A method and system for calculating the basic flow required to maintain the dimensions of a compound cross-section channel

Abstract

The application belongs to the professional field of river dynamics and waterway engineering, and discloses a calculation method and system for maintaining basic flow required by waterway scale of compound section, which comprises the following steps: data collection; determining waterway overall construction parameters; determining waterway inlet section shape and hydraulic parameters; determining waterway inlet section water surface slope; calculating initial value of basic flow required by waterway scale of waterway inlet section; simulating and calculating actual water depth along the waterway according to the initial value of the basic flow; judging whether the basic flow meets the water depth requirement of the waterway according to the actual water depth; if yes, the basic flow required by waterway scale of the compound section is obtained; if not, the flow is corrected. The application can provide reference for tributary waterway planning and design, rapid determination and in-depth study of waterway basic flow.

Description

Technical Field

[0001] This invention relates to the technical field of river dynamics and waterway engineering, specifically to a method and system for calculating the basic flow required to maintain the dimensions of a complex cross-section waterway. Background Technology

[0002] Inland waterway transportation is an important component of the comprehensive transportation system and the comprehensive utilization of water resources. It has advantages such as large transport capacity, low energy consumption, and green and low-carbon characteristics. Effective integration with other modes of transportation is conducive to optimizing the transportation structure and accelerating the construction of a modern comprehensive transportation system. When developing tributary waterways, determining the basic flow rate required to maintain the channel dimensions is a fundamental prerequisite for their development and construction. However, the cross-section of tributary waterways is often a complex cross-section, unlike artificial channels. The required flow rate varies with complex river characteristics, topography, and upstream and downstream hydrological conditions. Conventional methods require extensive trial calculations using a combination of hydrological and topographical models to determine the required flow rate. To ensure the channel dimensions are met, a quantitative relationship between flow rate and navigation depth needs to be derived. Currently, there is no mature and convenient calculation method.

[0003] To address this problem, this invention, for the first time, comprehensively considers changes in river characteristics, topography, and hydrological conditions, and proposes a relatively accurate and rapid theoretical calculation method for determining the basic flow required to maintain a complex cross-section waterway scale. Summary of the Invention

[0004] To address the above technical problems, this invention provides a method and system for calculating the basic flow required to maintain the dimensions of a complex cross-section waterway, which can provide a reference for the planning and design of tributary waterways and the rapid determination and in-depth study of basic waterway flow.

[0005] This invention provides a method for calculating the basic flow rate required to maintain the dimensions of a complex cross-section waterway, the method comprising:

[0006] S1: Collect information on the proposed waterway construction, river topography, and upstream and downstream hydrological conditions;

[0007] S2: Based on the proposed waterway construction data, determine the overall construction parameters of the waterway, including the waterway depth, waterway bottom width, waterway slope coefficient, waterway mileage, and waterway longitudinal gradient.

[0008] S3: Based on the aforementioned river topographic data and the overall construction status of the waterway, the morphology and hydraulic parameters of the waterway inlet section are determined, with the upstream inlet section as the control section. The waterway section is a compound section, and the hydraulic parameters include the side bar depth, side bar width, riverbank slope coefficient, wetted perimeter of the channel and side bar, and corresponding roughness coefficient. Based on the overall construction parameters of the waterway, the morphology of the waterway inlet section, and the hydraulic parameters, the flow area, wetted perimeter, and comprehensive roughness coefficient below the boundary water level of the waterway inlet section are calculated to maintain the waterway dimensions.

[0009] S4: Based on the upstream and downstream hydrological conditions, determine the starting elevation of dredging at the downstream outlet section of the channel and the corresponding outlet water level, and calculate the water level gradient at the inlet section of the channel in conjunction with the longitudinal gradient of the channel bed.

[0010] S5: Calculate the basic flow rate at the channel inlet section to maintain channel dimensions based on the flow area, wetted perimeter, comprehensive roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions.

[0011] S6: Based on the river topography data and waterway construction, and using the theory of computational river dynamics, establish a two-dimensional planar mathematical model of river flow. Based on the two-dimensional planar mathematical model of river flow, calculate the water depth distribution along the waterway and obtain the minimum water depth of the waterway.

[0012] S7: Determine whether the absolute value of the difference between the minimum channel depth and the channel depth scale exceeds the preset depth threshold; if not, determine that the basic flow rate at the channel inlet section to maintain the channel scale is the basic flow rate that can meet the channel scale; if yes, proceed to S8 for correction.

[0013] S8: Correct the basic flow rate required to maintain the dimensions of the complex cross-section waterway.

[0014] Preferably, based on the overall construction parameters of the waterway, the cross-sectional shape of the waterway inlet, and the hydraulic parameters, the calculation of the flow area, wetted perimeter, and overall roughness below the boundary water level of the waterway inlet cross-section to maintain the waterway dimensions includes:

[0015]

[0016] Where A is the flow area below the boundary water level of the channel inlet section when maintaining the channel dimensions, χ is the wetted perimeter below the boundary water level of the channel inlet section when maintaining the channel dimensions, n is the comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions, H is the channel depth scale, B is the channel bottom width, m is the channel side slope coefficient, i is the longitudinal gradient of the channel bed, and α is the channel slope. i H represents the water depth at the beach, b i The width of the beach is in meters. i χ is the riverbank slope coefficient. i For the wetted perimeter of the channel and the beach, ni The wetted perimeter roughness of the channel and the side beach is given.

[0017] Preferably, based on the upstream and downstream hydrological conditions, the dredging starting elevation and corresponding outlet water level of the downstream outlet section of the channel are determined, and the water level gradient of the channel inlet section is calculated in conjunction with the longitudinal gradient of the channel bed, including:

[0018] When the gradient of the channel bed is greater than the average water surface gradient,

[0019] When the gradient of the channel bed is less than the average water surface gradient

[0020] In the formula: H u =H+ΔH is the inlet channel depth, where ΔH is the difference between the channel depth and the channel depth scale; H d =Z d -Z0 represents the water depth of the exit channel; and The gradient correction coefficient, with a value range of [0, 1], approximates the degree of backwater or drawdown at the outlet water level. When the value is 0, J represents the longitudinal gradient of the channel bed; when the value is 1, J represents the average water surface gradient of the channel. Z0 represents the starting elevation of dredging at the downstream outlet section of the channel, and Z... d The elevation of the starting point for dredging at the downstream outlet section of the waterway corresponds to the outlet water level, and L is the waterway mileage.

[0021] Preferably, the basic flow rate for maintaining the channel dimensions at the channel inlet section is calculated based on the flow area, wetted perimeter, overall roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions.

[0022]

[0023] The present invention also provides a calculation system for the basic flow required to maintain the dimensions of a complex cross-section waterway. The system is used to implement the method described in any one of the above, and includes: an acquisition module, a first calculation module, a second calculation module, a third calculation module, a fourth calculation module, a fifth calculation module, a judgment module, and a correction module.

[0024] The acquisition module is used to collect information on the proposed waterway construction, river topography data, and upstream and downstream hydrological conditions.

[0025] The first calculation module is used to determine the overall construction parameters of the waterway based on the proposed waterway construction data. The overall construction parameters of the waterway include waterway depth, waterway bottom width, waterway slope coefficient, waterway mileage, and waterway longitudinal slope.

[0026] The second calculation module is used to determine the morphology and hydraulic parameters of the channel inlet section based on the river topography data and the overall channel construction, using the upstream inlet section as the control section. The channel section is a compound section, and the hydraulic parameters include the side bar depth, side bar width, riverbank slope coefficient, wetted perimeter of the channel and side bar, and corresponding roughness coefficient. Based on the overall channel construction parameters, the morphology of the channel inlet section, and the hydraulic parameters, the module calculates the flow area, wetted perimeter, and comprehensive roughness coefficient below the boundary water level of the channel inlet section while maintaining the channel dimensions.

[0027] The third calculation module is used to determine the dredging starting elevation and corresponding outlet water level of the downstream outlet section of the waterway based on the upstream and downstream hydrological conditions, and to calculate the water level gradient of the inlet section of the waterway in combination with the longitudinal gradient of the waterway bed.

[0028] The fourth calculation module is used to calculate the basic flow rate at the channel inlet section to maintain the channel scale based on the flow area below the boundary water level of the channel inlet section, wetted perimeter, comprehensive roughness and the water surface gradient of the channel inlet section when maintaining the channel scale.

[0029] The fifth calculation module is used to establish a two-dimensional plane flow mathematical model of the river channel based on the river topography data and waterway construction, and to calculate the water depth distribution along the waterway based on the two-dimensional plane flow mathematical model of the river channel, so as to obtain the minimum water depth of the waterway.

[0030] The judgment module is used to determine whether the absolute value of the difference between the minimum water depth of the channel and the water depth scale exceeds the preset water depth threshold; if not, it determines that the basic flow rate at the channel inlet section to maintain the waterway scale is the basic flow rate that can meet the waterway scale; if yes, it proceeds to the correction module for correction.

[0031] The correction module is used to correct the basic flow rate required to maintain the dimensions of the complex cross-section waterway.

[0032] Preferably, based on the overall construction parameters of the waterway, the cross-sectional shape of the waterway inlet, and the hydraulic parameters, the calculation of the flow area, wetted perimeter, and overall roughness below the boundary water level of the waterway inlet cross-section to maintain the waterway dimensions includes:

[0033]

[0034] Where A is the flow area below the boundary water level of the channel inlet section when maintaining the channel dimensions, χ is the wetted perimeter below the boundary water level of the channel inlet section when maintaining the channel dimensions, n is the comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions, H is the channel depth scale, B is the channel bottom width, m is the channel side slope coefficient, i is the longitudinal gradient of the channel bed, and α is the channel slope. i H represents the water depth at the beach, b i The width of the beach is in meters.i χ is the riverbank slope coefficient. i For the wetted perimeter of the channel and the beach, n i The wetted perimeter roughness of the channel and the side beach is given.

[0035] Preferably, based on the upstream and downstream hydrological conditions, the dredging starting elevation and corresponding outlet water level of the downstream outlet section of the channel are determined, and the water level gradient of the channel inlet section is calculated in conjunction with the longitudinal gradient of the channel bed, including:

[0036] When the gradient of the channel bed is greater than the average water surface gradient,

[0037] When the gradient of the channel bed is less than the average water surface gradient

[0038] In the formula: H u =H+ΔH is the inlet channel depth, where ΔH is the difference between the channel depth and the channel depth scale; H d =Z d -Z0 represents the water depth of the exit channel; and The gradient correction coefficient, with a value range of [0, 1], approximates the degree of backwater or drawdown at the outlet water level. When the value is 0, J represents the longitudinal gradient of the channel bed; when the value is 1, J represents the average water surface gradient of the channel. Z0 represents the starting elevation of dredging at the downstream outlet section of the channel, and Z... d The elevation of the starting point for dredging at the downstream outlet section of the waterway corresponds to the outlet water level, and L is the waterway mileage.

[0039] Preferably, the basic flow rate for maintaining the channel dimensions at the channel inlet section is calculated based on the flow area, wetted perimeter, overall roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions.

[0040]

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] Conventional methods require extensive hydrological and topographical simulations to determine the basic flow rate needed to maintain a complex cross-section channel scale. The advantage of the method proposed in this invention lies in its theoretical derivation, which calculates a preliminary theoretical value for the basic flow rate at the channel inlet cross-section to maintain the channel scale. This initial value generally closely approximates the final actual value. Further simulations can verify the results and improve accuracy, significantly enhancing computational efficiency. Therefore, the method proposed in this invention for calculating the basic flow rate required to maintain a complex cross-section channel scale can quickly and accurately calculate the basic flow rate required to meet the channel design standards under different topographical and upstream / downstream hydrological conditions. This provides technical support for tributary channel planning and design, and offers a reference for the rapid determination and in-depth study of basic channel flow rates. Attached Figure Description

[0043] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a simplified schematic diagram of the cross-sectional shape of the river channel and waterway inlet according to an embodiment of the present invention;

[0045] Figure 2 This is a simplified schematic diagram of a river channel and waterway according to an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of riverbed and waterway degradation according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of riverbed and waterway degradation according to an embodiment of the present invention;

[0048] Figure 5 This is a schematic diagram of a method for calculating the basic flow required to maintain the dimensions of a complex cross-section waterway according to an embodiment of the present invention.

[0049] Figure 6 This is a schematic diagram of the channel inlet cross-sectional shape according to an embodiment of the present invention;

[0050] Figure 7 This is a schematic diagram of the longitudinal profile of the waterway and the water level distribution upstream and downstream, according to an embodiment of the present invention.

[0051] Figure 8 This is a schematic diagram illustrating the establishment of a two-dimensional planar water flow mathematical model according to an embodiment of the present invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Example 1

[0056] This invention provides a method for calculating the basic flow rate required to maintain the dimensions of a complex cross-section waterway, the method comprising:

[0057] S1: Collect relevant data such as proposed waterway construction information, river topographic data, and upstream and downstream hydrological conditions;

[0058] S2: Based on the proposed waterway construction data, determine the overall construction parameters of the waterway, including the waterway depth, waterway bottom width, waterway slope coefficient, waterway mileage, and waterway longitudinal gradient.

[0059] S3: Based on the aforementioned river topographic data and the overall construction status of the waterway, the morphology and hydraulic parameters of the waterway inlet section are determined, with the upstream inlet section as the control section. The waterway section is a compound section, and the hydraulic parameters include the side bar depth, side bar width, riverbank slope coefficient, wetted perimeter of the channel and side bar, and corresponding roughness coefficient. Based on the overall construction parameters of the waterway, the morphology of the waterway inlet section, and the hydraulic parameters, the flow area, wetted perimeter, and comprehensive roughness coefficient below the boundary water level of the waterway inlet section are calculated to maintain the waterway dimensions.

[0060] S4: Based on the upstream and downstream hydrological conditions, determine the starting elevation of dredging at the downstream outlet section of the channel and the corresponding outlet water level, and calculate the water level gradient at the inlet section of the channel in conjunction with the longitudinal gradient of the channel bed.

[0061] S5: Calculate the basic flow rate at the channel inlet section to maintain channel dimensions based on the flow area, wetted perimeter, comprehensive roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions.

[0062] S6: Based on the river topography data and waterway construction, and using the theory of computational river dynamics, establish a two-dimensional planar mathematical model of river flow. Based on the two-dimensional planar mathematical model of river flow, calculate the water depth distribution along the waterway and obtain the minimum water depth of the waterway.

[0063] S7: Determine whether the absolute value of the difference between the minimum channel depth and the channel depth scale exceeds the preset depth threshold; if not, determine that the basic flow rate at the channel inlet section to maintain the channel scale is the basic flow rate that can meet the channel scale; if yes, proceed to S8 for correction.

[0064] S8: Correct the basic flow rate required to maintain the dimensions of the complex cross-section waterway.

[0065] In this embodiment, the flow rate of the target channel is calculated according to the following formula:

[0066]

[0067] Where Q is the basic flow rate at the channel inlet section to maintain the channel dimensions; n1 is the comprehensive roughness below the boundary water level at the channel inlet section when maintaining the channel dimensions; J is the water surface gradient at the channel inlet section; H is the channel depth dimension; B is the channel bottom width; and m is the channel slope coefficient.

[0068] In this embodiment, to derive the basic flow rate required to meet the channel dimensions, a basic formula is derived based on Manning's formula:

[0069]

[0070] The generalization is based on the actual natural conditions of the waterway and riverbed, such as... Figure 1

[0071] The channel bottom width is B, the channel depth is H, the channel side slope coefficient is m, and the channel roughness coefficient is n0.

[0072] The widths outside the navigation channel on the left and right sides of the river channel are b1 and b2, respectively; the slope coefficients are m1 and m2, respectively; and the roughness coefficients are n1 and n2, respectively.

[0073] The water depths on the left and right sides of the river channel are α1H and α2H, respectively (0≤α1, α2≤1).

[0074] Calculations are performed based on generalized cross-sectional parameters:

[0075]

[0076] Substituting equations (3) to (8) into equation (2), we can obtain the formula for the flow rate corresponding to the navigation depth under the generalized cross-section of a waterway or river channel, as shown in equation (9):

[0077]

[0078] Simplification: After long-term scouring, the bottom of a river channel tends to be flat, which can be simplified to a trapezoidal cross-section. Furthermore, the navigation channel design aims for symmetrical distribution from left to right. Figure 1 It can be simplified as follows Figure 2 .

[0079] That is: b2=b1, m2=m1, n2=n1, α2=α1=α

[0080] but:

[0081] A0 = BH + mH 2 (1-α 2 (10)

[0082]

[0083] A1+A2=2b1αH+m1α 2 H 2 (12)

[0084]

[0085] Substituting equations (10) to (13) into equation (2) yields the simplified formulas for the flow rate corresponding to the navigation depth under the channel and riverbed cross-sections, as shown in equation (14):

[0086]

[0087] Degradation 1: The channel is completely below the riverbed bottom (fully dredged channel). In this case, the channel depth is entirely determined by the channel cross-sectional parameters and is not affected by the riverbed morphology. The channel cross-section is as follows: Figure 3 Show.

[0088] That is, α=0, b1=b2=0, substituting into equation (14), we can obtain the formulas for the channel depth and the required flow rate under this condition as shown in equation (15):

[0089]

[0090] Degradation 2: The channel is completely above the riverbed bottom (without dredging). In this case, the channel depth is no longer affected by the channel cross-sectional parameters; the relationship between channel depth and flow rate is determined only by the riverbed morphology and roughness. The channel cross-section is as follows: Figure 4 Show.

[0091] That is: α=1, B=0, b=2b1, substituting into equation (14), we obtain the formula for the channel depth and the required flow rate under this condition as shown in equation (16):

[0092]

[0093] In this embodiment, based on the overall construction parameters of the waterway, the cross-sectional shape of the waterway inlet, and the hydraulic parameters, the calculation of the flow area, wetted perimeter, and overall roughness below the boundary water level of the waterway inlet cross-section while maintaining the waterway dimensions includes:

[0094]

[0095] Where A is the flow area below the boundary water level of the channel inlet section when maintaining the channel dimensions, χ is the wetted perimeter below the boundary water level of the channel inlet section when maintaining the channel dimensions, n is the comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions, H is the channel depth scale, B is the channel bottom width, m is the channel side slope coefficient, i is the longitudinal gradient of the channel bed, and α is the channel slope. i H represents the water depth at the beach, b i The width of the beach is in meters. i χ is the riverbank slope coefficient. i For the wetted perimeter of the channel and the beach, n i The wetted perimeter roughness of the channel and the side beach is given.

[0096] If the roughness of the inlet section of the channel and the beach is difficult to determine, it can be replaced by the roughness determined by the flood survey data.

[0097] In this embodiment, based on the upstream and downstream hydrological conditions, the dredging starting elevation and corresponding outlet water level of the downstream outlet section of the channel are determined. Combined with the longitudinal gradient of the channel bed, the water level gradient of the channel inlet section is calculated, including:

[0098] When the gradient of the channel bed is greater than the average water surface gradient,

[0099] When the gradient of the channel bed is less than the average water surface gradient

[0100] In the formula: H u =H+ΔH is the inlet channel depth, where ΔH is the difference between the channel depth and the channel depth scale; H d =Z d -Z0 represents the water depth of the exit channel; and The gradient correction coefficient, with a value range of [0, 1], approximates the degree of backwater or drawdown at the outlet water level. When the value is 0, J represents the longitudinal gradient of the channel bed; when the value is 1, J represents the average water surface gradient of the channel. Z0 represents the starting elevation of dredging at the downstream outlet section of the channel, and Z... d The elevation of the starting point for dredging at the downstream outlet section of the waterway corresponds to the outlet water level, and L is the waterway mileage.

[0101] If the water level at the channel outlet is not specified or is unknown, then the discharge will proceed as approximately uniform. d =H, at this time Z d The required basic flow rate is obtained by converting the water level-flow rate relationship (Z-Q relationship) at the downstream outlet.

[0102] In this embodiment, the basic flow rate for maintaining the channel dimensions at the channel inlet section is calculated based on the flow area, wetted perimeter, overall roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions.

[0103]

[0104] In this embodiment, based on river topographic data and waterway construction, and using computational river dynamics theory, a two-dimensional planar flow mathematical model of the river is established. The flow rate initially determined in S5 is used as the upstream inlet flow rate of the model, and the outlet water level Z in S5 is used as the model's flow rate. d As the downstream outlet water level Z of the model out Calculate the water depth distribution along the channel to obtain the minimum water depth H of the channel. 实际 The two-dimensional mathematical model of river flow in the plane includes:

[0105]

[0106] Where x and y are Cartesian coordinates; t is the time variable; Z is the water level; M = uh, N = vh, u is the flow velocity in the x-direction, v is the flow velocity in the y-direction, and h is the water depth; n2 is the Manning roughness coefficient; D is the turbulent viscosity coefficient; q is the flow rate per unit area of ​​the source and sink; u0 is the flow velocity in the x-direction when the source or sink enters or exits the channel; v0 is the flow velocity in the y-direction when the source or sink enters or exits the channel; and g is the gravitational acceleration.

[0107] In this embodiment, based on the calculation results of S6, it is determined whether the basic flow rate can meet the channel depth requirements. If |H 实际 -H|≤H 允许偏差 Then the flow rate Q is the basic flow rate that can meet the channel scale; if |H 实际 -H|>H 允许偏差 If so, proceed to S8 for correction.

[0108] In this embodiment, the correction method for calculating the basic flow rate required to maintain the complex cross-section channel dimensions is as follows:

[0109] If H 实际 >H: Then appropriately reduce the upstream flow rate Q, or simultaneously lower the outlet water level Z according to the water level-flow rate relationship. out H was recalculated using the two-dimensional planar hydrodynamic model in S6. 实际 The S7 judgment method is used to determine the basic flow required to maintain the dimensions of the complex cross-section waterway.

[0110] If H 实际 <H: Then appropriately increase the upstream flow rate Q, or simultaneously raise the outlet water level Z according to the water level-flow rate relationship. out H was recalculated using the two-dimensional planar hydrodynamic model in S6. 实际 The S7 judgment method is used to determine the basic flow required to maintain the dimensions of the complex cross-section waterway.

[0111] It should be noted that the method of this disclosure embodiment can be executed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario, where multiple devices cooperate to complete the task. In such a distributed scenario, one of these devices may execute only one or more steps of the method of this disclosure embodiment, and the multiple devices will interact with each other to complete the method described.

[0112] It should be noted that the above description describes some embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, it should be understood that the sequence number of each step in the above embodiments does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The actions or steps recorded in the claims can be performed in a different order than that in the above embodiments and can still achieve the desired result. In addition, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0113] Example 2

[0114] Based on the same inventive concept, corresponding to any of the above embodiments, this disclosure also provides a calculation system for the basic flow required to maintain the dimensions of a complex cross-section waterway. The system is used to implement the method described in any one of the above embodiments, and includes: an acquisition module, a first calculation module, a second calculation module, a third calculation module, a fourth calculation module, a fifth calculation module, a judgment module, and a correction module.

[0115] The acquisition module is used to collect data on the proposed waterway construction, river topography, and upstream and downstream hydrological conditions.

[0116] The first calculation module is used to determine the overall construction parameters of the waterway based on the proposed construction data of the waterway. The overall construction parameters of the waterway include the waterway depth, waterway bottom width, waterway slope coefficient, waterway mileage, and waterway longitudinal slope.

[0117] The second calculation module is used to determine the morphology and hydraulic parameters of the channel inlet section based on the river topography data and the overall channel construction, taking the upstream inlet section as the control section. The channel section is a compound section, and the hydraulic parameters include the side bar depth, side bar width, riverbank slope coefficient, wetted perimeter of the channel and side bar, and corresponding roughness coefficient. Based on the overall channel construction parameters, the morphology of the channel inlet section, and the hydraulic parameters, the module calculates the flow area, wetted perimeter, and comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions.

[0118] The third calculation module is used to determine the starting elevation of dredging at the downstream outlet section of the waterway and the corresponding outlet water level based on the upstream and downstream hydrological conditions, and to calculate the water level gradient at the inlet section of the waterway in conjunction with the longitudinal gradient of the waterway bed.

[0119] The fourth calculation module is used to calculate the basic flow rate at the channel inlet section to maintain the channel dimensions based on the flow area, wetted perimeter, comprehensive roughness, and water surface gradient of the channel inlet section below the boundary water level when maintaining the channel dimensions.

[0120] The fifth calculation module is used to establish a two-dimensional plane flow mathematical model of the river channel based on the river topography data and waterway construction, and on the basis of computational river dynamics theory. Based on the two-dimensional plane flow mathematical model of the river channel, the water depth distribution along the waterway is calculated to obtain the minimum water depth of the waterway.

[0121] The judgment module is used to determine whether the absolute value of the difference between the minimum water depth of the channel and the water depth scale exceeds the preset water depth threshold; if not, it determines that the basic flow rate at the channel inlet section to maintain the water depth scale is the basic flow rate that can meet the water depth scale; if yes, it goes to S8 for correction.

[0122] The correction module is used to correct the basic flow rate required to maintain the dimensions of the complex cross-section waterway.

[0123] In this embodiment, based on the overall construction parameters of the waterway, the cross-sectional shape of the waterway inlet, and the hydraulic parameters, the calculation of the flow area, wetted perimeter, and overall roughness below the boundary water level of the waterway inlet cross-section while maintaining the waterway dimensions includes:

[0124]

[0125] Where A is the flow area below the boundary water level of the channel inlet section when maintaining the channel dimensions, χ is the wetted perimeter below the boundary water level of the channel inlet section when maintaining the channel dimensions, n is the comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions, H is the channel depth scale, B is the channel bottom width, m is the channel side slope coefficient, i is the longitudinal gradient of the channel bed, and α is the channel slope. i H represents the water depth at the beach, b i The width of the beach is in meters. i χ is the riverbank slope coefficient. i For the wetted perimeter of the channel and the beach, n i The wetted perimeter roughness of the channel and the side beach is given.

[0126] In this embodiment, based on the upstream and downstream hydrological conditions, the dredging starting elevation and corresponding outlet water level of the downstream outlet section of the channel are determined. Combined with the longitudinal gradient of the channel bed, the water level gradient of the channel inlet section is calculated, including:

[0127] When the gradient of the channel bed is greater than the average water surface gradient,

[0128] When the gradient of the channel bed is less than the average water surface gradient

[0129] In the formula: H u =H+ΔH is the inlet channel depth, where ΔH is the difference between the channel depth and the channel depth scale; H d =Z d -Z0 represents the water depth of the exit channel; and The gradient correction coefficient, with a value range of [0, 1], approximates the degree of backwater or drawdown at the outlet water level. When the value is 0, J represents the longitudinal gradient of the channel bed; when the value is 1, J represents the average water surface gradient of the channel. Z0 represents the starting elevation of dredging at the downstream outlet section of the channel, and Z... d The elevation of the starting point for dredging at the downstream outlet section of the waterway corresponds to the outlet water level, and L is the waterway mileage.

[0130] In this embodiment, the basic flow rate for maintaining the channel dimensions at the channel inlet section is calculated based on the flow area, wetted perimeter, overall roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions.

[0131]

[0132] The system described in the above embodiments is used to implement a method for calculating the basic flow required to maintain the dimensions of a complex cross-section waterway in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0133] It should be noted that the aforementioned calculation system for the basic flow required to maintain the dimensions of a complex cross-section waterway is embodied in the form of functional units. The term "module" here can be implemented in software and / or hardware, without specific limitations.

[0134] For example, a "module" can be a software program, hardware circuit, or a combination of both that implements the above functions. Hardware circuits may include application-specific integrated circuits (ASICs), electronic circuits, processors (e.g., shared processors, proprietary processors, or group processors) and memory for executing one or more software or firmware programs, combined logic circuits, and / or other suitable components that support the described functions.

[0135] Example 3

[0136] To make the solution of the present invention clearer, specific examples are further disclosed in the embodiments of the present invention.

[0137] (1) Collected relevant data on the proposed construction of a tributary waterway, river topography, and upstream and downstream hydrological conditions.

[0138] (2) A Class IV waterway is planned to be constructed on this tributary. Since the design bottom elevation of the waterway inlet section is higher than the original river elevation, the basic flow rate is controlled by the original river topography. The relevant overall construction parameters are as follows: the longitudinal ratio of the waterway bed is reduced to -0.00056.

[0139] (3) The cross-sectional morphology of the channel inlet is shown in the figure. Figure 6 The calculated flow area below the design water level of 27.45m at the channel inlet section is 2072m². 2 The wetted perimeter is 835m, and the overall roughness rate is 0.032 according to flood survey data.

[0140] (4) The dredging bottom elevation at the downstream outlet section of the channel is 22.89m, corresponding to the channel outlet water level Z. d The channel depth is 25.99m, with inlet and outlet depths of 5.12m and 3.1m respectively. The average water surface gradient is 0.000146, which is greater than the channel bed gradient. Therefore, the water surface gradient at the channel inlet section is... like Figure 7 As shown.

[0141] (5) Based on the parameters of the channel inlet section, calculate the initial basic flow rate at the channel inlet section to maintain the channel scale.

[0142] (6) Based on the river topography and waterway construction data, and based on the theory of computational river dynamics, a two-dimensional planar flow mathematical model of the river is established. The initial flow rate determined in step (5) is used as the upstream inlet flow rate of the model, and the outlet water level Z in step (4) is used as the model.d As the downstream outlet water level Z of the model out Calculate the water depth distribution along the channel to obtain the minimum water depth H of the channel. 实际 It is 3.06m. For example... Figure 8 As shown.

[0143] (7) Based on the calculation results of step (6), determine whether the basic flow rate can meet the channel depth requirements along the route. |H 实际 -H|=|3.06-3.10|=0.04m≤H 允许偏差 =0.05m, that is, the flow rate Q = 581m³ 3 / s represents the basic flow rate required to maintain this waterway scale.

[0144] The embodiments of this invention are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for calculating the basic flow rate required to maintain a complex cross-section waterway scale, characterized in that, The method includes: S1: Collect information on the proposed waterway construction, river topography, and upstream and downstream hydrological conditions; S2: Based on the proposed waterway construction data, determine the overall construction parameters of the waterway, including the waterway depth, waterway bottom width, waterway slope coefficient, waterway mileage, and waterway longitudinal gradient. S3: Based on the aforementioned river topographic data and the overall construction status of the waterway, the morphology and hydraulic parameters of the waterway inlet section are determined, with the upstream inlet section as the control section. The waterway section is a compound section, and the hydraulic parameters include the side bar depth, side bar width, riverbank slope coefficient, wetted perimeter of the channel and side bar, and corresponding roughness coefficient. Based on the overall construction parameters of the waterway, the morphology of the waterway inlet section, and the hydraulic parameters, the flow area, wetted perimeter, and comprehensive roughness coefficient below the boundary water level of the waterway inlet section are calculated to maintain the waterway dimensions. S4: Based on the upstream and downstream hydrological conditions, determine the starting elevation of dredging at the downstream outlet section of the channel and the corresponding outlet water level, and calculate the water level gradient at the inlet section of the channel in conjunction with the longitudinal gradient of the channel bed. S5: Calculate the basic flow rate at the channel inlet section to maintain channel dimensions based on the flow area, wetted perimeter, comprehensive roughness, and water surface gradient below the boundary water level of the channel inlet section when maintaining channel dimensions. S6: Based on the river topography data and waterway construction, and using the theory of computational river dynamics, establish a two-dimensional planar mathematical model of river flow. Based on the two-dimensional planar mathematical model of river flow, calculate the water depth distribution along the waterway and obtain the minimum water depth of the waterway. S7: Determine whether the absolute value of the difference between the minimum channel depth and the channel depth scale exceeds the preset depth threshold; if not, determine that the basic flow rate at the channel inlet section to maintain the channel scale is the basic flow rate that can meet the channel scale; if yes, proceed to S8 for correction. S8: Correct the basic flow rate required to maintain the dimensions of the complex cross-section waterway.

2. The method according to claim 1, characterized in that, Based on the overall construction parameters of the waterway, the cross-sectional shape of the waterway inlet, and the hydraulic parameters, the flow area, wetted perimeter, and overall roughness below the boundary water level of the waterway inlet section are calculated to maintain the waterway dimensions, including: Where A is the flow area below the boundary water level of the channel inlet section when maintaining the channel dimensions, χ is the wetted perimeter below the boundary water level of the channel inlet section when maintaining the channel dimensions, n is the comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions, H is the channel depth scale, B is the channel bottom width, m is the channel side slope coefficient, i is the longitudinal gradient of the channel bed, and α is the channel slope. i H represents the water depth at the beach, b i The width of the beach is in meters. i χ is the riverbank slope coefficient. i For the wetted perimeter of the channel and the beach, n i The wetted perimeter roughness of the channel and the side beach is given.

3. The method according to claim 2, characterized in that, Based on the upstream and downstream hydrological conditions, the dredging starting elevation and corresponding outlet water level at the downstream outlet section of the channel are determined. Combined with the longitudinal gradient of the channel bed, the water level gradient at the channel inlet section is calculated, including: When the gradient of the channel bed is greater than the average water surface gradient, When the gradient of the channel bed is less than the average water surface gradient In the formula: H u =H+ΔH is the inlet channel depth, where ΔH is the difference between the channel depth and the channel depth scale; H d =Z d -Z0 represents the water depth of the exit channel; and The gradient correction coefficient, with a value range of [0, 1], approximates the degree of backwater or drawdown at the outlet water level. When the value is 0, J represents the longitudinal gradient of the channel bed; when the value is 1, J represents the average water surface gradient of the channel. Z0 represents the starting elevation of dredging at the downstream outlet section of the channel, and Z... d The elevation of the starting point for dredging at the downstream outlet section of the waterway corresponds to the outlet water level, and L is the waterway mileage.

4. The method according to claim 3, characterized in that, Based on the flow area, wetted perimeter, overall roughness, and water surface gradient of the channel inlet section below the boundary water level when maintaining channel dimensions, the basic flow rate for maintaining channel dimensions at the channel inlet section includes:

5. A calculation system for the basic flow rate required to maintain a complex cross-section waterway scale, said system being used to implement the method described in any one of claims 1-4, characterized in that, include: The module includes an acquisition module, a first calculation module, a second calculation module, a third calculation module, a fourth calculation module, a fifth calculation module, a judgment module, and a correction module. The acquisition module is used to collect information on the proposed waterway construction, river topography data, and upstream and downstream hydrological conditions. The first calculation module is used to determine the overall construction parameters of the waterway based on the proposed waterway construction data. The overall construction parameters of the waterway include waterway depth, waterway bottom width, waterway slope coefficient, waterway mileage, and waterway longitudinal slope. The second calculation module is used to determine the morphology and hydraulic parameters of the channel inlet section based on the river topography data and the overall channel construction, using the upstream inlet section as the control section. The channel section is a compound section, and the hydraulic parameters include the side bar depth, side bar width, riverbank slope coefficient, wetted perimeter of the channel and side bar, and corresponding roughness coefficient. Based on the overall channel construction parameters, the morphology of the channel inlet section, and the hydraulic parameters, the module calculates the flow area, wetted perimeter, and comprehensive roughness coefficient below the boundary water level of the channel inlet section while maintaining the channel dimensions. The third calculation module is used to determine the dredging starting elevation and corresponding outlet water level of the downstream outlet section of the waterway based on the upstream and downstream hydrological conditions, and to calculate the water level gradient of the inlet section of the waterway in combination with the longitudinal gradient of the waterway bed. The fourth calculation module is used to calculate the basic flow rate at the channel inlet section to maintain the channel scale based on the flow area below the boundary water level of the channel inlet section, wetted perimeter, comprehensive roughness and the water surface gradient of the channel inlet section when maintaining the channel scale. The fifth calculation module is used to establish a two-dimensional plane flow mathematical model of the river channel based on the river topography data and waterway construction, and to calculate the water depth distribution along the waterway based on the two-dimensional plane flow mathematical model of the river channel, so as to obtain the minimum water depth of the waterway. The judgment module is used to determine whether the absolute value of the difference between the minimum water depth of the channel and the water depth scale exceeds the preset water depth threshold; if not, it determines that the basic flow rate at the channel inlet section to maintain the waterway scale is the basic flow rate that can meet the waterway scale; if yes, it proceeds to the correction module for correction. The correction module is used to correct the basic flow rate required to maintain the dimensions of the complex cross-section waterway.

6. The system according to claim 5, characterized in that, Based on the overall construction parameters of the waterway, the cross-sectional shape of the waterway inlet, and the hydraulic parameters, the flow area, wetted perimeter, and overall roughness below the boundary water level of the waterway inlet section are calculated to maintain the waterway dimensions, including: Where A is the flow area below the boundary water level of the channel inlet section when maintaining the channel dimensions, χ is the wetted perimeter below the boundary water level of the channel inlet section when maintaining the channel dimensions, n is the comprehensive roughness coefficient below the boundary water level of the channel inlet section when maintaining the channel dimensions, H is the channel depth scale, B is the channel bottom width, m is the channel side slope coefficient, i is the longitudinal gradient of the channel bed, and α is the channel slope. i H represents the water depth at the beach, b i The width of the beach is in meters. i χ is the riverbank slope coefficient. i For the wetted perimeter of the channel and the beach, n i The wetted perimeter roughness of the channel and the side beach is given.

7. The system according to claim 6, characterized in that, Based on the upstream and downstream hydrological conditions, the dredging starting elevation and corresponding outlet water level at the downstream outlet section of the channel are determined. Combined with the longitudinal gradient of the channel bed, the water level gradient at the channel inlet section is calculated, including: When the gradient of the channel bed is greater than the average water surface gradient, When the gradient of the channel bed is less than the average water surface gradient In the formula: H u =H+ΔH is the inlet channel depth, where ΔH is the difference between the channel depth and the channel depth scale; H d =Z d -Z0 represents the water depth of the exit channel; and The gradient correction coefficient, with a value range of [0, 1], approximates the degree of backwater or drawdown at the outlet water level. When the value is 0, J represents the longitudinal gradient of the channel bed; when the value is 1, J represents the average water surface gradient of the channel. Z0 represents the starting elevation of dredging at the downstream outlet section of the channel, and Z... d The elevation of the starting point for dredging at the downstream outlet section of the waterway corresponds to the outlet water level, and L is the waterway mileage.

8. The system according to claim 7, characterized in that, Based on the flow area, wetted perimeter, overall roughness, and water surface gradient of the channel inlet section below the boundary water level when maintaining channel dimensions, the basic flow rate for maintaining channel dimensions at the channel inlet section includes:

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