Automatic flow measurement method and system for straight opening section of trunk canal

Abstract

The invention discloses an automatic flow measurement method and system for a straight opening section of a trunk canal, and belongs to the field of big data analysis and mining, and the method comprises the following steps: constructing a uniformity index, and selecting a flow velocity calculation method according to an index value; monitoring the sand content dynamic correction roughness in real time, and iteratively calculating the correction flow velocity; the method comprises the following steps of: calculating initial flow rate according to a corrected flow rate and a real-time section area by combining and analyzing a spiral flow risk, checking and verifying, correcting an influence value by superposing a spiral flow correction coefficient, and outputting final corrected flow rate. High precision and intelligentization of main canal flow velocity and flow measurement are achieved, spiral flow parameters are associated with a first factor of uniformity, spiral flow risks are judged through double standards, possible deviation caused by single parameter judgment is reduced, meanwhile, manual intervention is reduced, flow measurement efficiency and stability are improved, and a solid foundation is laid for subsequent analysis and system optimization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of big data analysis and mining, in particular to an automatic flow measurement method and system for a straight opening section of a trunk canal. BACKGROUND

[0002] With the acceleration of digital transformation of water conservancy, an efficient, fully automatic and highly robust flow measurement system will gradually cover all rivers and streams, for example, a Doppler ultrasonic open channel flowmeter measures the open channel flow velocity using the Doppler effect, transmits ultrasonic waves of a specific frequency to the water flow through a sensor, when the ultrasonic waves encounter moving particles or bubbles in the water, the frequency of the reflected waves will shift, that is, the Doppler shift, which is proportional to the flow velocity. The instrument can obtain the flow velocity of the measurement point by calculating the frequency shift value, and then calculate the flow rate according to the velocity-area method by combining the open channel section area.

[0003] For example, the Chinese invention patent with publication number CN118052680A discloses an ecological flow detection method for a tidal section of a river flowing into the sea, which includes: obtaining basin characteristic data; determining a section ecological flow control index according to the basin characteristic data; obtaining information of a hydrological station and measured runoff data; determining a section daily net discharge according to the information of the hydrological station and the measured runoff data; and calculating the section ecological flow according to the section ecological flow control index and the section daily net discharge.

[0004] For example, the Chinese invention patent with publication number CN113962822B discloses a single-trunk canal optimal water distribution method based on a dynamic programming method, which includes: establishing a target function with the minimum sum of water shortage quantities of controlled water receiving areas of each branch canal of a single-trunk canal in a single irrigation period as the target; setting constraint conditions; and model solving: (a) determining the positions and numbers of branch canal head control gates controlled by the single-trunk canal, and determining the water requirements of crops in the controlled water receiving areas of each branch canal in the irrigation period; (b) taking the position numbers of the branch canal head control gates as stages and the total water distribution quantities of the branch canal head control gates as state variables, constructing a state transition equation, and determining benefit and cost functions of each stage; and (c) obtaining optimal water distribution quantities of the branch canal head control gates that meet the minimum sum of water shortage quantities of the controlled areas of each branch canal by using a sequential recursion method.

[0005] The above-mentioned technology at least has the following technical problems: The wide and shallow section of the trunk canal causes uneven lateral distribution of flow velocity, forming non-uniform flow, and strong non-uniform flow in the wide and shallow channel can form secondary flow or even spiral flow, which causes a large amount of water flow to concentrate on the concave bank surface layer, while the convex bank bottom layer has very low flow velocity, the section velocity measurement point overestimates the local flow velocity, resulting in total flow calculation error. SUMMARY

[0006] In one aspect, the embodiment of the present application provides an automatic flow measurement method for a straight opening section of a dry canal, which comprises the following steps. The flow uniformity parameters of the straight opening section of the dry canal are collected, the flow uniformity indexes of the straight opening section of the dry canal are analyzed, and thus the flow velocity measurement strategy is determined.

[0007] When the flow velocity measurement strategy is hydraulic slope integral correction, the flow super parameters of the straight opening section of the dry canal are collected in real time, the hydraulic slope of the straight opening section of the dry canal is obtained, the flow velocity of the straight opening section of the dry canal is inversely deduced, and then iterative optimization is performed.

[0008] The flow velocity direction angle of the straight opening section of the dry canal is analyzed, the flow calculation strategy of the straight opening section of the dry canal is determined in combination with the first factor of the uniformity, and when the flow calculation strategy of the straight opening section of the dry canal is spiral correction, spiral flow correction analysis is performed.

[0009] The flow velocity verification of the straight opening section of the dry canal is performed, the flow velocity verification strategy is determined, and when the flow velocity verification strategy is hydraulic slope correction, the flow velocity calculation of the straight opening section of the dry canal is performed again.

[0010] In another aspect, the embodiment of the present application provides an automatic flow measurement system for a straight opening section of a dry canal, which comprises the following modules.

[0011] The flow velocity correction module collects the parameters of the straight opening section of the dry canal in real time when the flow velocity measurement strategy is hydraulic slope integral correction, obtains the hydraulic slope of the straight opening section of the dry canal, inversely deduces the flow velocity of the straight opening section of the dry canal, and then performs iterative optimization.

[0012] The spiral flow correction module analyzes the flow velocity direction angle of the straight opening section of the dry canal, determines the flow calculation strategy of the straight opening section of the dry canal in combination with the first factor of the uniformity, and performs spiral flow correction analysis when the flow calculation strategy of the straight opening section of the dry canal is spiral correction.

[0013] The flow velocity verification module performs the flow velocity verification of the straight opening section of the dry canal, determines the flow velocity verification strategy, and performs the flow velocity calculation of the straight opening section of the dry canal again when the flow velocity verification strategy is hydraulic slope correction.

[0014] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects. 1、The present application realizes high precision and intelligentization of dry canal flow velocity and flow measurement through multi-dimensional parameter monitoring, dynamic correction mechanism and full-process data verification, which can accurately adapt to different water flow uniformity scenarios, effectively cope with complex water flow environment such as high sediment content and spiral flow, improve measurement adaptability through parameter linkage, form a complete data closed loop, provide reliable basis for irrigation scheduling and channel maintenance, correlate spiral flow parameters with the first factor of uniformity, judge spiral flow risk by double standards of direction angle deviation and the first factor of uniformity, trigger measurement error or local disturbance review under critical state, make dynamic adjustment of spiral flow correction coefficient more in line with actual flow state, reduce the deviation that may occur in single parameter judgment, reduce manual intervention, improve flow measurement efficiency and stability, and ensure data traceability, laying a solid foundation for subsequent analysis and system optimization.

[0015] 2、The present application can scientifically reflect the actual distribution of cross section flow velocity through comprehensive and accurate evaluation of water flow uniformity, collection of various parameters and comprehensive derivation of uniformity index. Based on the interval of water flow uniformity index, the corresponding flow velocity measurement method is determined, the differentiated selection of measurement strategy is realized, and the limitation of single method under different uniformity states is avoided, laying a reasonable and efficient foundation for subsequent flow velocity measurement.

[0016] 3、The present application ensures the timeliness and accuracy of parameters by real-time acquisition of various cross section parameters and combination of sediment content monitoring for roughness correction. Through hydraulic slope correction of upstream and downstream auxiliary sections and error-based iterative optimization process, the real flow velocity can be continuously approached, and the measurement error can be effectively reduced. When multiple iterations do not converge, an alarm is triggered, and flow state abnormalities can be detected in time, ensuring the reliability of flow velocity measurement.

[0017] 4、The present application calculates the velocity direction angle by collecting spiral flow parameters, accurately judges the spiral flow risk level in combination with the first factor of uniformity, and then determines whether to introduce correction coefficient or perform error review. This multi-parameter based flow state analysis can effectively cope with the influence of spiral flow and other complex flow states on flow velocity measurement, further improving the effectiveness of flow velocity data. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is an automatic flow measurement method flow chart of a straight opening cross section of a dry canal provided by the embodiment of the present application; Figure 2A structure schematic diagram of an automatic flow measurement system of a dry canal straight opening section provided by the embodiment of the present application; Figure 3 An execution strategy diagram of an automatic flow measurement method of a dry canal straight opening section provided by the embodiment of the present application; Figure 4 A mind map of an automatic flow measurement system of a dry canal straight opening section provided by the embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the present application will be described below with reference to the drawings.

[0021] In the embodiments of the present application, the words such as "example", "for example" and the like are used to represent as an example, illustration or description. Any embodiment or design scheme described as "example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. In fact, the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present application, the meaning expressed by "and / or" can be both, or can be one of the two.

[0022] In the embodiments of the present application, "image" and "picture" can be used interchangeably at times. It should be pointed out that when the distinction is not emphasized, the meanings expressed are consistent. "Of", "corresponding" and "corresponding" can be used interchangeably at times. It should be pointed out that when the distinction is not emphasized, the meanings expressed are consistent.

[0023] In the embodiments of the present application, sometimes the subscript such as W1 can be written in the form of non-subscript such as W1. When the distinction is not emphasized, the meanings expressed are consistent.

[0024] In order to make the technical problems, technical solutions and advantages to be solved by the present application more clear, specific embodiments will be described in detail below with reference to the drawings.

[0025] Referring to Figure 1 The flow chart of the automatic flow measurement method of the dry canal straight opening section shown in the figure, first, the uniformity index is constructed, and the flow velocity calculation method is selected according to the index value; second, the sediment concentration is monitored in real time, and the roughness is corrected, the auxiliary section spacing is determined based on the uniformity, and the flow velocity is corrected by the upstream and downstream water head difference iteration; then, the spiral flow risk is analyzed by combining the first factor of uniformity and three-dimensional flow velocity, and the spiral flow correction coefficient is dynamically introduced; finally, after comparison and historical curve verification of the upstream and downstream sections, the initial flow is calculated by the corrected flow velocity and real-time section area, and the spiral flow correction coefficient and sediment concentration correction influence value are superimposed, and the final corrected flow is output. The processing flow of the method can include the following steps: For example,Figure 3 The diagram shows the execution strategy of an automatic flow measurement method for a straight-opening section of a dry canal provided by an embodiment of the present invention. By constructing a flow uniformity index, selecting a flow velocity calculation method based on the flow uniformity index, and performing hydraulic gradient integral correction, the spacing between auxiliary sections is determined based on the flow uniformity index, and the flow velocity is corrected by iterative calculation of the upstream and downstream head difference.

[0026] Collect the flow uniformity parameters of the straight opening section of the main canal, analyze the flow uniformity index of the straight opening section of the main canal, and thus determine the flow velocity measurement strategy.

[0027] Furthermore, the uniformity of water flow in the straight-opening section of the main canal was analyzed. The specific analysis method is as follows: Collect parameters of water flow uniformity at the cross-section of the main canal, including lateral standard deviation, vertical gradient, and fluctuation coefficient of variation.

[0028] Analysis of the flow uniformity index of the straight opening section of the main canal based on the flow uniformity parameters of the main canal cross section.

[0029] The lateral standard deviation reflects the dispersion of flow velocity in the horizontal direction. The larger the value, the more significant the difference in flow velocity at different lateral positions of the cross section, and the more uneven the distribution of flow velocity in the horizontal direction, which in turn leads to a lower flow uniformity index. The vertical gradient is a representation of the rate of change of vertical flow velocity. The larger the value, the more drastic the change of flow velocity in the vertical direction, and the more uneven the distribution of flow velocity between upper and lower layers, which also reduces the flow uniformity index. The fluctuation coefficient of variation comprehensively reflects the relative fluctuation of flow velocity in the cross section. The larger the value, the more obvious the fluctuation of flow velocity over time, the worse the flow velocity stability, and the lower the flow uniformity index.

[0030] When the lateral standard deviation increases, indicating uneven distribution of horizontal velocity, local circulation is triggered, which in turn leads to changes in the vertical velocity distribution, increasing the vertical gradient. A large vertical gradient means drastic changes in vertical velocity, active energy exchange between the upper and lower layers of the flow, and easy to cause temporal fluctuations in velocity, resulting in an increased coefficient of variation of the fluctuation. A large lateral standard deviation indicates uneven distribution of horizontal velocity, which may lead to intensified internal interactions within the flow, increasing the temporal fluctuations in velocity, i.e., increasing the coefficient of variation of the fluctuation.

[0031] The lateral standard deviation is calculated by simultaneously collecting flow velocity data at multiple lateral measuring points (such as left, middle, and right positions) along the cross-section of the main canal. After obtaining the flow velocity values ​​at each measuring point, the standard deviation is calculated using the standard deviation formula. Data collection can be accomplished by deploying multiple flow meters along the cross-section or by using a mobile flow meter. The vertical gradient can be calculated by collecting flow velocity data of multiple measuring points at the same vertical position of the section along the water depth direction, and according to the ratio of the flow velocity difference of adjacent measuring points to the water depth difference. The vertical flow velocity variation rate, i.e. the vertical gradient, is calculated. Usually, an instrument capable of measuring flow velocity at different water depths, such as a direct-reading flowmeter, is used for layered measurement. The fluctuation coefficient of variation is calculated by collecting flow velocity data for a period of time through continuous monitoring of a fixed measuring point of the section by a flowmeter, calculating the standard deviation and average value of the flow velocity in the period of time, and then calculating the fluctuation coefficient of variation according to the formula: fluctuation coefficient of variation = (standard deviation / average value) x 100%. The data can be obtained by fixing the flowmeter at a certain position for continuous monitoring.

[0032] The preset lateral standard deviation coefficient distribution factor, vertical gradient coefficient distribution factor and fluctuation coefficient of variation coefficient distribution factor in the database are extracted.

[0033] It should be noted that the value range of the lateral standard deviation coefficient distribution factor, the vertical gradient coefficient distribution factor and the fluctuation coefficient of variation coefficient distribution factor is 0 to 1, and the sum of the lateral standard deviation coefficient distribution factor, the vertical gradient coefficient distribution factor and the fluctuation coefficient of variation coefficient distribution factor is 1. When used, the preset values can be directly extracted from the database. For example, a one-to-one mapping set is constructed by mapping the lateral standard deviation, vertical gradient and fluctuation coefficient of variation to the corresponding lateral standard deviation coefficient distribution factor, vertical gradient coefficient distribution factor and fluctuation coefficient of variation coefficient distribution factor. When used, the real-time acquired lateral standard deviation, vertical gradient and fluctuation coefficient of variation are input into the corresponding mapping set, and the lateral standard deviation coefficient distribution factor, vertical gradient coefficient distribution factor and fluctuation coefficient of variation coefficient distribution factor are extracted.

[0034] It should be noted that the above one-to-one mapping set refers to the mapping relationship between the lateral standard deviation, vertical gradient and fluctuation coefficient of variation and their corresponding coefficient distribution factors, which can be constructed by preset interval mapping table, function model or interpolation model, etc. During system operation, when a certain variation is obtained, the system can directly find or calculate the corresponding coefficient distribution factor. Then, after normalization processing, the sum of the three coefficient distribution factors is ensured to be 1, so as to complete the weighted fusion evaluation of multiple source indicators.

[0035] The preset lateral standard deviation reference value, vertical gradient reference value and fluctuation coefficient of variation reference value in the database are extracted.

[0036] The water flow uniformity index of the straight opening section of the dry canal is a quantitative index of the dry canal section, which is jointly indicated by the transverse standard deviation, the vertical gradient and the fluctuation coefficient of variation, and the specific analysis process is as follows: the reference values corresponding to the transverse standard deviation and the vertical gradient of the dry canal section are compared with the collected transverse standard deviation and vertical gradient respectively, and the comparison results are coupled with the corresponding coefficient distribution factors to obtain the first factor of uniformity; the reference value of the fluctuation coefficient of variation is compared with the fluctuation coefficient of variation, and the comparison results are coupled with the coefficient distribution factor and the first factor of uniformity to obtain the water flow uniformity index of the straight opening section of the dry canal.

[0037] , , Wherein, F represents the water flow uniformity index, M represents the first factor of uniformity, Q0 represents the reference value of the transverse standard deviation, Q represents the transverse standard deviation, t represents the transverse standard deviation coefficient distribution factor, W represents the vertical gradient, W0 represents the reference value of the vertical gradient, y represents the vertical gradient coefficient distribution factor, R represents the fluctuation coefficient of variation, R0 represents the reference value of the fluctuation coefficient of variation, and u represents the fluctuation coefficient of variation coefficient distribution factor.

[0038] Further, the flow velocity measurement strategy is determined, and the specific analysis method is as follows: An ideal interval of the water flow uniformity index is extracted.

[0039] It should be noted that the ideal interval of the water flow uniformity index in the database is extracted.

[0040] If the water flow uniformity index is greater than or equal to the upper limit value of the water flow uniformity index interval, the uniformity state label is marked as high uniformity, and the flow velocity measurement strategy is marked as the multi-point average method.

[0041] It should be noted that if the water flow uniformity index is greater than or equal to the upper limit value of the water flow uniformity index interval, it indicates that the dispersion degree of the flow velocity in the horizontal direction within the section is extremely small, the vertical flow velocity changes gently, and the time fluctuation of the flow velocity is also at a low level, and the overall water flow state presents a high degree of uniformity and stability. In this case, the distribution rule of the flow velocity in the section is clear and consistent, and the flow velocity values of the measuring points are small, without the need for complex correction or integral calculation to accurately reflect the actual flow velocity of the section.

[0042] It should be noted that the multi-point average method uniformly arranges measuring points in the middle and on both sides of the main flow area of the section, collects the flow velocity data of each measuring point, and then obtains the average flow velocity of the section by arithmetic average.

[0043] If the water flow uniformity index is within the water flow uniformity index interval, the uniformity state label is marked as medium uniformity, and the flow velocity measurement strategy is marked as the velocity-area integral.

[0044] It should be noted that if the water flow uniformity index is in the water flow uniformity index interval, it means that the cross section flow velocity has certain dispersion in the horizontal direction, the vertical flow velocity changes in moderate amplitude, and the time fluctuation of the flow velocity is also within the controllable range. The overall flow state has not reached a high uniformity, but still maintains a relatively stable distribution characteristic. At this time, the system automatically marks the uniformity state label as medium uniformity to clearly define the distribution attribute of the current water flow. The velocity-area integral is used to avoid the error caused by the simplified calculation when the uniformity is insufficient, and to avoid introducing complex hydraulic slope correction as in the low uniformity state, which balances the calculation efficiency while ensuring the measurement accuracy.

[0045] It should be noted that the velocity-area integral collects the instantaneous flow velocity data of each measuring point, then divides the cross section into a plurality of small area units, calculates the product of the flow velocity of each unit and the corresponding area, and finally accumulates all the unit flow to obtain the total flow of the cross section. The average flow velocity is obtained by processing the ratio of the total flow of the cross section to the cross section area.

[0046] If the water flow uniformity index is less than or equal to the lower limit value of the water flow uniformity index interval, the uniformity state label is marked as low uniformity, and the flow velocity measurement strategy is marked as hydraulic slope integral correction.

[0047] It should be noted that if the water flow uniformity index is less than or equal to the lower limit value of the water flow uniformity index interval, it means that the cross section flow velocity has significant dispersion in the horizontal direction, the vertical flow velocity changes dramatically, and the time fluctuation of the flow velocity is strong. The overall flow state presents obvious uneven and disorder characteristics. At this time, the system automatically marks the uniformity state label as low uniformity to clearly define the complexity of the current water flow. By integrating the spatial variation and iterative correction logic of the hydraulic slope, the measurement error caused by the chaotic distribution of the flow velocity under the low uniformity flow state can be targeted.

[0048] When the flow velocity measurement strategy is hydraulic slope integral correction, the water flow super parameter of the straight opening cross section of the main canal is collected in real time to obtain the hydraulic slope of the straight opening cross section of the main canal. After the flow velocity of the straight opening cross section of the main canal is back calculated, iterative optimization is performed.

[0049] Further, the hydraulic slope integral correction has the following specific analysis method: The roughness of the straight opening cross section of the main canal is obtained in real time, and the sediment concentration is monitored. When the sediment concentration exceeds the sediment concentration threshold, the roughness is dynamically corrected according to the sediment concentration. An auxiliary cross section is selected upstream and downstream of the target cross section, and the hydraulic slope integral correction is performed. The specific process is as follows: It should be noted that for the straight opening section of the dry canal, the natural roughness is determined by the canal bed material, but the sediment concentration is an important dynamic factor that changes the actual roughness and needs to be corrected. When the sediment concentration is too high, part of the sediment will settle on the canal bottom or slope, forming sand ridges, silt layers, etc., which significantly increases the roughness of the canal boundary. At this time, the actual roughness will be greater than the natural roughness, resulting in an overestimation of the actual flow, which may cause excessive water supply in the downstream canal.

[0050] It should be explained that the ultrasonic sediment content meter is used to measure the sediment content in real time by inserting it into the water body. This type of equipment emits ultrasonic waves or laser light and establishes a sediment content-ultrasonic property calibration curve in advance based on the scattering and attenuation characteristics of sediment. The instrument can substitute the measured ultrasonic signal change into the curve to inversely calculate the current sediment content of the water body, enabling continuous and real-time monitoring, facilitating timely triggering of roughness correction, and dynamically correcting the roughness based on the sediment concentration. When the sediment concentration S is greater than or equal to the threshold value, the increase in sediment particles in the water will increase the internal friction resistance of the water flow and the friction resistance with the canal wall. The collision and friction between sediment particles and the interaction between sediment and the canal bottom and wall will increase the energy loss of the water flow, resulting in an increase in roughness. The roughness increases linearly with the increase in sediment concentration, which can better reflect the influence of sediment concentration on water flow resistance. Therefore, the correction formula can be set as: where k is the siltation influence coefficient, n0 represents the natural roughness, and S represents the sediment concentration, reflecting the amplitude of the increase in roughness with the increase in sediment concentration.

[0051] The hydraulic radius of the straight opening section of the dry canal is obtained in real time, the multiple of the hydraulic radius is extracted based on the uniformity index of the water flow, and the section spacing is determined based on the multiple of the hydraulic radius.

[0052] It should be noted that the hydraulic radius is the ratio of the cross-sectional area to the wet perimeter, and the wet perimeter is the length of the fluid-solid boundary contact on the section. The hydraulic radius comprehensively reflects the influence of the size and shape of the flow section on the water flow resistance.

[0053] In this embodiment, the system pre-sets the corresponding rules between the water flow uniformity index and the multiple of the hydraulic radius. These rules are included in the structured configuration file or parameter table for centralized management. In actual operation, the specific water flow uniformity index is calculated, and then the corresponding multiple of the hydraulic radius is matched from the rules based on the ratio. Different multiples of the hydraulic radius correspond to different degrees of deviation, and the configuration of the multiple of the hydraulic radius is not fixed, but is continuously optimized based on previous operation data and expert practical experience, ensuring that the configuration of the multiple of the hydraulic radius is accurate and reasonable.

[0054] It needs to be explained that the correspondence rule is specifically to establish the correlation between the water flow uniformity index and the hydraulic radius multiple. The construction of such correlation has diversity, which can be realized by preset interval mapping table, function model or interpolation model, etc. When a specific value of the water flow uniformity index is obtained during system operation, the system can directly find or calculate the hydraulic radius multiple corresponding to the water flow uniformity index according to the mapping relationship constructed.

[0055] It needs to be explained that the smaller the water flow uniformity index is, the worse the water flow uniformity is, and then in order to ensure that the collected auxiliary section has reference significance, the smaller the section spacing is, and then the smaller the multiple of the water flow uniformity corresponding to the hydraulic radius is.

[0056] It needs to be explained that the multiple of the hydraulic radius is multiplied by the hydraulic radius to obtain the section spacing. The hydraulic radius can comprehensively represent the geometric characteristics and water flow resistance characteristics of the flow section, and the spacing determined based on this can more reasonably reflect the spatial variation law of the water flow state. The multiple of the hydraulic radius is multiplied by the hydraulic radius to obtain the section spacing, because this way can make the spacing closely related to the characteristic scale of the water flow.

[0057] Real-time collection of water flow super parameters of the straight opening section of the main canal, including measurement of the upstream and downstream water levels of the auxiliary section, the upstream and downstream canal bottom elevations, the upstream and downstream water depths and the section area.

[0058] It needs to be explained that the water levels of the upstream and downstream auxiliary sections are obtained by radar water level gauge, the canal bottom elevations and the section width are preset in the collection system, the upstream and downstream water depths are obtained by subtracting the canal bottom elevations from the water levels of the upstream and downstream auxiliary sections, and the section area is obtained by multiplying the section width and the water depth.

[0059] Synchronous monitoring of the water levels (z 上 , z 下 ) of the upstream and downstream auxiliary sections, the upstream and downstream canal bottom elevations (h 底上 , h 底下 ), calculation of the upstream and downstream water depths (h 上 =z 上 -h 底上 ), (h 下 =z 下 -h 底下 ), real-time acquisition of the water area A of the straight opening section by laser scanning.

[0060] Acquisition of the initial flow velocity of the straight opening section of the main canal, calculation of the kinetic energy correction coefficient based on the initial flow velocity, obtaining of the total head difference expression based on the real-time collected parameters of the straight opening section of the main canal, and thus obtaining of the corrected hydraulic slope.

[0061] It should be noted that the initial flow velocity v of the straight opening section of the main canal is calculated based on the speed-area integral algorithm, the grid method is used to arrange measuring points on the straight opening section, the actual flow velocity s at each small unit area dA is measured, and the kinetic energy correction coefficient is calculated based on the initial flow velocity, wherein a is the kinetic energy correction coefficient, s is the actual flow velocity, v is the initial flow velocity, and A is the section area.

[0062] It should be noted that the total head difference is the total head difference value of the upstream and downstream auxiliary sections, and its expression is wherein ΔH is the total head difference, a 上 represents the kinetic energy correction coefficient of the upstream auxiliary section, a 下 represents the kinetic energy correction coefficient of the downstream auxiliary section, g represents the acceleration of gravity, h 上 represents the upstream water depth, h 下 represents the upstream water depth.

[0063] The hydraulic slope is the ratio of the total head difference to the section spacing.

[0064] Based on the Manning formula, the corrected hydraulic slope is taken as the input to inversely output the average flow velocity, which is denoted as the first corrected flow velocity.

[0065] It should be noted that the Manning formula is a classic formula for describing the relationship between the flow velocity of an open channel and the hydraulic parameters, and its expression is: wherein V is the average flow velocity, i.e., the first corrected flow velocity, n is the roughness, R is the hydraulic radius, and ΔH is the total head difference.

[0066] Further, iterative optimization is performed, and the specific analysis method is as follows: The flow velocity deviation value is obtained based on the first corrected flow velocity and the initial flow velocity.

[0067] It should be noted that the initial flow velocity is a theoretical value calculated based on basic measurement parameters, representing the expected flow velocity under an ideal flow state, which is a benchmark assumption in water conservancy engineering design and conventional monitoring. Since the actual flow influencing factors are not considered, the initial flow velocity cannot be directly used to calculate the actual flow, so the smaller the deviation value of the first corrected flow velocity and the initial flow velocity, the closer the first corrected flow velocity is to the ideal state, i.e., the better the inversely output average flow velocity state.

[0068] It should be noted that the absolute value of the first corrected flow velocity minus the initial flow velocity is denoted as the flow velocity deviation value.

[0069] The flow velocity deviation value threshold is extracted according to the flow uniformity index.

[0070] In the embodiment, the system sets the corresponding rules between the water flow uniformity index and the flow velocity deviation value threshold in advance, which are included in the structured configuration file or parameter table for centralized management. In actual operation, the specific water flow uniformity index is calculated first, and then the corresponding flow velocity deviation value threshold is matched from the rules according to the ratio. Different deviation levels correspond to different flow velocity deviation value thresholds, and the configuration of the flow velocity deviation value threshold is not fixed, but is continuously optimized combined with the past operation data and the practical experience of experts, so as to ensure that the setting of the flow velocity deviation value threshold is accurate and reasonable.

[0071] It should be explained that the corresponding rules are to establish the association between the water flow uniformity index and the flow velocity deviation value threshold. The construction method of the association has diversity, which can be realized by preset interval mapping table, function model or interpolation model, etc. When a specific value of the water flow uniformity index is obtained during system operation, the system can directly find or calculate the flow velocity deviation value threshold corresponding to the water flow uniformity index according to the mapping relationship constructed.

[0072] It should be noted that the greater the water flow uniformity index, the more uniform the flow velocity distribution, the better the stability of the flow velocity data, and the smaller deviation can reflect the abnormality of the measured value. In order to discover and correct the problem in time and ensure the measurement accuracy, the extracted flow velocity deviation value threshold is smaller.

[0073] If the flow velocity deviation value is less than the flow velocity deviation value threshold, the first corrected flow velocity is recorded as the cross-section flow velocity.

[0074] It should be noted that if the flow velocity deviation value is less than the flow velocity deviation value threshold, it means that the difference between the calculated flow velocity and the corrected flow velocity is within an acceptable range, the stability of the water flow state meets the monitoring accuracy requirement, and the actual cross-section water flow velocity can be well reflected. No additional iterative correction process is needed to avoid resource waste caused by excessive correction, so the first corrected flow velocity is recorded as the cross-section flow velocity.

[0075] If the flow velocity deviation value is greater than or equal to the flow velocity deviation value threshold, the average flow velocity is updated by back calculation, the hydraulic slope is recalculated, a new round of corrected flow velocity is back calculated, which is recorded as the second corrected flow velocity, and the relative error between the second corrected flow velocity and the initial flow velocity is calculated, which is recorded as the flow velocity relative error value.

[0076] It should be noted that the second corrected flow velocity is subtracted from the initial flow velocity to obtain the relative error.

[0077] It should be noted that if the flow velocity deviation value is greater than or equal to the flow velocity deviation value threshold, it indicates that the average flow velocity currently calculated based on the corrected hydraulic slope and dynamic roughness deviates significantly from the actual flow state, and the iterative correction mechanism needs to be started. The section spacing is extracted according to the flow velocity deviation value, and the total head difference expression is recalculated, and the kinetic energy correction coefficient is recalculated, so as to update the hydraulic slope with more accurate AH and AL.

[0078] In this embodiment, the section spacing is extracted according to the flow velocity deviation value, and the specific analysis process is as follows: the system sets the corresponding rules between the flow velocity deviation value and the new section spacing in advance, and these rules are included in the structured configuration file or parameter table for centralized management. In actual operation, the specific flow velocity deviation value is calculated first, and then the corresponding new section spacing is matched from the rules according to the ratio. Different new section spacings will correspond to different deviation levels, and the configuration of the new section spacing is not fixed, but will be continuously optimized combined with the past operation data and the practical experience of experts, so as to ensure that the setting of the new section spacing is accurate and reasonable.

[0079] It should be explained that the corresponding rules specifically establish the correlation between the flow velocity deviation value and the new section spacing. The construction method of this correlation has diversity, which can be realized by preset interval mapping table, function model or interpolation model, etc. When a specific value of the flow velocity deviation value is obtained during system operation, the system can directly find or calculate the new section spacing corresponding to the flow velocity deviation value according to the mapping relationship constructed.

[0080] If the flow velocity relative error value is greater than or equal to the flow velocity deviation value threshold, the flow velocity is reversed again.

[0081] It should be noted that if the flow velocity relative error value is greater than or equal to the flow velocity deviation value threshold, it indicates that the deviation between the current corrected flow velocity and the actual flow state has exceeded the acceptable range, which may be caused by the insufficient correction of parameters such as roughness and hydraulic slope to adapt to the complex flow state. At this time, the hydraulic slope integral correction is carried out again, and the flow velocity is reversed. The essence is to optimize the parameters through iteration to narrow the gap between theoretical calculation and actual flow velocity, and to avoid the distortion of subsequent links such as flow and scheduling decision caused by too large single calculation error.

[0082] If the flow velocity relative error value is less than the flow velocity deviation value threshold, the second corrected flow velocity is recorded as the section flow velocity.

[0083] It should be noted that if the flow velocity relative error value is less than the flow velocity deviation value threshold, it indicates that the current corrected flow velocity has met the accuracy requirement, and further iteration will increase the calculation redundancy. Therefore, the second corrected flow velocity is recorded as the section flow velocity, which can not only ensure the reliability of the result, but also balance the calculation efficiency, and conforms to the principle of adapting precision and efficiency in engineering. Therefore, the second corrected flow velocity is recorded as the section flow velocity.

[0084] A correction frequency threshold value is determined according to the flow rate deviation value and the flow rate deviation value threshold value.

[0085] It should be noted that the flow rate threshold deviation value is obtained by subtracting the flow rate deviation value threshold value from the flow rate deviation value, and the correction frequency threshold value is obtained according to the flow rate threshold deviation value.

[0086] In this embodiment, the system sets the corresponding rules between the flow rate threshold deviation value and the correction frequency threshold value in advance, and these rules are included in the structured configuration file or parameter table for centralized management. In actual operation, the specific flow rate threshold deviation value is calculated first, and then the corresponding correction frequency threshold value is matched from the rules according to the ratio. For different deviation levels, different correction frequency threshold values will be corresponded, and the configuration of the correction frequency threshold value is not fixed, but will be continuously optimized combined with the past running data and the practical experience of experts, so as to ensure that the setting of the correction frequency threshold value is accurate and reasonable.

[0087] It should be explained that the corresponding rules are to establish the association between the flow rate threshold deviation value and the correction frequency threshold value. The construction method of this association has diversity, which can be realized by preset interval mapping table, function model or interpolation model, etc. When a specific value of the flow rate threshold deviation value is obtained during system operation, the system can directly find or calculate the correction frequency threshold value corresponding to the flow rate threshold deviation value according to the mapping relationship constructed.

[0088] It should be noted that the greater the flow rate threshold deviation value, the more significant the deviation of the actual flow rate from the expected value, which means that the water flow state is more complex or there are more obvious interference factors, and more iterations are needed for correction to gradually approach the true flow rate, so as to ensure the accuracy of the measurement result, and then the extracted correction frequency threshold value should be greater.

[0089] If the relative error value of the flow rate is still greater than or equal to the flow rate deviation value threshold value when the correction frequency exceeds the correction frequency threshold value, a warning information is generated.

[0090] It should be noted that if the flow rate does not converge when the correction frequency exceeds the correction frequency threshold value, it means that the actual water flow may be in an extreme situation, and even after multiple corrections, the parameters may not converge due to unstable flow state, and at this time, unlimited iteration will cause system jam, data delay, increase hardware energy consumption and time cost.

[0091] In this embodiment, the warning information can be: "Attention! Flow rate correction cannot converge." The direction angle of the resultant velocity of the straight opening cross section of the main canal is analyzed, the flow calculation strategy of the straight opening cross section of the main canal is determined combined with the first factor of uniformity, and the spiral flow correction analysis is performed when the flow calculation strategy of the straight opening cross section of the main canal is spiral correction.

[0092] Further, the direction angle of the resultant velocity of the straight opening cross section of the dry canal is analyzed, and the specific analysis method is as follows: The spiral flow parameters are collected, including the longitudinal flow velocity, the transverse flow velocity and the vertical flow velocity of the dry canal.

[0093] The resultant velocity is analyzed based on the spiral flow parameters.

[0094] The longitudinal flow velocity is the flow velocity component along the main flow direction of the dry canal, which is the main component of the resultant velocity. The greater the value, the greater the size of the resultant velocity, and the closer the direction of the resultant velocity to the longitudinal direction. The transverse flow velocity is the flow velocity component perpendicular to the main flow direction. The greater the value, the more significant the deviation of the resultant velocity to the transverse direction, and the greater the size of the resultant velocity. The vertical flow velocity is the flow velocity component perpendicular to the water surface. The greater the value, the more significant the deviation of the resultant velocity in the vertical direction, and the greater the size of the resultant velocity.

[0095] When the longitudinal flow velocity increases, the transverse circulation is caused by the driving action of the water flow, which increases the transverse flow velocity. The turbulent action of the water flow is enhanced, which may promote the increase of the vertical flow velocity. The increase of the transverse flow velocity may induce the vortex motion in the vertical direction, thereby increasing the vertical flow velocity.

[0096] The longitudinal flow velocity can be measured by arranging the flow velocity meter along the main flow direction of the dry canal cross section to directly obtain the longitudinal flow velocity component. When measuring, the sensing direction of the instrument should be consistent with the longitudinal direction to ensure the accuracy of the data. The transverse flow velocity can be measured by arranging the flow velocity meter at different transverse positions of the dry canal cross section to measure the flow velocity component perpendicular to the main flow direction and obtain the transverse flow velocity data.

[0097] The vertical flow velocity can be measured by arranging the flow velocity meter along the plumb line direction of the dry canal cross section, and the average vertical flow velocity can be extracted by low-pass filtering.

[0098] The preset longitudinal flow velocity coefficient distribution factor, transverse flow velocity coefficient distribution factor and vertical flow velocity coefficient distribution factor in the database are extracted.

[0099] It should be noted that the value range of the longitudinal flow velocity coefficient distribution factor, the transverse flow velocity coefficient distribution factor and the vertical flow velocity coefficient distribution factor is 0 to 1, and the sum of the longitudinal flow velocity coefficient distribution factor, the transverse flow velocity coefficient distribution factor and the vertical flow velocity coefficient distribution factor is 1. The pre-set values can be directly extracted from the database during use. For example, a one-to-one mapping set is constructed by the longitudinal flow velocity, the transverse flow velocity and the vertical flow velocity corresponding to the longitudinal flow velocity coefficient distribution factor, the transverse flow velocity coefficient distribution factor and the vertical flow velocity coefficient distribution factor. During use, the real-time acquired longitudinal flow velocity, transverse flow velocity and vertical flow velocity are input into the corresponding mapping set, and the longitudinal flow velocity coefficient distribution factor, transverse flow velocity coefficient distribution factor and vertical flow velocity coefficient distribution factor are extracted.

[0100] It needs to be explained that the one-to-one mapping set above refers to establishing a mapping relationship between the longitudinal flow velocity, transverse flow velocity and vertical flow velocity and its corresponding coefficient distribution factor, which can be constructed by preset interval mapping table, function model or interpolation model, etc. In the process of system running, when a certain change is obtained, the system can directly find or calculate the corresponding coefficient distribution factor; then after normalization processing, the sum of the three coefficient distribution factors is ensured to be 1, so as to complete the weighted fusion evaluation of multi-source indicators.

[0101] Extract the preset longitudinal flow velocity reference value, transverse flow velocity reference value and vertical flow velocity reference value in the database.

[0102] The spiral flow velocity is the longitudinal flow velocity of the dry canal, and the transverse flow velocity and the vertical flow velocity jointly affect the quantitative index of the flow velocity. The specific analysis process is as follows: compare the collected longitudinal flow velocity, transverse flow velocity and vertical flow velocity with the corresponding reference values respectively, and couple the respective comparison processing results with the corresponding coefficient distribution factors to obtain the spiral flow velocity.

[0103] Wherein, G represents the spiral flow velocity, C represents the longitudinal flow velocity, C0 represents the longitudinal flow velocity reference value, j represents the longitudinal flow velocity coefficient distribution factor, D represents the transverse flow velocity, D0 represents the transverse flow velocity reference value, b represents the transverse flow velocity coefficient distribution factor, H represents the vertical flow velocity, H0 represents the vertical flow velocity reference value, and n represents the vertical flow velocity coefficient distribution factor.

[0104] Based on the spiral flow velocity, the flow velocity direction angle is obtained.

[0105] It needs to be explained that the direction angle can be directly obtained according to the inverse trigonometric function relationship, Wherein, θ is the direction angle, C represents the longitudinal flow velocity, and G represents the spiral flow velocity.

[0106] Further, the flow calculation strategy of the straight opening section of the dry canal is determined, and the specific analysis method is as follows: Extract the longitudinal axis of the canal.

[0107] Based on the flow velocity direction angle and the longitudinal axis, the flow velocity direction deviation value is obtained.

[0108] It needs to be explained that the flow velocity direction deviation value is used to quantify the deviation degree of the spiral flow velocity direction and the longitudinal axis of the canal. The preset longitudinal axis of the canal in the database is extracted, and the absolute value of the angle between the flow velocity direction angle and the longitudinal axis is obtained to obtain the flow velocity direction deviation value.

[0109] ​If the combined velocity direction deviation value is greater than or equal to the combined velocity direction deviation value threshold and the uniformity first factor is less than or equal to the uniformity first factor threshold, the flow calculation strategy is recorded as spiral correction.

[0110] It should be noted that if the combined velocity direction deviation value is greater than or equal to the combined velocity direction deviation value threshold and the uniformity first factor is less than the uniformity first factor threshold, it indicates that the water flow is in a complex flow state of strong spiral flow superimposed flow velocity distribution with high dispersion, the water flow presents obvious spiral trajectory, the traditional calculation based on longitudinal flow velocity only can underestimate the actual flow state complexity, there may be significant difference between local high flow area and low flow area, and the flow velocity fluctuates sharply with time, so the flow calculation strategy is recorded as spiral correction.

[0111] If the combined velocity direction deviation value is less than the combined velocity direction deviation value threshold and the uniformity first factor is greater than the uniformity first factor threshold, the flow calculation strategy is recorded as directly using the cross-sectional flow velocity.

[0112] It should be noted that if the combined velocity direction deviation value is less than or equal to the combined velocity direction deviation value threshold and the uniformity first factor is greater than the uniformity first factor threshold, it indicates that the spiral flow interference is small and the flow velocity distribution is uniform, the flow velocity in the cross section has small difference in transverse and vertical distribution, the flow velocity values of each measuring point are close to the average flow velocity of the cross section, and the flow velocity has weak fluctuation with time, so the cross-sectional flow velocity can accurately represent the actual motion state of the water flow, so the flow calculation strategy is recorded as directly using the cross-sectional flow velocity.

[0113] If the combined velocity direction deviation value is greater than or equal to the combined velocity direction deviation value threshold and the uniformity first factor is greater than the uniformity first factor threshold, or the combined velocity direction deviation value is less than or equal to the combined velocity direction deviation value threshold and the uniformity first factor is less than or equal to the uniformity first factor threshold, the flow calculation strategy is recorded as rechecking measurement error.

[0114] It should be noted that strong spiral flow can cause significant transverse / vertical gradient of flow velocity distribution in the cross section through rotation, while the uniformity first factor greater than the threshold indicates that the flow velocity distribution is highly uniform, which is difficult to coexist in physical mechanism. When the combined velocity direction is close to the longitudinal axis, the water flow is mainly in straight motion, and the flow velocity distribution should be relatively uniform, but the uniformity first factor less than the threshold indicates that the flow velocity is highly discrete, which violates the conventional flow state law, that is, the basic data presents a physically inexplicable contradiction, so the measurement link is preferred to be checked rather than directly applying the correction algorithm.

[0115] Further, when the flow calculation strategy of the straight opening cross section of the main canal is spiral correction, spiral flow correction analysis is performed, and the specific analysis method is as follows: The spiral flow correction coefficient is obtained according to the uniformity first factor.

[0116] In the embodiment, the system sets the corresponding rules between the first factor of uniformity and the spiral flow correction coefficient in advance, and the rules are included in the structured configuration file or parameter table for centralized management. In actual operation, the specific first factor of uniformity is calculated first, and then the corresponding spiral flow correction coefficient is matched from the rules according to the ratio. Different spiral flow correction coefficients correspond to different deviation degrees, and the configuration of the spiral flow correction coefficient is not fixed, but is continuously optimized combined with the past operation data and the practical experience of experts, so as to ensure that the setting of the spiral flow correction coefficient is accurate and reasonable.

[0117] It should be explained that the corresponding rules are to establish the association between the first factor of uniformity and the spiral flow correction coefficient. The construction method of the association has diversity, which can be realized by preset interval mapping table, function model or interpolation model, etc. When a specific value of the first factor of uniformity is obtained during system operation, the system can directly find or calculate the spiral flow correction coefficient corresponding to the first factor of uniformity according to the constructed mapping relationship.

[0118] It should be noted that the greater the first factor of uniformity, the more regular the distribution of flow rate in the horizontal and vertical directions, the lower the degree of water flow disorder, and the smaller the possibility of forming spiral flow, so the smaller the extracted spiral flow correction coefficient.

[0119] The initial flow is obtained based on the cross-sectional flow rate and the cross-sectional area.

[0120] It should be noted that the initial flow is obtained by multiplying the cross-sectional flow rate and the cross-sectional area.

[0121] The flow correction value is obtained based on the initial flow and the spiral flow correction coefficient.

[0122] It should be noted that the flow correction value is obtained by multiplying the initial flow and the spiral flow correction coefficient.

[0123] The spiral flow time threshold is extracted according to the spiral flow correction coefficient.

[0124] In the embodiment, the system sets the corresponding rules between the spiral flow correction coefficient and the spiral flow time threshold in advance, and the rules are included in the structured configuration file or parameter table for centralized management. In actual operation, the specific spiral flow time threshold is calculated first, and then the corresponding spiral flow time threshold is matched from the rules according to the ratio. Different spiral flow time thresholds correspond to different deviation degrees, and the configuration of the spiral flow time threshold is not fixed, but is continuously optimized combined with the past operation data and the practical experience of experts, so as to ensure that the setting of the spiral flow time threshold is accurate and reasonable.

[0125] It needs to be explained that the corresponding rule is to establish the association between the spiral flow correction coefficient and the spiral flow time threshold. The construction of this association has diversity, which can be realized by preset interval mapping table, function model or interpolation model, etc. When a specific value of the spiral flow correction coefficient is obtained during system operation, the system can directly find or calculate the spiral flow time threshold corresponding to the spiral flow correction coefficient according to the mapping relationship constructed.

[0126] It needs to be pointed out that the greater the spiral flow correction coefficient is, the more significant the influence of spiral flow on flow velocity and flow is. In order to ensure the sufficiency and accuracy of correction, more sufficient time is needed to complete the monitoring, calculation and adjustment of related parameters, so the extracted spiral flow time threshold should be greater.

[0127] The spiral flow duration parameter is introduced. When it is monitored that the spiral flow continuously exists for more than the spiral flow time threshold, the spiral flow correction coefficient needs to remain a fixed value.

[0128] It needs to be pointed out that when the continuous existence time of spiral flow exceeds the spiral flow time threshold, the water flow has entered the stable spiral flow stage from the transient adjustment stage. At this time, the disturbance of spiral flow to the cross section flow velocity has become a kind of persistent and regular stable factor, rather than a random or instantaneous disturbance, so the spiral flow correction coefficient needs to remain a fixed value.

[0129] If the spiral flow appears intermittently, the moving average method is used to smooth the spiral flow correction coefficient to avoid excessive fluctuation of flow data caused by frequent correction.

[0130] It needs to be pointed out that if the spiral flow appears intermittently, the moving average method is used to smooth the spiral flow correction coefficient to weaken the impact of flow state mutation on the correction parameter. The average value of the correction coefficients of the last two continuous time points is calculated as the effective correction value of the current time point, so as to realize the buffering of instantaneous jump and avoid the distortion of flow calculation result caused by frequent jump of correction coefficient.

[0131] The flow velocity verification of the straight opening section of the main canal is carried out, the flow velocity verification strategy is determined, and when the flow velocity verification strategy is the hydraulic slope correction, the flow velocity calculation of the straight opening section of the main canal is carried out again.

[0132] Further, the flow velocity verification of the straight opening section of the main canal is carried out, the flow velocity verification strategy is determined, and the specific analysis method is as follows: The absolute value of the difference between the calculated flow velocity and the average value of the flow velocities of the upstream and downstream sections is compared to obtain the first flow velocity error value, and the absolute value of the difference between the calculated flow velocity and the flow velocity at the corresponding time in the historical same period flow velocity curve is compared to obtain the second flow velocity error value.

[0133] It should be noted that the flow rate is compared with the average value of the upstream and downstream section flow rate and the historical same period flow rate curve, the upstream and downstream trends and the conventional hydrological law are verified, and the accuracy of the current flow rate calculation is verified from the spatial and temporal dimensions.

[0134] The flow rate error value is obtained based on the flow rate error first value and the flow rate error second value.

[0135] It should be noted that the flow rate error value is obtained by weighted average addition of the flow rate error first value and the flow rate error second value, the flow rate error first value is multiplied by the first proportion factor, the flow rate error second value is multiplied by the second proportion factor, and the two multiplication processing results are added to obtain the flow rate error value.

[0136] It should be noted that the sum of the first proportion factor and the second proportion factor is 1, and both are extracted according to the water flow uniformity index mapping.

[0137] If the flow rate error value is greater than or equal to the flow rate error value threshold, the flow rate verification strategy of the straight opening section of the main canal is recorded as re-performing the hydraulic slope correction, and the monitoring frequency of the spiral flow parameter is increased.

[0138] It should be noted that if the flow rate error value is greater than or equal to the flow rate error value threshold, it indicates that the current calculated flow rate deviates significantly from the reference (the average value of the upstream and downstream flow rates or the historical same period flow rate), which exceeds the acceptable range of normal hydrological fluctuations or measurement errors, and a systematic verification and correction mechanism needs to be started. Therefore, the flow rate verification strategy of the straight opening section of the main canal is recorded as re-performing the hydraulic slope correction, and the monitoring frequency of the spiral flow parameter is increased.

[0139] If the flow rate error value is less than the flow rate error value threshold, the flow rate verification strategy of the straight opening section of the main canal is recorded as outputting the verified final flow rate value, and the verified flow rate data, parameters and correction process are stored in the database. A time-stamped monitoring report is generated.

[0140] It should be noted that if the flow rate error value is less than the flow rate error value threshold, it indicates that the current calculated flow rate is consistent with the reasonable range in both horizontal comparison of upstream and downstream sections and longitudinal comparison of historical same period, and its reliability is double-verified, which marks that the data passes the verification of spatial continuity and time regularity, and the calculation result can be used as a reference.

[0141] The embodiment of the application provides a structure diagram of an automatic flow measurement system of a straight opening section of a main canal as shown in Figure 2 The processing flow of the system can include the following steps: uniformity analysis module, flow rate correction module, spiral flow correction module, and flow rate verification module.

[0142] The uniformity analysis module is configured to collect the uniformity parameters of the water flow of the straight opening section of the dry canal, analyze the uniformity index of the water flow of the straight opening section of the dry canal, and determine the flow velocity measurement strategy.

[0143] The flow velocity correction module is configured to collect the parameters of the straight opening section of the dry canal in real time when the flow velocity measurement strategy is the hydraulic slope integral correction, obtain the hydraulic slope of the straight opening section of the dry canal, back-calculate the flow velocity of the straight opening section of the dry canal, and perform iterative optimization.

[0144] The spiral flow correction module is configured to analyze the direction angle of the resultant velocity of the straight opening section of the dry canal, determine the flow calculation strategy of the straight opening section of the dry canal in combination with the first factor of the uniformity, and perform spiral flow correction analysis when the flow calculation strategy of the straight opening section of the dry canal is the spiral correction.

[0145] The flow velocity verification module is configured to perform the flow velocity verification of the straight opening section of the dry canal, determine the flow velocity verification strategy, and re-calculate the flow velocity of the straight opening section of the dry canal when the flow velocity verification strategy is the hydraulic slope correction. Referring to Figure 4 As shown in the mind map of the automatic flow measurement system of the straight opening section of the dry canal provided by the embodiment of the application, the water flow uniformity index of the dry canal section is first constructed, and the flow velocity calculation method is selected according to the index. Then, the relevant data are obtained, the flow velocity is corrected in combination with the sediment concentration and the hydraulic slope, and an alarm is triggered if the correction does not converge. The spiral flow parameters are calculated, it is judged whether the flow velocity is corrected, and the error needs to be reviewed in some cases. Then, the flow velocity is reviewed, and if the deviation exceeds the threshold value, the flow velocity is recalculated and the data are recorded to generate a report. Finally, the initial flow is calculated based on the verified flow velocity and the water passing section area, and the correction is performed and the influence is indicated when there is a high risk of spiral flow or the sediment concentration exceeds the threshold value.

[0146] The above-described embodiments can be implemented in whole or in part by software, hardware (e.g., circuitry), firmware, or any combination thereof. When implemented in software, the above-described embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions according to the embodiments of the present application are entirely or partially generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center through a wired (e.g., infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center, etc. containing one or more available medium collections. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium can be a solid-state disk.

[0147] It should be understood that the term "and / or" herein merely describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after it, but it can also represent an "and / or" relationship, which can be understood according to the context before and after it.

[0148] In the present application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions means any combination of these items, including any combination of single item or multiple items. For example, at least one of a, b, or c can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0149] It should be understood that in various embodiments of the present application, the size of the sequence number of the above-described processes does not mean the order of execution, and the execution order of the processes should be determined according to their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0150] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0151] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the devices, apparatuses and units described above can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0152] In several embodiments provided by the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, for example, the division of units is only a logical function division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0153] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0154] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0155] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0156] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for automatic flow measurement of a dry channel straight open section, characterized in that, The method comprises: Collecting the uniformity parameter of the water flow of the straight opening section of the dry canal, analyzing the uniformity index of the water flow of the straight opening section of the dry canal, and determining the flow velocity measurement strategy; When the flow velocity measurement strategy is hydraulic slope integral correction, the water flow super parameter of the straight opening section of the dry canal is collected in real time to obtain the hydraulic slope of the straight opening section of the dry canal, the flow velocity of the straight opening section of the dry canal is back calculated, and iterative optimization is performed; Analyzing the direction angle of the resultant velocity of the straight opening section of the dry canal, combining the first factor of uniformity to determine the flow calculation strategy of the straight opening section of the dry canal, and performing spiral flow correction analysis when the flow calculation strategy of the straight opening section of the dry canal is spiral correction; Performing flow velocity verification of the straight opening section of the dry canal, determining the flow velocity verification strategy, and when the flow velocity verification strategy is hydraulic slope correction, re-performing the flow velocity calculation of the straight opening section of the dry canal.

2. The method of claim 1, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The specific analysis method of the uniformity index of the water flow of the straight opening section of the dry canal is as follows: Collecting the uniformity parameter of the water flow of the dry canal section, including the transverse standard deviation, the vertical gradient and the fluctuation coefficient of variation; Based on the uniformity parameter of the water flow of the dry canal section, the uniformity index of the water flow of the straight opening section of the dry canal is analyzed; The uniformity index of the water flow of the straight opening section of the dry canal is the quantitative index of the transverse standard deviation, the vertical gradient and the fluctuation coefficient of variation of the dry canal section, and the specific analysis process is as follows: the reference values corresponding to the transverse standard deviation and the vertical gradient of the dry canal section are compared with the collected transverse standard deviation and vertical gradient respectively, each comparison result is coupled with the corresponding coefficient distribution factor to obtain the first factor of uniformity, the reference value of the fluctuation coefficient of variation is compared with the fluctuation coefficient of variation, and the comparison result is coupled with the coefficient distribution factor and the first factor of uniformity to obtain the uniformity index of the water flow of the straight opening section of the dry canal.

3. The method of claim 2, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The specific analysis method of determining the flow velocity measurement strategy is as follows: Extracting the ideal interval of the uniformity index of the water flow; If the uniformity index of the water flow is greater than or equal to the upper limit value of the uniformity index interval, the uniformity state label is marked as high uniformity, and the flow velocity measurement strategy is marked as the multi-point average method; If the uniformity index of the water flow is within the uniformity index interval, the uniformity state label is marked as medium uniformity, and the flow velocity measurement strategy is marked as the velocity-area integral; If the uniformity index of the water flow is less than or equal to the lower limit value of the uniformity index interval, the uniformity state label is marked as low uniformity, and the flow velocity measurement strategy is marked as hydraulic slope integral correction.

4. The method of claim 3, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The specific analysis method of the hydraulic slope integral correction is as follows: Real-time acquisition of the roughness of the straight opening section of the dry canal, monitoring of the sediment concentration, when the sediment concentration exceeds the sediment concentration threshold, dynamically correcting the roughness according to the sediment concentration, selecting one auxiliary section on the upstream and downstream of the target section, and performing hydraulic slope integral correction, the specific process is as follows: Real-time acquisition of the hydraulic radius of the straight opening section of the dry canal, extraction of the multiple of the hydraulic radius according to the uniformity index of the water flow, and determination of the section distance based on the multiple of the hydraulic radius; Real-time collection of the water flow super parameter of the straight opening section of the dry canal, including the upstream and downstream water levels, the upstream and downstream canal bottom elevations, the upstream and downstream water depths and the section area of the auxiliary section. An initial flow rate of the straight opening section of the dry canal is obtained, a kinetic energy correction coefficient is calculated based on the initial flow rate, a total water head difference expression is obtained based on the real-time collected straight opening section parameters of the dry canal, and thus a corrected hydraulic slope is obtained; Based on the Manning formula, the corrected hydraulic slope is taken as an input, and thus an average flow rate is output by backstepping, which is recorded as a first corrected flow rate.

5. The method of claim 1, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The iterative optimization is performed, and the specific analysis method is as follows: A flow rate deviation value is obtained based on the first corrected flow rate and the initial flow rate; A flow rate deviation value threshold is extracted according to a flow uniformity index; If the flow rate deviation value is less than the flow rate deviation value threshold, the first corrected flow rate is recorded as a section flow rate; If the flow rate deviation value is greater than or equal to the flow rate deviation value threshold, the average flow rate obtained by backstepping is used to update the total water head loss, the hydraulic slope is recalculated, a new round of corrected flow rate is backstepped, which is recorded as a second corrected flow rate, a relative error of the second corrected flow rate and the initial flow rate is calculated, which is recorded as a flow rate relative error value; If the flow rate relative error value is greater than or equal to the flow rate deviation value threshold, the flow rate backstepping is performed again; If the flow rate relative error value is less than the flow rate deviation value threshold, the second corrected flow rate is recorded as the section flow rate; A correction times threshold is determined according to the flow rate deviation value and the flow rate deviation value threshold; If the flow rate does not converge after the correction times exceed the correction times threshold, a warning information is generated.

6. The method of claim 1, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The direction angle of the resultant velocity of the straight opening section of the dry canal is analyzed, and the specific analysis method is as follows: Spiral flow parameters, including the longitudinal flow rate, the transverse flow rate and the vertical flow rate of the dry canal, are collected; The resultant velocity is analyzed based on the spiral flow parameters; The spiral flow resultant velocity is a quantitative index of the combined influence of the longitudinal flow rate, the transverse flow rate and the vertical flow rate of the dry canal on the resultant velocity, and the specific analysis process is as follows: the collected longitudinal flow rate, transverse flow rate and vertical flow rate are compared with corresponding reference values respectively, and each comparison result is coupled with a corresponding coefficient distribution factor for coupling processing to obtain the spiral flow resultant velocity; The direction angle of the resultant velocity is obtained based on the spiral flow resultant velocity.

7. The method of claim 1, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The flow calculation strategy of the straight opening section of the dry canal is determined, and the specific analysis method is as follows: The longitudinal axis of the canal is extracted; A resultant velocity direction deviation value is obtained based on the direction angle of the resultant velocity and the longitudinal axis; If the resultant velocity direction deviation value is greater than or equal to a resultant velocity direction deviation value threshold and the uniformity first factor is less than or equal to a uniformity first factor threshold, the flow calculation strategy is recorded as spiral correction; If the resultant velocity direction deviation value is less than the resultant velocity direction deviation value threshold and the uniformity first factor is greater than the uniformity first factor threshold, the flow calculation strategy is recorded as directly using the section flow rate; If the resultant velocity direction deviation value is greater than or equal to the resultant velocity direction deviation value threshold and the uniformity first factor is greater than the uniformity first factor threshold, or the resultant velocity direction deviation value is less than or equal to the resultant velocity direction deviation value threshold and the uniformity first factor is less than or equal to the uniformity first factor threshold, the flow calculation strategy is recorded as rechecking measurement error.

8. The method of claim 1, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, When the flow calculation strategy of the straight opening section of the dry canal is spiral correction, spiral flow correction analysis is performed, and the specific analysis method is as follows: A spiral flow correction coefficient is obtained according to the uniformity first factor; An initial flow rate is obtained based on the section flow rate and the section area; The flow correction value is obtained based on the initial flow and the helical flow correction coefficient; The helical flow time threshold is extracted according to the helical flow correction coefficient; The helical flow duration parameter is introduced, and when the helical flow continuously exists for more than the helical flow time threshold, the helical flow correction coefficient needs to be kept as a fixed value; If the helical flow appears intermittently, the sliding average method is used to smooth the helical flow correction coefficient, so as to avoid that the flow data fluctuates too much due to frequent correction.

9. The method of claim 1, wherein the dry channel straight opening cross section automatic flow measurement method is characterized by, The flow velocity verification of the straight opening section of the dry channel is performed, and the flow velocity verification strategy is determined, and the specific analysis method is as follows: The absolute value of the difference between the calculated flow velocity and the average value of the flow velocities of the upstream and downstream sections is compared to obtain a first flow velocity error value, and the absolute value of the difference between the calculated flow velocity and the flow velocity at the corresponding time in the historical same period flow velocity curve is checked to obtain a second flow velocity error value; The flow velocity error value is obtained based on the first flow velocity error value and the second flow velocity error value; If the flow velocity error value is greater than or equal to the flow velocity error value threshold, the flow velocity verification strategy of the straight opening section of the dry channel is recorded as re-performing the hydraulic slope correction, and the monitoring frequency of the helical flow parameter is increased; If the flow velocity error value is less than the flow velocity error value threshold, the flow velocity verification strategy of the straight opening section of the dry channel is recorded as outputting the final verified flow velocity value, and the verified flow velocity data, parameters and correction process are stored in the database to generate a monitoring report with a time stamp.

10. An automatic flow measuring system for a straight open section of a trunk conduit, for implementing the method according to any one of claims 1 to 9, characterized in that, The system comprises a uniformity analysis module, a flow velocity correction module, a helical flow correction module and a flow velocity verification module; The uniformity analysis module is used to collect the water flow uniformity parameters of the straight opening section of the dry channel, analyze the water flow uniformity index of the straight opening section of the dry channel, and determine the flow velocity measurement strategy; The flow velocity correction module is used to collect the parameters of the straight opening section of the dry channel in real time when the flow velocity measurement strategy is the hydraulic slope integral correction, obtain the hydraulic slope of the straight opening section of the dry channel, and perform iterative optimization after inversely deducing the flow velocity of the straight opening section of the dry channel; The helical flow correction module is used to analyze the direction angle of the resultant velocity of the straight opening section of the dry channel, determine the flow calculation strategy of the straight opening section of the dry channel in combination with the first uniformity factor, and perform helical flow correction analysis when the flow calculation strategy of the straight opening section of the dry channel is the helical correction; The flow velocity verification module is used to perform the flow velocity verification of the straight opening section of the dry channel, determine the flow velocity verification strategy, and perform the flow velocity calculation of the straight opening section of the dry channel again when the flow velocity verification strategy is the hydraulic slope correction.

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