River cross section flow field reconstruction method, equipment, medium and product

Abstract

The invention discloses a river channel cross section flow field reconstruction method and device, a medium and a product, and relates to the technical field of hydrographic survey, and the method comprises the steps: determining a river channel cross section entropy parameter through employing an entropy theory formula according to a river reach historical hydraulic parameter; acquiring surface flow velocities at different positions of the cross section of the river channel by using non-contact measurement equipment; according to the channel cross section entropy parameters and the surface flow velocity time series data, adopting an entropy theory flow velocity distribution formula and utilizing a particle swarm optimization algorithm to solve an equation set, and determining the longitudinal flow velocity of the channel cross section; utilizing a two-dimensional interp2 interpolation algorithm to obtain flow velocity field data of the cross section of the river channel; and determining the flow of the river cross section by adopting a velocity area method according to the flow velocity field data of the river cross section. According to the method, the existing non-contact measurement technology can be fully utilized, the flow velocity field and the flow of the river channel are accurately determined, the measurement efficiency and accuracy are greatly improved, and the consumption of manpower and material resources is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of hydrological measurement, and particularly to a method, device, medium and product for reconstructing the cross-sectional flow field of a river channel. Background Art

[0002] The flow velocity and flow rate of a river are basic monitoring elements in the fields of flood control, water ecology, etc., and are indispensable basic data for aspects such as water resources management, flood risk control, and water environment governance. However, the measurement of river hydrological data often faces significant challenges. The traditional method of measuring flow using a moving acoustic Doppler current profiler relies on manual operation and shipborne measurement, which is not only costly and time-consuming, but also poses a major hidden danger to the life and property safety of the flow measurement workers, affecting the normal development of flow measurement work during floods. In addition, the discontinuous data obtained by moving flow measurement cannot continuously monitor the changes in river hydrodynamics, which greatly restricts the construction of a digital twin watershed. Therefore, there is an urgent need to explore an efficient, low-cost and safe flow measurement method.

[0003] With the continuous development of sensors and embedded systems, non-contact measurement methods for rivers have been successively proposed, and the water measurement technology has been further improved. Based on this development, non-contact flow measurement technologies such as acoustic waves, electromagnetic waves, and image processing can remotely measure the surface velocity of water bodies and are gradually becoming important tools for hydrological monitoring. These technologies avoid direct contact with water bodies, improve the safety of measurement work, and show obvious advantages in hydrological monitoring. As two main methods of non-contact flow measurement technology, the radar method and the image method have been widely used in the field of hydrological monitoring. Compared with contact flow measurement technology, non-contact flow measurement technology can complete measurement work that cannot be completed by humans in the harsh field environment and can achieve all-weather real-time online monitoring, greatly ensuring water safety and data integrity.

[0004] Although the current non-contact flow measurement technology can obtain the flow velocity field data on the river surface, how to calculate the flow velocity and flow rate of the cross-section based on this is still a challenge in hydrological monitoring. Most of the existing methods for calculating the cross-sectional flow rate of a river channel are based on statistical analysis methods and use empirical formulas to calculate the flow rate of the entire river channel cross-section, such as the index velocity method. This method lacks the support of physical mechanisms, and its empirical coefficients lack applicability in different rivers, with disadvantages such as low calculation accuracy and poor universality. Moreover, according to the existing algorithms, the flow velocity field of the river cross-section cannot be effectively calculated. Therefore, there is still room for improvement in the existing calculation methods for river cross-section flow measurement, and the accuracy and applicability need to be further improved, and the content needs to be further improved.

[0005] Therefore, in order to overcome the deficiencies of traditional methods for calculating the flow rate of river channel cross-sections, there is an urgent need to provide a non-contact measurement and precise reconstruction calculation method for river channel flow fields, which can accurately determine the flow velocity field and flow rate of the river channel, greatly improve the measurement efficiency and accuracy, and effectively reduce the consumption of human and material resources. Summary of the Invention

[0006] The purpose of this application is to provide a method, device, medium and product for reconstructing the flow field of a river channel cross-section, which can accurately determine the flow velocity field and flow rate of the river channel, greatly improve the measurement efficiency and accuracy, and effectively reduce the consumption of human and material resources.

[0007] To achieve the above purpose, this application provides the following solutions: In the first aspect, this application provides a method for reconstructing the flow field of a river channel cross-section. The method for reconstructing the flow field of a river channel cross-section includes: Obtain the topographic data of the river channel cross-section; determine the three-dimensional cross-sectional topography and topographic measurement points of the river channel cross-section according to the topographic data of the river channel cross-section; and obtain the historical hydraulic parameters of the river reach at the topographic measurement points. The topographic data includes: measurement data of the riverbank surface topography and underwater topography obtained at a certain distance in the river channel cross-section, measurement point coordinates, and relative elevation data. The historical hydraulic parameters of the river reach include: hydraulic radius, maximum cross-sectional velocity, and average velocity of the river channel cross-section. According to the historical hydraulic parameters of the river reach, use the formula of entropy theory to determine the entropy parameters of the river channel cross-section. Use a non-contact measurement device to obtain the surface velocities at different positions in the river channel cross-section, and obtain the surface velocity time series data of the river channel cross-section. The non-contact measurement device includes: a radar speed measuring instrument or a large particle image velocimeter. According to the entropy parameters of the river channel cross-section and the surface velocity time series data of the river channel cross-section, use the formula of entropy theory velocity distribution, and use the particle swarm optimization algorithm to solve the equations to determine the longitudinal velocity of the river channel cross-section; and use the two-dimensional interp2 interpolation algorithm to obtain the flow velocity field data of the river channel cross-section. According to the flow velocity field data of the river channel cross-section, use the velocity-area method to determine the flow rate of the river channel cross-section.

[0008] Optionally, the obtaining of the topographic data of the river channel cross-section; determining the three-dimensional cross-sectional topography and topographic measurement points of the river channel cross-section according to the topographic data of the river channel cross-section specifically includes: Use an ultrasonic sounding instrument or an acoustic Doppler current profiler to measure the underwater topography at a certain distance in the river channel cross-section to obtain the measurement data of the underwater topography. Using a level and a rangefinder, along the cross-section direction of the river channel, with the relative elevation zero coordinate point, measure the relative elevation and distance of both sides of the riverbank until the fixed columns on both sides are reached, and obtain the measurement data of the surface topography of the riverbank; the relative elevation zero coordinate point is the fixed column on one side of the riverbank in the cross-section of the river channel. Use the relative elevation zero coordinate point to convert the relative elevation data, and determine the three-dimensional cross-section topography and topographic measurement points of the river channel cross-section based on the measurement data of the underwater topography and the surface topography of the riverbank.

[0009] Optionally, according to the historical hydraulic parameters of the river section, use the formula of entropy theory to determine the entropy parameter of the river channel cross-section, specifically including: If there are historical hydraulic parameters of the river section at the topographic measurement points, use the formula to determine the entropy parameter M; where Φ(M) is the entropy function, M is the entropy parameter, U m is the average velocity of the river channel cross-section, U max is the maximum velocity of the river channel cross-section. If there are no historical hydraulic parameters of the river section at the topographic measurement points, then according to the historical hydraulic parameters of the river section, use the formula to determine the entropy parameter M; where y max is the distance from the maximum velocity on the vertical line of the river channel cross-section to the bed surface, y0 is the reference plane where the assumed velocity is zero, k is the von Kármán parameter, R is the hydraulic radius, D is the flow depth, h is the maximum velocity on the vertical line of the river channel cross-section max from the water surface downward, and g is the acceleration due to gravity. max

[0010] Optionally, according to the entropy parameter of the river channel cross-section and the surface velocity time series data of the river channel cross-section, use the formula of entropy theory velocity distribution, and use the particle swarm optimization algorithm to solve the system of equations to determine the longitudinal velocity of the river channel cross-section; and use the two-dimensional interp2 interpolation algorithm to obtain the velocity field data of the river channel cross-section, specifically including: Use the formula to determine the velocity field data of the river channel cross-section at the topographic measurement point (x i , y) ; is the maximum velocity on the vertical line x i of the river channel cross-section, is the water depth at the vertical line x i of the river channel cross-section, M is the entropy parameter, is the distance from the maximum velocity on the vertical line x i of the river channel cross-section to the water surface, is the point position in the vertical direction, is the total number of vertical lines of the river channel cross-section; Use the formula Determine the vertical line x of the river channel cross-section i The maximum velocity of the vertical line ; is the surface velocity value at the vertical line x of the river channel cross-section i , is the downward shift value of the maximum velocity at the vertical line xi of the river channel cross-section is the water depth at the vertical line x of the river channel cross-section i ; Use the formula to determine the downward shift value of the maximum velocity on the vertical line x of the river channel cross-section i ; ; is the correction coefficient of the downward shift value of the maximum velocity on the vertical line x of the river channel cross-section i ; ; Use the formula of entropy theory as the constraint condition, and take the difference between the entropy parameter of the river channel cross-section and the theoretical entropy parameter of the river channel cross-section as the objective function value is the objective function to be optimized is the entropy parameter of the river channel cross-section is the theoretical entropy parameter of the river channel cross-section Use the particle swarm algorithm to solve the minimum value of the objective function value Use the formula to update the particle velocity is the i-th particle after the k-th update and are the positions of the i-th particle after the (k + 1)-th and k-th updates respectively is the inertia weight, which controls the ability of the particle to maintain the current flight direction. c1 and c2 are the cognitive constant and the social constant respectively. r1 and r2 are both random numbers, and their values are in the range of [0, 1]. P b is the historical optimal position of the particle, and G b is the global optimal position of the population Use the formula to perform two-dimensional interpolation on two-dimensional discrete data points; x i , y i are the coordinates of the known i-th two-dimensional discrete data point, and z i，j is the velocity value at the known two-dimensional discrete data point (x i , y i ); z i+1，j is the velocity value at (i + 1, j), z i，j+1 is the velocity value at (i, j + 1), z i+1，j+1 is the velocity value at (i + 1, j + 1); x and y are the coordinates of the two-dimensional discrete data point to be interpolated; z is the velocity of the point to be interpolated, x i+1, y i+1 is the coordinate of the known (i + 1)-th two-dimensional discrete data point; where i and j are the horizontal and vertical positions on the cross-section respectively.

[0011] Optionally, based on the velocity field data of the river channel cross-section, the velocity-area method is used to determine the flow rate of the river channel cross-section, specifically including: Determine the average velocity of the vertical line of the river channel cross-section at the topographic survey point according to the velocity field data of the river channel cross-section is the velocity at the vertical position 1 of the vertical line x of the river channel cross-section, V(x i ) i，j is the velocity at the vertical position j of the vertical line x of the river channel cross-section; i According to the average velocities V(x i ) of every two adjacent vertical lines x of the river channel cross-section i and the average velocity V(x i+1 ) between the vertical lines x of the river channel cross-section, determine the weighted average velocity V(xi) = [V(x i+1 ) + V(x i )] / 2 of the corresponding vertical lines of the river channel cross-section; i+1 Use the vertical lines of the river channel cross-section as the boundaries for dividing sub-regions, divide the open channel cross-section into several sub-regions, and determine the local area S i = ∑(b i +1 - b i )×(h i +1 - h i ) between the vertical lines of the river channel cross-section, where b i is the lateral sub-width between the vertical lines, and h i is the sub-depth in the vertical direction; According to the local area between the vertical lines of the river channel cross-section and the average velocity between the vertical lines of the river channel cross-section, use the velocity-area method to determine the flow rate of the river channel cross-section.

[0012] Optionally, according to the local area between the vertical lines of the river channel cross-section and the average velocity between the vertical lines of the river channel cross-section, using the velocity-area method to determine the flow rate of the river channel cross-section, specifically including: Use the formula Q = ∑S i × V (x i ) to determine the flow rate of the river channel cross-section Q ; where S i is the local area between the vertical lines, and V(x i ) is the average velocity between the vertical lines of the river channel cross-section.

[0013] In a second aspect, the present application provides a device for reconstructing the flow field of a river cross-section, the device for reconstructing the flow field of a river cross-section comprising: A data acquisition module, configured to acquire topographic data of a river cross-section; determine the three-dimensional cross-sectional topography of the river cross-section and topographic measurement points according to the topographic data of the river cross-section; and acquire historical hydraulic parameters of the river reach at the topographic measurement points; the topographic data includes: measurement data of the bank surface topography and underwater topography acquired at certain distances across the river cross-section, measurement point coordinates, and relative elevation data; the historical hydraulic parameters of the river reach include: hydraulic radius, maximum cross-sectional flow velocity, and average flow velocity of the river cross-section; An entropy parameter determination module, configured to determine the entropy parameter of the river cross-section according to the historical hydraulic parameters of the river reach by using the formula of entropy theory; A surface flow velocity determination module, configured to use a non-contact measurement device to acquire the surface flow velocities at different positions across the river cross-section, and obtain the surface flow velocity time series data of the river cross-section; the non-contact measurement device includes: a radar speed measurement instrument or a large particle image velocimeter; A flow velocity field data determination module, configured to determine the longitudinal flow velocity of the river cross-section according to the entropy parameter of the river cross-section and the surface flow velocity time series data of the river cross-section by using the formula of entropy theory for flow velocity distribution and solving the equations by using a particle swarm optimization algorithm; and obtain the flow velocity field data of the river cross-section by using a two-dimensional interp2 interpolation algorithm; A flow rate determination module for the river cross-section, configured to determine the flow rate of the river cross-section by using the velocity-area method according to the flow velocity field data of the river cross-section.

[0014] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the method for reconstructing the flow field of a river cross-section.

[0015] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for reconstructing the flow field of a river cross-section is implemented.

[0016] In a fifth aspect, the present application provides a computer program product, comprising a computer program, and when the computer program is executed by a processor, the method for reconstructing the flow field of a river cross-section is implemented.

[0017] According to the specific embodiments provided by the present application, the present application has the following technical effects: The present application provides a method, device, medium and product for reconstructing the cross-sectional flow field of a river channel. By using a non-contact measurement device to measure the surface velocity of the river channel cross-section, and applying a formula based on entropy theory, combined with the velocity-area method, the problems of accurately calculating the flow velocity field and flow rate of the river channel are solved, greatly improving the measurement efficiency and accuracy, and effectively reducing the consumption of human and material resources. This invention will help improve the comprehensive monitoring, intelligent perception and refined management capabilities of the basin, serve the construction of a digital twin basin, and provide more comprehensive, accurate, perceptible and intelligent information support for improving the management level of river basin governance; it has important practical value for real-time online monitoring of the river channel flow field under complex water conditions, and provides important support for strengthening water safety guarantee capabilities and water resources management. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 Schematic flow chart of a method for reconstructing the cross-sectional flow field of a river channel in an embodiment of the present application; Figure 2 Conceptual schematic diagram of a method for reconstructing the cross-sectional flow field of a river channel in an embodiment of the present application; Figure 3 Schematic diagram of the flow velocity field data measured by an acoustic Doppler current profiler (ADCP); Figure 4 Schematic diagram of the flow velocity field data calculated by the method based on entropy theory; Figure 5 Comparison diagram of the measured cross-sectional flow velocity field of the river channel and the calculated flow velocity field in the embodiment of the present application; Figure 6 Comparison diagram of the measured vertical flow velocity of the river channel and the calculated vertical flow velocity in the embodiment of the present application; Figure 7 Comparison diagram of the measured flow rate of each cross-section of this river channel and the calculated flow rate in the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present application belong to the scope of protection of the present application.

[0021] To make the above objects, features, and advantages of the present application more apparent and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] In an exemplary embodiment, as Figure 1 and Figure 2 shown, a method for reconstructing the flow field of a river channel cross-section is provided, and the method includes the following S101 to S104. Among them: S101, obtaining the terrain data of the river channel cross-section; determining the three-dimensional cross-sectional terrain of the river channel cross-section and the terrain measurement points according to the terrain data of the river channel cross-section; and obtaining the historical hydraulic parameters of the river reach at the terrain measurement points; the terrain data includes: the measurement data of the riverbank surface terrain and the underwater terrain obtained by taking measurements at certain distances across the river channel cross-section, the measuring point coordinates, and the relative elevation data; the historical hydraulic parameters of the river reach include: the hydraulic radius of the river channel cross-section, the maximum cross-sectional velocity, and the average velocity. S101 specifically includes: S11, using an ultrasonic sounder or an acoustic Doppler current profiler, etc., to measure the underwater terrain at certain distances across the river channel cross-section to obtain the measurement data of the underwater terrain. S12, using a level and a rangefinder, along the direction of the river channel cross-section, with the relative elevation zero coordinate point, measuring the relative elevation and distance of both riverbanks until the fixed columns on both banks are reached, to obtain the measurement data of the riverbank surface terrain; the relative elevation zero coordinate point is the fixed column on one side of the river channel cross-section. S13, converting the relative elevation data using the relative elevation zero coordinate point, and determining the three-dimensional cross-sectional terrain of the river channel cross-section and the terrain measurement points (X i , Y i , Z i ) according to the measurement data of the underwater terrain and the measurement data of the riverbank surface terrain.

[0023] S102, according to the historical hydraulic parameters of the river reach, using the formula of entropy theory to determine the entropy parameters of the river channel cross-section. According to whether the historical hydraulic parameters of the river reach exist at the terrain measurement points, the terrain measurement points are classified according to their attributes into measured stations and unmeasured stations; according to the soil quality of the river channel cross-section, it is divided into erodible river channels and non-erodible river channels, and the measurement cross-section is preliminarily divided according to the attributes.

[0024] S102 specifically includes: If the historical hydraulic parameters of the river reach exist at the terrain measurement points, then use the formula to determine the entropy parameter M; where Φ(M) is the entropy function, M is the entropy parameter, U m is the average cross-sectional velocity of the river channel, and U max is the maximum cross-sectional velocity on the vertical line of the river channel cross-section. If the historical hydraulic parameters of the river section do not exist at the topographic survey points, then through parameters such as the hydraulic radius of the river channel, use the formula to determine the entropy parameter M; where y max is the distance from the maximum flow velocity U on the vertical line of the river channel cross-section max to the bed surface, y0 is the reference surface where the assumed velocity is zero, k is the von Kármán parameter, R is the hydraulic radius, D is the flow depth, and h is the distance from the maximum flow velocity U on the vertical line of the river channel cross-section max downward from the water surface, and g is the acceleration due to gravity.

[0025] S103. Use non-contact measurement equipment to obtain the surface flow velocities at different positions of the river channel cross-section, and obtain the time-series data of the surface flow velocities of the river channel cross-section; considering the basic conditions of the river channel measurement section (such as air visibility, river particle composition, etc.), the difficulty of equipment layout in the measurement area, comprehensively select non-contact flow velocity measurement instruments such as radar velocity measurement instruments or particle image velocity measurement instruments for the non-contact measurement equipment; for the selection of non-contact measurement equipment, carry out the measurement of the river channel surface flow velocity and water level. Use an automatic control device to drive the radar velocity measurement instrument to measure the surface flow velocity and water level of the river channel at certain intervals, and record the position and flow velocity field data (X i , D i , U i ); S104. According to the entropy parameter of the river channel cross-section and the time-series data of the surface flow velocities of the river channel cross-section, use the formula of the entropy theory flow velocity distribution, and use the particle swarm optimization algorithm to solve the equations to determine the longitudinal flow velocity of the river channel cross-section; and use the two-dimensional interp2 interpolation algorithm to obtain the flow velocity field data of the river channel cross-section; S104 specifically includes: S41. According to the distance x i from the left bank of the vertical line of the river channel cross-section, considering the water depth at the location of this survey line, determine the basic value of the downward movement of the maximum flow velocity on this vertical line, and the formula is as follows: ; where δ(x i ) is the downward movement value of the maximum flow velocity at the location of the survey line, is the water depth at the vertical line x i of the river channel cross-section, is the vertical line x of the river channel cross-section i the correction coefficient of the downward movement value of the maximum flow velocity on.

[0026] S42. According to the flow velocity formula of the entropy theory, using the surface flow velocity, entropy parameter and downward movement value of the maximum flow velocity on the vertical line of the river channel cross-section as the basic data, obtain the maximum flow velocity of the vertical line: ; Among them, U surf (x i , D(x i )) is the surface flow velocity value at the measuring line of x i . is the maximum vertical flow velocity of the vertical line x i on the river cross-section.

[0027] S43, using the formula of entropy theory as the constraint condition, and taking the difference between the entropy parameter of the river cross-section and the theoretical entropy parameter of the river cross-section as the objective function value; is the objective function to be optimized, is the entropy parameter of the river cross-section, is the theoretical entropy parameter of the river cross-section; Using the particle swarm algorithm to solve the minimum value of the objective function value; Using the formula to update the particle velocity; is the i-th particle after the k-th update, and are the positions of the i-th particle after the (k + 1)-th and k-th updates respectively, is the inertia weight, which controls the ability of the particle to maintain the current flight direction. c1 and c2 are the cognitive constant and the social constant respectively. r1 and r2 are both random numbers, taking values in [0, 1]. P b is the historical optimal position of the particle, and G b is the global optimal position of the population; Using the formula to perform two-dimensional interpolation on two-dimensional discrete data points; x i , y i are the coordinates of the known i-th two-dimensional discrete data point, and z i，j is the flow velocity value at the known two-dimensional discrete data point (x i , y i ); z i+1，j is the flow velocity value at (i + 1, j), z i，j+1 is the flow velocity value at (i, j + 1), and z i+1，j+1 is the flow velocity value at (i + 1, j + 1); x and y are the coordinates of the two-dimensional discrete data point to be interpolated; z is the flow velocity at the point to be interpolated, and x i+1 , y i+1 are the coordinates of the known (i + 1)-th two-dimensional discrete data point; where i and j are the horizontal and vertical positions on the cross-section respectively.

[0028] S44. Substitute data such as the entropy parameter, the maximum vertical velocity, and the downstream shift value of the maximum velocity into the river channel velocity calculation formula. Through the particle swarm optimization solution loop process in S43, obtain the point velocity value at the position (x, y), that is, obtain the velocity field data of the river channel cross-section: ; Among them, is the water depth at the vertical line x of the river channel cross-section, M is the entropy parameter, i is the distance of the maximum velocity from the water surface at the vertical line x of the river channel cross-section, is the vertical position on the vertical line x of the river channel cross-section, i is the distance of the maximum velocity from the water surface at the vertical line x of the river channel cross-section, is the vertical position, is the total number of vertical lines of the river channel cross-section.

[0029] S105. According to the velocity field data of the river channel cross-section, use the velocity-area method to determine the flow rate of the river channel cross-section.

[0030] S105 specifically includes: S51. Determine the average velocity of the vertical lines of the river channel cross-section at the topographic survey points according to the velocity field data of the river channel cross-section; Determine the average velocity of the vertical lines of the river channel cross-section at the topographic survey points according to the velocity field data of the river channel cross-section is the velocity at the vertical position 1 of the vertical line x of the river channel cross-section, V(x i ) is the velocity at the vertical position j of the vertical line x of the river channel cross-section. i，j is the velocity at the vertical position 1 of the vertical line x of the river channel cross-section, V(x i ) is the velocity at the vertical position j of the vertical line x of the river channel cross-section.

[0031] S52. According to the average velocities V(x i ) of every two adjacent vertical lines x of the river channel cross-section and the average velocity V(x i ) between the vertical lines x of the river channel cross-section, determine the weighted average velocity V(xi) = [V(x i+1 ) + V(x i+1 )] / 2 of the river channel cross-section corresponding to the vertical lines of the river channel cross-section; i ) + V(x i+1 )] / 2; S53. Use the vertical lines of the river channel cross-section as the boundaries for dividing sub-regions, divide the open channel cross-section into several sub-regions, and determine the local area S i = ∑(b i +1 - b i ) × (h i +1 - h i ), where b i is the transverse sub-width between vertical lines, h i is the sub-depth in the vertical direction; S54. Based on the local area between the vertical lines of the river cross-section and the average flow velocity between the vertical lines of the river cross-section, the velocity-area method is used to determine the flow rate of the river cross-section. That is, according to the principle of calculating the natural river flow rate in hydraulics, the velocity-area method is used. This method first uses the velocity-measuring vertical lines as the boundaries for dividing sub-regions, divides the open-channel cross-section into several sub-regions, then calculates the cross-sectional area, average flow velocity and flow rate of each sub-region based on the measured flow velocity and water depth, and finally sums up the flow rates of each sub-region to obtain the result.

[0032] Using the formula Q =∑S i × V (x i ) to determine the flow rate of the river cross-section Q ; The present application has the following effects: (1) The present application provides a non-contact measurement and precise reconstruction calculation method for the river flow field, mainly aiming to solve the problems of difficult measurement, high cost, poor accuracy and difficulty in real-time online monitoring of the river cross-section flow rate. The method described in the present application has high accuracy for the flow field reconstruction calculation of natural rivers, is applicable to different river types of large rivers, medium-sized and small rivers, and can realize the synchronous monitoring of the flow velocity field and flow rate in real-time online; (2) The method provided by the present application has a theoretical basis in hydraulics and probability theory, etc. It can accurately identify the flow velocity distribution of each vertical line of the river through surface flow velocity measurement and adaptive adjustment of entropy parameters, and is effectively applicable to different river types and river reaches. Compared with traditional calculation methods, it has more physical mechanisms, strong interpretability, convenient application, wide applicability, and high accuracy and reliability of calculation; (3) The method provided by the present application is based on non-contact measurement of the river, and has the advantages of high automation, strong adaptability to complex environments, high measurement safety, etc., avoiding potential safety hazards to hydrological measurement personnel. At the same time, it makes full use of surface flow velocity field data, is applicable to the whole river, and is applied to different river types and river reaches. Compared with traditional calculation methods, it has hydraulics and river dynamics mechanisms, convenient application, wide applicability, and high accuracy and reliability of calculation; (4) The method provided by the present application can perform flow field calculations of multiple cross-sections and flow field modeling of the whole river reach. It makes full use of real-time data such as the topography of the river cross-section and the measured surface flow velocity, calculates the flow velocity field of each cross-section of the on-site river through the method provided by the present application, and reconstructs the flow field of the whole river reach by interpolation and fitting through computer software. It has high calculation efficiency, can accurately depict the flow velocity distribution of the river channel, and can describe the hydrological conditions of the river channel in real-time, greatly improving the measurement accuracy of the river cross-section flow rate.

[0033] (5) The method provided by this application can not only obtain the flow rate of the river channel cross-section, but also reconstruct the velocity field of the entire river channel cross-section, which solves the problems of difficult measurement of underwater velocity and shortage of continuous data in natural rivers. And it can provide more comprehensive data support for understanding river hydrodynamics. At the same time, the real-time monitoring of the full-section velocity field helps to identify adverse flow patterns in a timely manner, evaluate their impacts on river channel evolution, etc., and provide data support for decision-making such as water resource management and river channel governance; (6) The precise calculation method provided by this application has strong operability. It can be written into a program, with portability and nesting. As long as the cross-section topography of the measured river channel and the data of the measured river channel cross-section velocity field are used as input data, the automatic and rapid precise calculation of the river channel cross-section flow field can be realized through the built-in model algorithm of this application, and the real-time online full-section velocity and river channel flow rate can be output. It provides technical support for river intelligent perception and basin comprehensive detection, and also helps to improve the river fine control ability and basin governance and management ability level.

[0034] The following is illustrated by specific embodiments. The research reach of this embodiment belongs to a wide and shallow reach, with a straight river channel and a stable riverbed. The surface velocity and water level of the river channel cross-section are obtained through an automatic control device and a radar flow measurement device; a moving Doppler profiler is used to measure basic data such as cross-section velocity, flow rate (used for verification), and water depth along the river channel cross-section; computer software is used to fit the cross-section topography of the river channel with the abscissa as the variable; considering large rivers, the interval of each section of the river channel width is set to 1.0 m. The attributes of the measurement section are divided into measurement stations with data and erodible soil river channels. The theoretical entropy function value can be calculated through the maximum velocity and average velocity formulas of the cross-section, and the value is 0.591. Combining the on-site situation, a radar velocity measurement instrument is comprehensively selected as a non-contact measurement device to obtain the surface velocity and water level of the river channel cross-section. Through the entropy theory formula model and the surface velocity field data, the point velocity values of the full cross-section are calculated by using the operation of the computer particle swarm algorithm. Then, through the hydraulics natural river channel flow calculation method, the flow rate of the entire cross-section is obtained. Figure 3 is the velocity field data measured by ADCP, Figure 4 is the velocity field data calculated based on the entropy theory method, Figure 5 is the comparison between the measured cross-section velocity field of the river channel and the calculated velocity field of the embodiment of this application. As Figures 3 - 5 shown, the average relative error between the calculated velocity field and the measured velocity field of the full cross-section is 12.50%. To further verify the accuracy of the present invention, the measured velocity vertical distribution on the cross-section is compared and analyzed with the calculated velocity vertical distribution. The result is as Figure 6 . The measured cross-section flow rate is compared and analyzed with the calculated flow rate. The calculated river channel cross-section flow rate is 150642 m 3 / s, and the measured river channel cross-section flow rate is 154474 m 3 / s, and the relative error is only 2.48%; to further verify the beneficial effects of this application, the measured flow rates and calculated flow rates of each cross-section in the study area were compared and analyzed. During the high flood flow period, the maximum relative error of the flow rate was only 1.36%, and the error of each cross-section was within 10%. The comparison between the measured flow rate and the calculated flow rate of each cross-section is shown in Figure 7 .

[0035] Based on the same inventive concept, the embodiment of this application also provides a river cross-section flow field reconstruction device for implementing the river cross-section flow field reconstruction method involved above. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the river cross-section flow field reconstruction device provided below can refer to the limitations on the river cross-section flow field reconstruction method in the above text, and will not be repeated here.

[0036] In an exemplary embodiment, a river cross-section flow field reconstruction device is provided, including: A data acquisition module, configured to acquire the terrain data of the river cross-section; determine the three-dimensional cross-section terrain and terrain measurement points of the river cross-section according to the terrain data of the river cross-section; and acquire the historical hydraulic parameters of the river reach at the terrain measurement points; the terrain data includes: the measurement data of the bank surface terrain and underwater terrain obtained at a certain distance in the river cross-section, the measuring point coordinates, and the relative elevation data; the historical hydraulic parameters of the river reach include: the hydraulic radius, the maximum cross-section velocity, and the average velocity of the river cross-section; An entropy parameter determination module, configured to determine the entropy parameter of the river cross-section according to the historical hydraulic parameters of the river reach by using the formula of entropy theory; A surface velocity determination module, configured to use a non-contact measurement device to acquire the surface velocities at different positions in the river cross-section to obtain the surface velocity time series data of the river cross-section; the non-contact measurement device includes: a radar speed measurement instrument or a large particle image velocimeter; A flow velocity field data determination module, configured to determine the longitudinal flow velocity of the river cross-section according to the entropy parameter of the river cross-section and the surface velocity time series data of the river cross-section by using the formula of entropy theory flow velocity distribution, and use the two-dimensional interp2 interpolation algorithm to obtain the flow velocity field data of the river cross-section; A flow rate determination module for the river cross-section, configured to determine the flow rate of the river cross-section according to the flow velocity field data of the river cross-section by using the velocity-area method.

[0037] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store video tag processing data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. The computer program, when executed by the processor, implements a video tag processing method.

[0038] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which, when executed by a processor, implements the steps in the above method embodiments.

[0039] In an exemplary embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps in the above method embodiments.

[0040] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0041] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0042] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0043] In the present application, all actions of obtaining signals, information, or data are carried out on the premise of complying with the corresponding data protection regulations and policies of the country where the location is located and obtaining the authorization given by the owner of the corresponding device.

[0044] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0045] In this article, specific examples are used to illustrate the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for reconstructing the flow field of a river cross-section, characterized in that The method for reconstructing the flow field of the river channel cross-section includes: Obtaining the topographic data of the river channel cross-section; determining the three-dimensional cross-sectional topography of the river channel cross-section and the topographic measurement points according to the topographic data of the river channel cross-section; and obtaining the historical hydraulic parameters of the river reach at the topographic measurement points; the topographic data includes: the measurement data of the bank surface topography and the underwater topography obtained at certain distances in the river channel cross-section, the measuring point coordinates, and the relative elevation data; the historical hydraulic parameters of the river reach include: the hydraulic radius, the maximum cross-sectional velocity, and the average velocity of the river channel cross-section; Determining the entropy parameter of the river channel cross-section according to the historical hydraulic parameters of the river reach by using the formula of entropy theory; Using a non-contact measurement device to obtain the surface velocities at different positions in the river channel cross-section, and obtaining the surface velocity time series data of the river channel cross-section; the non-contact measurement device includes: a radar speed measuring instrument or a large particle image velocimeter; According to the entropy parameter of the river channel cross-section and the surface velocity time series data of the river channel cross-section, using the formula of entropy theory velocity distribution, and using the particle swarm optimization algorithm to solve the equations to determine the longitudinal velocity of the river channel cross-section; and using the two-dimensional interp2 interpolation algorithm to obtain the flow velocity field data of the river channel cross-section; Determining the flow rate of the river channel cross-section according to the flow velocity field data of the river channel cross-section by using the velocity-area method.

2. The method for reconstructing the flow field of a river channel cross-section according to claim 1, characterized in that, The obtaining of the topographic data of the river channel cross-section; determining the three-dimensional cross-sectional topography of the river channel cross-section and the topographic measurement points according to the topographic data of the river channel cross-section specifically includes: Using an ultrasonic sounder or an acoustic Doppler current profiler to measure the underwater topography at certain distances in the river channel cross-section to obtain the measurement data of the underwater topography; Using a level and a rangefinder to measure the relative elevation and distance of both banks along the direction of the river channel cross-section with the relative elevation zero coordinate point until the fixed columns on both banks are reached, to obtain the measurement data of the bank surface topography; the relative elevation zero coordinate point is the fixed column on one bank of the river channel cross-section; Converting the relative elevation data by using the relative elevation zero coordinate point, and determining the three-dimensional cross-sectional topography of the river channel cross-section and the topographic measurement points according to the measurement data of the underwater topography and the measurement data of the bank surface topography.

3. The method for reconstructing the cross-sectional flow field of a river channel according to claim 1, wherein The determining of the entropy parameter of the river channel cross-section according to the historical hydraulic parameters of the river reach by using the formula of entropy theory specifically includes: If the historical hydraulic parameters of a river section exist at the topographic survey points, the formula is used to determine the entropy parameter M; where Φ(M) is the entropy function, M is the entropy parameter, and U m is the average cross-sectional velocity of the river channel, U max is the maximum cross-sectional velocity of the river channel, and e is the natural logarithm; If the historical hydraulic parameters of the river section do not exist for the topographic survey points, then according to the historical hydraulic parameters of the river section, use the formula to determine the entropy parameter M; where y max is the distance from the maximum flow velocity U max on the vertical line of the river cross-section to the bed surface, y0 is the reference plane where the assumed velocity is zero, k is the von Kármán parameter, R is the hydraulic radius, D is the flow depth, and h is the distance from the maximum flow velocity U max from the water surface downwards, and g is the acceleration due to gravity.

4. The method for reconstructing the cross-sectional flow field of a river channel according to claim 1, characterized in that The determining of the longitudinal velocity of the river channel cross-section according to the entropy parameter of the river channel cross-section and the surface velocity time series data of the river channel cross-section by using the formula of entropy theory velocity distribution, and using the particle swarm optimization algorithm to solve the equations, and using the two-dimensional interp2 interpolation algorithm to obtain the flow velocity field data of the river channel cross-section specifically includes: Using the formula to determine the velocity field data of the river channel cross-section at the topographic survey point (x i , y); ; is the maximum vertical velocity of the vertical line x i on the river channel cross-section, is the water depth at the vertical line x i of the river channel cross-section, M is the entropy parameter, is the distance from the maximum velocity on the vertical line x i of the river channel cross-section to the water surface, is the point position in the vertical direction, is the total number of vertical lines of the river channel cross-section; Using the formula to determine the vertical line x of the river channel cross-section i and the maximum velocity of the vertical line ; where i is the surface velocity value at the vertical line x of the river channel cross-section, is the downward shift value of the maximum velocity at the vertical line xi of the river channel cross-section, and i is the water depth at the vertical line x of the river channel cross-section; Using the formula to determine the downstream displacement value of the maximum velocity at the vertical line x of the river channel cross-section i ; ; is the downstream displacement value of the maximum velocity at the vertical line x of the river channel cross-section i ; is the correction coefficient of Using the formula of entropy theory as a constraint condition, the difference between the entropy parameter of the river channel cross-section and the theoretical entropy parameter of the river channel cross-section is used as the objective function value; is the objective function to be optimized, is the entropy parameter of the river channel cross-section, is the theoretical entropy parameter of the river channel cross-section; Using the particle swarm algorithm to solve the minimum value of the objective function value; Update the particle velocity using the formula ; is the i-th particle after the k-th update, and are the positions of the i-th particle after the (k + 1)-th and k-th updates respectively, is the inertia weight, which controls the ability of the particle to maintain its current flight direction. c1 and c2 are the cognitive constant and social constant respectively, and r1, r2 are both random numbers with values in the range [0, 1]. P b is the historical best position of the particle, and G b is the global best position of the population; Using the formula perform two-dimensional interpolation on two-dimensional discrete data points; x i , y i are the coordinates of the i-th known two-dimensional discrete data point, and z i，j is the flow velocity value at the known two-dimensional discrete data point (x i , y i ); z i+1，j is the flow velocity value at (i + 1, j), z i，j+1 is the flow velocity value at (i, j + 1), z i+1，j+1 is the flow velocity value at (i + 1, j + 1); x and y are the coordinates of the two-dimensional discrete data point to be interpolated; z is the flow velocity at the point to be interpolated, x i+1 , y i+1 are the coordinates of the (i + 1)-th known two-dimensional discrete data point; where i and j are the horizontal and vertical positions on the cross-section respectively.

5. The method for reconstructing the cross-sectional flow field of a river channel according to claim 1, characterized in that The determining of the flow rate of the river channel cross-section according to the flow velocity field data of the river channel cross-section by using the velocity-area method specifically includes: Determine the average velocity of the vertical line of the river channel cross-section at the topographic survey point according to the velocity field data of the river channel cross-section For the vertical line x of the river channel cross-section i The velocity at the vertical position 1 at x is V(x i，j ) is the velocity at the vertical position j at the vertical line x of the river channel cross-section i ; According to the vertical line x between each two adjacent river cross sections i The average flow velocity V(x i ) and the vertical line x of the river cross section i+1 The average flow rate V(x i+1 ) Determine the weighted average velocity V(xi)=[V(x i )+V(x i+1 )] / 2; Taking the vertical lines of the river cross-section as the boundaries for dividing sub-regions, the open channel cross-section is divided into several sub-regions, and the area S of the local region between the vertical lines of the river cross-section is determined i =∑(b i +1 - b i )×(h i +1 - h i ), where b i is the lateral sub-width between the vertical lines, and h i is the sub-depth in the vertical direction; Determining the flow rate of the river channel cross-section according to the local area between the vertical lines of the river channel cross-section and the average velocity between the vertical lines of the river channel cross-section by using the velocity-area method.

6. The method for reconstructing the cross-sectional flow field of a river channel according to claim 5, characterized in that The determining of the flow rate of the river channel cross-section according to the local area between the vertical lines of the river channel cross-section and the average velocity between the vertical lines of the river channel cross-section by using the velocity-area method specifically includes: Using the formula Q =∑S i × V (x i ) to determine the flow rate of the river cross-section Q ; Among them, S i is the area of the local region between perpendiculars, and V(x i ) is the average velocity between perpendiculars of the river cross-section.

7. A cross-sectional flow field reconstruction device for a river channel, characterized in that, The cross-sectional flow field reconstruction device for a river channel includes: A data acquisition module, which is used to acquire the topographic data of the river channel cross-section; determine the three-dimensional cross-sectional topography of the river channel cross-section and the topographic measurement points according to the topographic data of the river channel cross-section; and acquire the historical hydraulic parameters of the river section at the topographic measurement points; the topographic data includes: the measurement data of the riverbank surface topography and the underwater topography obtained at a certain distance along the river channel cross-section, the measuring point coordinates, and the relative elevation data; the historical hydraulic parameters of the river section include: the hydraulic radius of the river channel cross-section, the maximum cross-sectional velocity, and the average velocity. An entropy parameter determination module, which is used to determine the entropy parameters of the river channel cross-section according to the historical hydraulic parameters of the river section and the formula of entropy theory. A surface velocity determination module, which is used to use a non-contact measurement device to acquire the surface velocities at different positions in the river channel cross-section and obtain the surface velocity time series data of the river channel cross-section; the non-contact measurement device includes: a radar speed measuring instrument or a large particle image velocimeter. A flow velocity field data determination module, which is used to determine the longitudinal flow velocity of the river channel cross-section according to the entropy parameters of the river channel cross-section and the surface velocity time series data of the river channel cross-section, use the formula of entropy theory flow velocity distribution, and solve the equations by using the particle swarm optimization algorithm; and use the two-dimensional interp2 interpolation algorithm to obtain the flow velocity field data of the river channel cross-section. A flow rate determination module for the river channel cross-section, which is used to determine the flow rate of the river channel cross-section according to the flow velocity field data of the river channel cross-section by using the velocity-area method.

8. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the cross-sectional flow field reconstruction method for a river channel according to any one of claims 1-6.

9. 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 cross-sectional flow field reconstruction method for a river channel according to any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the cross-sectional flow field reconstruction method for a river channel according to any one of claims 1-6.

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