional shape of the second-level equivalent river channel as a function of water depth and shape parameters... And the double-layer equivalent channel depth and cross-sectional shape function The relationship is used to derive the shape parameters of the double-layer equivalent river channel. Maximum water depth H and river width The calculation formula: ； In the formula, For the riverbed gradient, For roughness, To divide the river section length, The average flow velocity to wave velocity conversion coefficient. The parameters for the Muskingan method of dividing the river into two equivalent channels are given. This represents the cross-sectional flow rate of the river flood peak at two equivalent levels. The maximum water depth is the equivalent cross-section of the double-layered river channel. For the double-layer equivalent river channel width, This represents the maximum water depth of the second-level equivalent river channel cross-section. ,in The maximum water depth of the first equivalent channel. The width of the first-level equivalent river channel. This represents the equivalent cross-sectional area of ​​the first-level river channel. The shape parameters of the double-layer equivalent river channel.

2. The calculation method based on Muskingan method parameter conversion to a two-layer equivalent channel as described in claim 1, characterized in that: The formula for calculating the single-layer equivalent river channel mentioned in step (2) is as follows: ； In the formula, Let R be the hydraulic radius, and R be the width of the river. Having a functional relationship R=g( ), For the riverbed gradient, For roughness, The length of the river channel. The average flow velocity to wave velocity conversion coefficient. The parameters for the first layer of equivalent river channel using the Muskingan method are as follows: The first layer is the equivalent peak flow of the river channel. This represents the equivalent cross-sectional area of ​​the first-level river channel. The maximum water depth of the first-level equivalent river channel cross-section. The first layer is the equivalent cross-sectional area function of the river channel. Taking the partial derivative with respect to water depth, hydraulic radius function Take the partial derivative with respect to water depth.

3. The calculation method based on Muskingan method parameter conversion to a two-layer equivalent channel as described in claim 1, characterized in that: The function relating the cross-sectional shape of the second-layer equivalent channel to the water depth and shape parameters described in step (3) is as follows: When the second-level river channel curve is exponential, the function is... for: , This represents the maximum water depth of the second-level equivalent river channel cross-section. The width of the first-level equivalent river channel. The shape parameters of the two-layer equivalent river channel. It represents the width of a double-layered equivalent river channel.

4. The calculation method based on Muskingan method parameter conversion to a two-layer equivalent channel as described in claim 1, characterized in that: The function relating the cross-sectional shape of the second-layer equivalent channel to the water depth and shape parameters described in step (3) is as follows: When the second-level river channel curve is parabolic, the function is... for: , This represents the maximum water depth of the second-level equivalent river channel cross-section. The width of the first-level equivalent river channel. The shape parameters of the two-layer equivalent river channel. It represents the width of a double-layered equivalent river channel.

5. The calculation method based on Muskingan method parameter conversion to a two-layer equivalent channel as described in claim 1, characterized in that: The function relating the cross-sectional shape of the second-layer equivalent channel to the water depth and shape parameters described in step (3) is as follows: When the second-level river channel curve is trapezoidal, the function... for: , This represents the maximum water depth of the second-level equivalent river channel cross-section. The width of the first-level equivalent river channel. The shape parameters of the two-layer equivalent river channel. It represents the width of a double-layered equivalent river channel.

6. The calculation method based on Muskingan method parameter conversion to a two-layer equivalent channel as described in claim 1, characterized in that: By default, the cross-sectional shape of the first layer of equivalent river channels is set to parabolic, and the cross-sectional shape of the second layer of equivalent river channels is set to exponential.

7. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the calculation method for converting parameters based on the Muskingan method into a two-layer equivalent channel, as described in any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the calculation method for converting the parameters based on the Muskingan method into a two-layer equivalent channel, as described in any one of claims 1 to 6.

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