Method and device for computing old reservoir practical weir discharge coefficient

Abstract

The present application relates to the technical field of assessment of discharge capacities of practical weirs, and discloses a method and device for computing an old reservoir practical weir discharge coefficient. The method comprises: obtaining reservoir overflow weir test data, performing a model test on the basis of the reservoir overflow weir test data, and determining a curve of practical weir water level and discharge flow rate; and obtaining old reservoir practical weir parameters, and computing an old reservoir practical weir discharge coefficient on the basis of a weir flow and orifice outflow theory, the old reservoir practical weir parameters, and the curve of practical weir water level and discharge flow rate, wherein the old reservoir practical weir discharge coefficient is used for assessing the flood discharge capacity of a practical weir of an old reservoir affected by climate change. In the present application, the effects of weir flow and orifice outflow are taken into account in the process of computing an old reservoir practical weir discharge coefficient, thereby implementing accurate computation of the discharge coefficient of a practical weir of an old reservoir affected by climate change, and laying a foundation for accurate assessment of the discharge capacity of the practical weir of the old reservoir.

Description

A method and device for calculating the practical weir discharge coefficient of an old reservoir Technical Field

[0001] The present application relates to the technical field of practical weir discharge capacity assessment, and in particular to a method and device for calculating the discharge coefficient of a practical weir of an old reservoir. Background Art

[0002] Due to global climate change, the inflow conditions of many older reservoirs have changed significantly, primarily manifesting in a significant increase in peak inflows. This has posed challenges to the operation and management of these reservoirs. To address this challenge, many older reservoirs have opted to install retaining walls on the dam crest to enhance their discharge capacity, while ensuring dam safety.

[0003] Since the spillway of old reservoirs is different from the weir type and pier shape recommended in the current specifications, after the retaining wall is installed on the dam top, the trumpet mouth or road above the spillway will have a certain impact on the outflow from the orifice, resulting in the inability to determine the flow coefficient of the practical weir of old reservoirs affected by climate change, and thus the inability to accurately assess the discharge capacity of the practical weir of old reservoirs.

[0004] Summary of the Invention

[0005] In view of this, the present application provides a method and device for calculating the flow coefficient of the practical weir of an old reservoir, so as to solve the problem that the flow coefficient of the practical weir of an old reservoir affected by climate change cannot be determined, and thus the discharge capacity of the practical weir of the old reservoir cannot be accurately evaluated.

[0006] In a first aspect, the present application provides a method for calculating the practical weir discharge coefficient of an old reservoir, the method comprising:

[0007] Obtain reservoir overflow weir test data, conduct model tests based on the reservoir overflow weir test data, and determine the curve of practical weir water level and discharge flow;

[0008] Obtain the practical weir parameters of old reservoirs, and calculate the practical weir discharge coefficient of old reservoirs based on the practical weir parameters of old reservoirs and the curve of practical weir water level and discharge flow according to the weir flow and orifice outflow theory; among them, the practical weir discharge coefficient of old reservoirs is used to evaluate the flood discharge capacity of practical weirs of old reservoirs affected by climate change.

[0009] This embodiment provides a method for calculating the discharge coefficient of a practical weir of an old reservoir. The method calculates the discharge coefficient of the practical weir of the old reservoir based on the theory of weir flow and orifice outflow, the parameters of the practical weir of the old reservoir, and a curve showing the water level of the practical weir and the discharge rate. The method takes the influence of weir flow and orifice outflow into account during the calculation of the discharge coefficient of the practical weir of the old reservoir, thereby achieving accurate calculation of the discharge coefficient of the practical weir of the old reservoir affected by climate change. Furthermore, the method achieves a precise assessment of the discharge capacity of the practical weir of the old reservoir that adopts the engineering measure of raising the dam crest, thereby providing a scientific basis for renovation plans for old reservoirs affected by climate change.

[0010] In an optional embodiment, a model test is conducted based on reservoir overflow weir test data to determine a curve of practical weir water level and discharge flow, including:

[0011] Constructing overflow dam hydraulic model based on reservoir overflow weir test data;

[0012] The overflow dam hydraulic model is used to test the overflow dam water level and discharge flow under different working conditions, and a curve of practical weir water level and discharge flow is generated.

[0013] This embodiment provides a method for calculating the practical weir discharge coefficient of an old reservoir. The method uses an overflow dam hydraulic model to test the overflow dam head and downstream flow under different working conditions, and generates a curve of the practical weir water level and discharge flow. This achieves accurate testing of the curve of the practical weir water level and discharge flow, laying the foundation for the subsequent determination of the fitting coefficient and critical water level.

[0014] In an optional embodiment, according to the weir flow and orifice outflow theory, the practical weir discharge coefficient of the old reservoir is calculated based on the practical weir parameters of the old reservoir and the curve of the practical weir water level and discharge flow, including:

[0015] Determine the fitting coefficient and critical water level based on the curve of practical weir water level and discharge flow;

[0016] Determine the number of gate holes, net width of gate holes, and weir crest water level based on the practical weir parameters of old reservoirs, and calculate the theoretical flow of the practical weir of old reservoirs based on the number of gate holes, net width of gate holes, and weir crest water level;

[0017] Calculate the measured discharge of the practical weir of the old reservoir based on the fitting coefficient, critical water level, weir top water level and the theoretical discharge of the practical weir of the old reservoir;

[0018] The discharge coefficient of the practical weir of the old reservoir is calculated based on the theoretical flow of the practical weir of the old reservoir and the measured flow of the practical weir of the old reservoir.

[0019] This embodiment provides a method for calculating the discharge coefficient of a practical weir of an old reservoir. The method determines the fitting coefficient and the critical water level based on a curve of the practical weir water level and the discharge flow, and calculates the discharge coefficient of the practical weir of the old reservoir based on the theoretical flow and the measured flow of the practical weir of the old reservoir. The method takes into account the influence of the weir flow and the orifice outflow, and provides a scientific basis for the evaluation and calculation of the discharge capacity of a practical weir that adopts the installation of a retaining wall on the weir top to cope with the impact of climate change, as well as the safe operation of the practical weir of the old reservoir.

[0020] In an optional embodiment, determining the fitting coefficient and the critical water level based on a curve of the practical weir water level and the discharge flow rate includes:

[0021] The curves of practical weir water level and discharge volume are divided into weir flow curve and orifice outflow curve;

[0022] Fitting the weir flow curve and the orifice outflow curve to obtain a first fitting curve and a second fitting curve;

[0023] A fitting coefficient is determined based on the first fitting curve and the second fitting curve, and a water level corresponding to an intersection of the first fitting curve and the second fitting curve is used as a critical water level.

[0024] This embodiment provides a method for calculating the practical weir discharge coefficient of an old reservoir. The method divides the curves of the practical weir water level and the discharge flow according to different types of curves corresponding to the weir flow and the orifice outflow, and fits the weir flow curve and the orifice outflow curve to determine the fitting coefficient and the critical water level. This achieves accurate determination of the fitting coefficient and the critical water level, and enables the subsequent calculation of the practical weir discharge coefficient of the old reservoir to fully consider the influence of the weir flow and the orifice outflow, thereby improving the accuracy of the practical weir discharge coefficient of the old reservoir.

[0025] In an optional embodiment, the discharge coefficient of the practical weir of the old reservoir is calculated based on the theoretical flow of the practical weir of the old reservoir and the measured flow of the practical weir of the old reservoir, wherein the calculation formula of the discharge coefficient of the practical weir of the old reservoir is as follows:

[0026] In the above formula, m f represents the discharge coefficient of the practical weir of the old reservoir, Q1 represents the measured discharge of the practical weir of the old reservoir, Q2 represents the theoretical discharge of the practical weir of the old reservoir, a1, a2, a3, a4 and a5 represent fitting coefficients, H represents the weir top water level, H d Indicates the design water level, H c Indicates the critical water level.

[0027] In an optional embodiment, the method further includes:

[0028] Verify the practical weir discharge coefficient of old reservoirs and generate verification results of the practical weir discharge coefficient of old reservoirs.

[0029] This embodiment provides a method for calculating the flow coefficient of a practical weir of an old reservoir. By verifying the flow coefficient of the practical weir of an old reservoir, the calculation method of the flow coefficient of the practical weir of an old reservoir meets actual engineering needs. It provides a scientific basis for evaluating and calculating the discharge capacity of a practical weir that adopts the installation of a retaining wall on the weir top to cope with the impact of climate change, as well as for the safety allowability of the practical weir of an old reservoir.

[0030] In an optional embodiment, verifying the practical weir discharge coefficient of the old reservoir and generating a verification result of the practical weir discharge coefficient of the old reservoir includes:

[0031] Obtain a practical weir hydraulic model with a retaining wall installed on the dam crest, conduct model tests using the practical weir hydraulic model with a retaining wall installed on the dam crest, and generate measured discharge coefficients;

[0032] Calculate the relative error based on the practical weir discharge coefficient of old reservoirs and the measured discharge coefficient;

[0033] The relative error is compared with the preset threshold, and the verification result of the practical weir discharge coefficient of the old reservoir is determined based on the comparison result.

[0034] This embodiment provides a method for calculating the practical weir flow coefficient of an old reservoir. Model tests are conducted using a practical weir hydraulic model with a retaining wall installed on the dam top. The relative error between the practical weir flow coefficient of the old reservoir and the measured flow coefficient is calculated to verify the practical weir flow coefficient of the old reservoir, thereby ensuring the calculation accuracy of the practical weir flow coefficient of the old reservoir and providing a scientific basis for renovation plans for old reservoirs affected by climate change.

[0035] In a second aspect, the present application provides a device for calculating the practical weir discharge coefficient of an old reservoir, the device comprising:

[0036] The test module is used to obtain reservoir overflow weir test data, conduct model tests based on the reservoir overflow weir test data, and determine the curve of practical weir water level and discharge flow;

[0037] The calculation module is used to obtain the practical weir parameters of old reservoirs and calculate the practical weir discharge coefficient of old reservoirs based on the practical weir parameters of old reservoirs and the curve of practical weir water level and discharge flow according to the weir flow and orifice outflow theory. Among them, the practical weir discharge coefficient of old reservoirs is used to evaluate the flood discharge capacity of practical weirs of old reservoirs affected by climate change.

[0038] In a third aspect, the present application provides a computer device comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to thereby execute the method for calculating the practical weir flow coefficient of an old reservoir according to the first aspect or any corresponding embodiment thereof.

[0039] In a fourth aspect, the present application provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for calculating the practical weir flow coefficient of an old reservoir according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0041] FIG1 is a flow chart of a method for calculating a practical weir discharge coefficient of an old reservoir according to an embodiment of the present application;

[0042] FIG2 is a flow chart of another method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application;

[0043] FIG3 is a flow chart of another method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application;

[0044] FIG4 is a flow chart of another method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application;

[0045] FIG5 is a schematic diagram of a practical weir hydraulic model with a retaining wall installed on the dam top according to an embodiment of the present application;

[0046] FIG6 is a schematic diagram of a water level measuring needle according to an embodiment of the present application;

[0047] FIG7 is a flow chart of calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application;

[0048] FIG8 is a structural block diagram of a device for calculating a practical weir discharge coefficient of an old reservoir according to an embodiment of the present application;

[0049] FIG9 is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0050] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0051] After implementing the engineering measure of adding a retaining wall to the dam crest, the reservoir's spillway discharge capacity and discharge pattern will undergo a significant shift. When the reservoir water level is below the original dam crest, the spillway's discharge capacity will remain unchanged. However, once the reservoir water level exceeds a certain level, the spillway's discharge will no longer remain in an overflow state and will instead flow through the orifice, altering its discharge capacity. Therefore, the discharge capacity of older reservoirs that employ this type of engineering measure to address the impacts of climate change must be reassessed, particularly for operating conditions exceeding the original design water level.

[0052] Due to older designs or diverging standards, spillways in older reservoirs often differ from the weir and pier configurations recommended in current standards. Furthermore, the installation of retaining walls on the dam crest can affect outflow from the orifice, which is affected by the presence of a vent or road above the spillway. Consequently, existing formulas for outflow from practical weirs or orifices cannot be directly applied to assess the discharge capacity of practical weirs affected by climate change.

[0053] Therefore, an embodiment of the present application provides a method for calculating the practical weir flow coefficient of an old reservoir, which is applied to mobile terminals such as mobile phones and tablet computers. The calculation formula for the practical weir flow coefficient affected by climate change is derived through theoretical derivation and experimental verification to achieve the effect of accurately calculating the practical weir flow coefficient of the old reservoir.

[0054] According to an embodiment of the present application, an embodiment of a method for calculating the practical weir discharge coefficient of an old reservoir is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0055] In this embodiment, a method for calculating the practical weir discharge coefficient of an old reservoir is provided, which can be used in the above-mentioned mobile terminals, such as mobile phones, tablet computers, etc. FIG1 is a flow chart of a method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application. As shown in FIG1 , the process includes the following steps:

[0056] Step S101: Acquire reservoir overflow weir test data, conduct a model test based on the reservoir overflow weir test data, and determine a curve of practical weir water level and discharge flow.

[0057] Step S102: Obtain the practical weir parameters of the old reservoir, and calculate the practical weir discharge coefficient of the old reservoir based on the practical weir parameters of the old reservoir and the curve of the practical weir water level and discharge flow according to the weir flow and orifice outflow theory; wherein the practical weir discharge coefficient of the old reservoir is used to evaluate the flood discharge capacity of the practical weir of the old reservoir affected by climate change.

[0058] Specifically, based on hydraulics theory, when the reservoir water level exceeds a certain level, it will be affected by buildings above the overflow weir, such as trumpet mouths or highway bridges, and the water flow over the weir will form orifice outflow, and vice versa, it will be weir flow; when the water flow over the weir forms weir flow, the comprehensive flow coefficient and the weir top water level are in a quadratic polynomial relationship; when the water flow over the weir forms orifice outflow, the comprehensive flow coefficient of the thin-walled small orifice is usually a constant and has nothing to do with the water level. However, considering the existence of influencing factors such as orifice type, piers, and vertical contraction, it is assumed that the practical weir flow coefficient of old reservoirs is in a linear relationship with the weir top water level.

[0059] This embodiment provides a method for calculating the discharge coefficient of a practical weir of an old reservoir. The method calculates the discharge coefficient of the practical weir of the old reservoir based on the theory of weir flow and orifice outflow, the parameters of the practical weir of the old reservoir, and a curve showing the water level of the practical weir and the discharge rate. The method takes the influence of weir flow and orifice outflow into account during the calculation of the discharge coefficient of the practical weir of the old reservoir, thereby achieving accurate calculation of the discharge coefficient of the practical weir of the old reservoir affected by climate change. Furthermore, the method achieves a precise assessment of the discharge capacity of the practical weir of the old reservoir that adopts the engineering measure of raising the dam crest, thereby providing a scientific basis for renovation plans for old reservoirs affected by climate change.

[0060] In this embodiment, a method for calculating the practical weir discharge coefficient of an old reservoir is provided, which can be used in the above-mentioned mobile terminal, such as a mobile phone, a tablet computer, etc. FIG2 is a flow chart of a method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application. As shown in FIG2 , the process includes the following steps:

[0061] Step S201: Acquire reservoir overflow weir test data, conduct a model test based on the reservoir overflow weir test data, and determine a curve of practical weir water level and discharge flow.

[0062] Specifically, the above step S201 includes:

[0063] Step S2011: constructing an overflow dam hydraulic model based on reservoir overflow weir test data.

[0064] Step S2012: using the overflow dam hydraulic model to test the overflow dam water level and discharge flow under different working conditions, and generate a curve of practical weir water level and discharge flow.

[0065] Step S202: Obtain the practical weir parameters of the old reservoir. Based on the weir flow and orifice outflow theory, the practical weir discharge coefficient of the old reservoir is calculated based on the practical weir parameters and the curve of the practical weir water level and discharge rate. The practical weir discharge coefficient of the old reservoir is used to assess the flood discharge capacity of the old reservoir's practical weir under the influence of climate change. For details, please refer to step S102 of the embodiment shown in Figure 1 and will not be repeated here.

[0066] This embodiment provides a method for calculating the practical weir discharge coefficient of an old reservoir. The method uses an overflow dam hydraulic model to test the overflow dam head and downstream flow under different working conditions, and generates a curve of the practical weir water level and discharge flow. This achieves accurate testing of the curve of the practical weir water level and discharge flow, laying the foundation for the subsequent determination of the fitting coefficient and critical water level.

[0067] In this embodiment, a method for calculating the practical weir discharge coefficient of an old reservoir is provided, which can be used in the above-mentioned mobile terminal, such as a mobile phone, a tablet computer, etc. FIG3 is a flow chart of a method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application. As shown in FIG3 , the process includes the following steps:

[0068] Step S301: Obtain reservoir overflow weir test data, conduct a model test based on the reservoir overflow weir test data, and determine a curve of practical weir water level and discharge flow. Please refer to step S201 of the embodiment shown in Figure 2 for details, which will not be repeated here.

[0069] Step S302: Obtain the practical weir parameters of the old reservoir and calculate the practical weir discharge coefficient of the old reservoir based on the practical weir parameters and the curve of the practical weir water level and discharge flow according to the weir flow and orifice outflow theory. The practical weir discharge coefficient of the old reservoir is used to evaluate the flood discharge capacity of the practical weir of the old reservoir affected by climate change.

[0070] Specifically, the above step S302 includes:

[0071] Step S3021: Determine the fitting coefficient and critical water level based on the curve of practical weir water level and discharge flow.

[0072] In some optional implementations, the above step S2021 includes:

[0073] Step a1: dividing the curve of practical weir water level and discharge flow into a weir flow curve and an orifice outflow curve.

[0074] Specifically, due to the different laws of the water level and flow curves of weir flow and orifice outflow, and combined with the different flow patterns of weir flow and orifice outflow, that is, the water flow will not contact the buildings on the weir during weir flow, and the water flow will fit the buildings on the weir during orifice outflow, the curves of practical weir water level and discharge volume are divided into weir flow curve and orifice outflow curve.

[0075] Step a2: fitting the weir flow curve and the orifice outflow curve to obtain a first fitting curve and a second fitting curve.

[0076] Step a3: determining a fitting coefficient based on the first fitting curve and the second fitting curve, and taking the water level corresponding to the intersection of the first fitting curve and the second fitting curve as the critical water level.

[0077] Specifically, the water level values ​​at different positions in the fitting curve and their corresponding flow rates are input into the calculation formula of the practical weir flow coefficient of the old reservoir to obtain the fitting coefficient.

[0078] Step S3022: Determine the number of gate holes, the net width of the gate holes, and the weir top water level based on the practical weir parameters of the old reservoir, and calculate the theoretical flow of the practical weir of the old reservoir based on the number of gate holes, the net width of the gate holes, and the weir top water level.

[0079] Specifically, the theoretical flow rate of orifice outflow and weir flow without considering the effects of energy loss and contraction, that is, the calculation formula for the theoretical flow rate Q2 of the practical weir of the old reservoir is as follows:

[0080] In the above formula, n represents the number of gate holes, b represents the net width of the gate hole, the unit is m (meter), g represents the acceleration of gravity, H represents the water level at the top of the weir, and the unit of Q2 is m 3 / s (cubic meters per second).

[0081] Alternatively, when the weir crest water level exceeds the critical water level, the water flow over the weir changes from weir flow to orifice outflow. After the water flows out of the orifice, a contraction section is formed. The water depth of the contraction section is related to the weir crest water level. Therefore, the theoretical flow formula of the orifice outflow without considering the energy loss and contraction effect is:

[0082] In the above formula, e represents the water depth of the contraction section of the orifice outflow. In order to unify the theoretical flow formulas of weir flow and orifice outflow, let e = ∈H, ∈ represents the contraction coefficient, that is, the ratio of the water depth e of the contraction section of the outflow to the weir top water level H; the influence of ∈ is taken into account in the discharge coefficient and is not considered in the theoretical flow formula for the time being.

[0083] Step S3023 , calculating the measured flow of the practical weir of the old reservoir based on the fitting coefficient, the critical water level, the weir top water level and the theoretical flow of the practical weir of the old reservoir.

[0084] Specifically, the calculation formula for the measured flow rate Q1 of the practical weir of the old reservoir is as follows:

[0085] In the above formula, a1, a2, a3, a4 and a5 represent fitting coefficients, H represents the weir top water level, and H d Indicates the design water level, H cIndicates the critical water level.

[0086] Step S3024: Calculate the discharge coefficient of the practical weir of the old reservoir based on the theoretical flow of the practical weir of the old reservoir and the measured flow of the practical weir of the old reservoir.

[0087] Specifically, the calculation formula for the practical weir discharge coefficient of old reservoirs is as follows:

[0088] In the above formula, m f represents the practical weir discharge coefficient of the old reservoir, m f The comprehensive discharge coefficient includes the lateral contraction caused by the pier, the flow velocity and water level, and other factors. Q1 represents the measured discharge of the practical weir of the old reservoir, Q2 represents the theoretical discharge of the practical weir of the old reservoir, a1, a2, a3, a4 and a5 represent the fitting coefficients, H represents the weir top water level, H d Indicates the design water level, H c Indicates the critical water level.

[0089] This embodiment provides a method for calculating the discharge coefficient of a practical weir of an old reservoir. The method determines the fitting coefficient and the critical water level based on a curve of the practical weir water level and the discharge flow, and calculates the discharge coefficient of the practical weir of the old reservoir based on the theoretical flow and the measured flow of the practical weir of the old reservoir. The method takes into account the influence of the weir flow and the orifice outflow, and provides a scientific basis for the evaluation and calculation of the discharge capacity of a practical weir that adopts the installation of a retaining wall on the weir top to cope with the impact of climate change, as well as the safe operation of the practical weir of the old reservoir.

[0090] In this embodiment, a method for calculating the practical weir discharge coefficient of an old reservoir is provided, which can be used in the above-mentioned mobile terminal, such as a mobile phone, a tablet computer, etc. FIG4 is a flow chart of a method for calculating the practical weir discharge coefficient of an old reservoir according to an embodiment of the present application. As shown in FIG4 , the process includes the following steps:

[0091] Step S401: Obtain reservoir overflow weir test data, conduct a model test based on the reservoir overflow weir test data, and determine a curve of practical weir water level and discharge flow. Please refer to step S301 of the embodiment shown in Figure 3 for details, which will not be repeated here.

[0092] Step S402: Obtain the practical weir parameters of the old reservoir. Based on the weir flow and orifice outflow theory, the practical weir discharge coefficient of the old reservoir is calculated based on the practical weir parameters and the curve of the practical weir water level and discharge rate. The practical weir discharge coefficient of the old reservoir is used to assess the flood discharge capacity of the old reservoir's practical weir under the influence of climate change. For details, please refer to step S302 of the embodiment shown in Figure 3 and will not be repeated here.

[0093] Step S403: verifying the practical weir discharge coefficient of the old reservoir and generating a verification result of the practical weir discharge coefficient of the old reservoir.

[0094] Specifically, a practical weir hydraulic model with a retaining wall installed on the dam top is obtained, and a model test is carried out using the practical weir hydraulic model with a retaining wall installed on the dam top to generate a measured flow coefficient; the relative error is calculated based on the practical weir flow coefficient of the old reservoir and the measured flow coefficient; the relative error is compared with a preset threshold, and the verification result of the practical weir flow coefficient of the old reservoir is determined based on the comparison result.

[0095] Optionally, as shown in Figure 5, the practical weir hydraulic model with a retaining wall installed on the dam top consists of an electromagnetic flowmeter, a reservoir, an inlet channel, and a practical weir with a retaining wall installed on the dam top; as shown in Figure 6, the water level probe is arranged at the reservoir wall 1.0m (60m for the prototype) in front of the practical weir, with a measurement accuracy of 0.1mm; the electromagnetic flowmeter has an accuracy of 0.5%; the practical weir model is a normal model designed according to the gravity similarity criterion, and the model scale is 1:60; the practical weir hydraulic model with a retaining wall installed on the dam top is supported by plexiglass, the model manufacturing error is ±0.1mm, and the model assembly error is controlled within ±1mm; among them, in Figure 5, 1 represents the water level probe, 2 represents the orifice outflow water surface line, 3 represents the weir flow surface line, 4 represents the pier, 5 represents the building on the weir, 6 represents the retaining wall installed on the dam top, and 7 represents the practical weir.

[0096] Optionally, based on the water level-flow data and the observation of flow state in the experiment, the water level-flow curve is divided into two groups under the condition that the water level-flow relationship changes significantly, corresponding to the weir flow water level-flow relationship and the orifice outflow water level-flow relationship, and the water level-flow fitting curves of the weir flow and orifice outflow are obtained by fitting respectively. The water level corresponding to the intersection of the two curves is the critical water level.

[0097] Alternatively, the measured flow coefficient m is calculated according to the following formula:

[0098] Alternatively, the measured discharge coefficients are used to determine the fitting coefficients in the above formula (4), and then the above formula (3) is used to evaluate the discharge capacity of the practical weir of the old reservoir.

[0099] Optionally, the calculated value of the practical weir flow coefficient affected by climate change (i.e., the practical weir flow coefficient of the old reservoir) is compared with the measured flow coefficient, and the relative error is calculated. The relative error is compared with the allowable error range (i.e., the preset threshold) to obtain the verification result of the practical weir flow coefficient of the old reservoir.

[0100] This embodiment provides a method for calculating the flow coefficient of a practical weir of an old reservoir. By verifying the flow coefficient of the practical weir of an old reservoir, the calculation method of the flow coefficient of the practical weir of an old reservoir meets actual engineering needs. It provides a scientific basis for evaluating and calculating the discharge capacity of a practical weir that adopts the installation of a retaining wall on the weir top to cope with the impact of climate change, as well as for the safety allowability of the practical weir of an old reservoir.

[0101] The following is a specific example to illustrate the specific steps of a method for calculating the practical weir discharge coefficient of an old reservoir.

[0102] Example 1:

[0103] As shown in Figure 7, the specific steps of a method for calculating the practical weir discharge coefficient of an old reservoir include:

[0104] Step 1: derive the flow coefficient calculation formula. The specific process is as follows:

[0105] First, based on hydraulic theory, when the reservoir water level exceeds a certain level, it will be affected by structures above the overflow weir, such as bellmouths or highway bridges, and the water flowing over the weir will form an orifice outflow, and vice versa, a weir flow. When the water flowing over the weir forms a weir flow, the comprehensive discharge coefficient and the weir crest water level have a quadratic polynomial relationship. When the water flowing over the weir forms an orifice outflow, the comprehensive discharge coefficient of a thin-walled small orifice is usually a constant and independent of the water level. However, considering the existence of influencing factors such as orifice type, piers, and vertical contraction, it is assumed that the practical weir discharge coefficient of old reservoirs has a linear relationship with the weir crest water level:

[0106] The calculation formula for the theoretical flow rate Q2 of the practical weir of the old reservoir is as follows:

[0107] From formulas (1-1) and (1-2), we can conclude that:

[0108] The flow coefficient and flow calculation formula derived above are a unified calculation formula based on practical weir flow and orifice outflow theory.

[0109] Step 2: Create a hydraulic model of the overflow weir based on the relevant parameters of the reservoir overflow weir;

[0110] Step 3. By testing the overflow dam head and discharge flow under different working conditions, determine the curve of head and discharge flow according to the test results of different working conditions; find the water level at which the water level-flow relationship in the curve changes significantly, and combine the flow state observed in the test to divide the curve into two parts: weir flow and orifice outflow; fit the two parts of the curve separately to obtain the fitting curve of the two curves; the water level corresponding to the intersection of the two fitting curves is the critical water level; solve the comprehensive flow coefficient corresponding to different weir heads and discharge flows according to the formula of comprehensive flow coefficient of weir flow, and determine the fitting coefficient.

[0111] Step 4: Input the fitting coefficient and critical water level into formula (1-1) to obtain the practical weir discharge coefficient of the old reservoir.

[0112] Step 5: The model test obtains the measured and calculated values ​​of the discharge coefficient to verify the calculation accuracy of the formula.

[0113] The practical weir hydraulic model with a retaining wall installed on the dam top consists of an electromagnetic flowmeter, a reservoir, an inlet channel, and a practical weir with a retaining wall installed on the dam top. During the test, based on the water level-flow data and the observation of the flow state in the experiment, the water level-flow curve was divided into two groups under the condition that the water level-flow relationship changed significantly. These two groups correspond to the weir flow water level-flow relationship and the orifice outflow water level-flow relationship, respectively. The water level-flow fitting curves of the weir flow and orifice outflow were obtained by fitting them respectively. The water level corresponding to the intersection of the two curves is the critical water level. In this example, H c =569.76m.

[0114] Then, the measured flow coefficient is calculated according to the formula:

[0115] In the above formula, Q1 is the measured flow rate of the practical weir of the old reservoir in the experiment, b = 0.208m, and n = 3. The measured flow coefficients are then used to fit the coefficients in formula (1-1) respectively, and then formula (1-3) is used to evaluate the discharge capacity; in this example, a1 = -0.0910, a2 = 0.2435, a3 = 0.3292, a4 = -0.2705, and a5 = 0.7591.

[0116] The calculated values ​​of the practical weir discharge coefficients affected by climate change (i.e., the practical weir discharge coefficients of old reservoirs) were compared with the measured discharge coefficients, and their relative errors were calculated. The calculation results of the relative errors are shown in Table 1 below.

[0117] Table 1:

[0118] As shown in Table 1 above, the model test results verifying the derived discharge coefficient calculation formula show that the relative error between the practical weir discharge coefficient of old reservoirs affected by climate change and the measured discharge coefficient is within 3%, and the accuracy is within the allowable error range, which can meet actual engineering needs.

[0119] This embodiment also provides a device for calculating the practical weir discharge coefficient of an old reservoir. This device is used to implement the above-mentioned embodiments and optional implementations. Details already described are not repeated here. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0120] This embodiment provides a device for calculating the practical weir discharge coefficient of an old reservoir, as shown in FIG8 , including:

[0121] The test module 801 is used to obtain reservoir overflow weir test data, conduct a model test based on the reservoir overflow weir test data, and determine a curve of practical weir water level and discharge flow;

[0122] Calculation module 802 is used to obtain the practical weir parameters of old reservoirs and calculate the practical weir discharge coefficient of old reservoirs based on the practical weir parameters of old reservoirs and the curve of practical weir water level and discharge flow according to the weir flow and orifice outflow theory. The practical weir discharge coefficient of old reservoirs is used to evaluate the flood discharge capacity of the practical weirs of old reservoirs affected by climate change.

[0123] In some optional embodiments, the test module 801 includes:

[0124] A construction unit, used to construct an overflow dam hydraulic model based on reservoir overflow weir test data;

[0125] The test unit is used to test the overflow dam water level and discharge flow under different working conditions using the overflow dam hydraulic model, and generate curves of practical weir water level and discharge flow.

[0126] In some optional implementations, the calculation module 802 includes:

[0127] a determination unit for determining a fitting coefficient and a critical water level based on a curve of a practical weir water level and a discharge flow;

[0128] The first calculation unit is used to determine the number of gate holes, the clear width of the gate holes and the weir top water level based on the practical weir parameters of the old reservoir, and calculate the theoretical flow of the practical weir of the old reservoir based on the number of gate holes, the clear width of the gate holes and the weir top water level;

[0129] The second calculation unit is used to calculate the measured flow of the practical weir of the old reservoir based on the fitting coefficient, the critical water level, the weir top water level and the theoretical flow of the practical weir of the old reservoir;

[0130] The third calculation unit is used to calculate the discharge coefficient of the practical weir of the old reservoir based on the theoretical flow of the practical weir of the old reservoir and the measured flow of the practical weir of the old reservoir.

[0131] In some optional implementations, the determining unit includes:

[0132] A sub-unit is used to divide the curve of practical weir water level and discharge flow into a weir flow curve and an orifice discharge curve;

[0133] A fitting subunit, for fitting the weir flow curve and the orifice outflow curve to obtain a first fitting curve and a second fitting curve;

[0134] The determination subunit is configured to determine a fitting coefficient based on the first fitting curve and the second fitting curve, and to use a water level corresponding to an intersection of the first fitting curve and the second fitting curve as a critical water level.

[0135] In some optional implementations, the calculation formula for the practical weir discharge coefficient of the old reservoir in the third calculation unit is as follows:

[0136] In the above formula, m f represents the discharge coefficient of the practical weir of the old reservoir, Q1 represents the measured discharge of the practical weir of the old reservoir, Q2 represents the theoretical discharge of the practical weir of the old reservoir, a1, a2, a3, a4 and a5 represent fitting coefficients, H represents the weir top water level, H d Indicates the design water level, H c Indicates the critical water level.

[0137] In some optional embodiments, the method further includes:

[0138] The verification module is used to verify the practical weir discharge coefficient of the old reservoir and generate the verification result of the practical weir discharge coefficient of the old reservoir.

[0139] In some optional implementations, the verification module includes:

[0140] a generating unit for obtaining a practical weir hydraulic model with a retaining wall installed on the dam crest, performing a model test using the practical weir hydraulic model with a retaining wall installed on the dam crest, and generating a measured discharge coefficient;

[0141] A fourth calculation unit is used to calculate a relative error based on the practical weir discharge coefficient of the old reservoir and the measured discharge coefficient;

[0142] The comparison unit is used to compare the relative error with a preset threshold value, and determine the verification result of the practical weir discharge coefficient of the old reservoir based on the comparison result.

[0143] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0144] In this embodiment, a calculation device for the practical weir discharge coefficient of an old reservoir is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0145] An embodiment of the present application further provides a computer device having a calculation device for the practical weir discharge coefficient of an old reservoir as shown in FIG8 .

[0146] Please refer to Figure 9, which is a schematic diagram of the structure of a computer device provided in an optional embodiment of the present application. As shown in Figure 9, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in or on the memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 9 takes a processor 10 as an example.

[0147] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may also optionally include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0148] The memory 20 stores instructions that can be executed by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0149] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0150] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0151] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means, and FIG9 shows a bus connection as an example.

[0152] The input device 30 can receive input digital or character information and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touch pad, an indicator stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display, and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0153] The embodiments of the present application also provide a computer-readable storage medium. The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; optionally, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0154] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A method for calculating the practical weir discharge coefficient of an old reservoir, characterized in that: The method comprises: Acquiring reservoir overflow weir test data, conducting a model test based on the reservoir overflow weir test data, and determining a curve of practical weir water level and discharge flow; Obtain practical weir parameters of old reservoirs, and calculate the practical weir discharge coefficient of old reservoirs based on the practical weir parameters of old reservoirs and a curve of the practical weir water level and discharge flow according to the weir flow and orifice outflow theory; wherein the practical weir discharge coefficient of old reservoirs is used to evaluate the flood discharge capacity of the practical weirs of old reservoirs affected by climate change.

2. The method according to claim 1, characterized in that The model test is conducted based on the reservoir overflow weir test data to determine the curve of practical weir water level and discharge flow, including: Constructing a hydraulic model of the overflow dam based on the reservoir overflow weir test data; The overflow dam hydraulic model is used to test the overflow dam water level and discharge flow under different working conditions to generate the curve of the practical weir water level and discharge flow.

3. The method according to claim 1 or 2, characterized in that The calculation of the practical weir discharge coefficient of the old reservoir based on the weir flow and orifice outflow theory, the practical weir parameters of the old reservoir and the curve of the practical weir water level and discharge flow includes: Determining a fitting coefficient and a critical water level based on a curve of the practical weir water level and discharge flow; Determining the number of gate holes, the net width of the gate holes, and the weir top water level based on the practical weir parameters of the old reservoir, and calculating the theoretical flow of the practical weir of the old reservoir based on the number of gate holes, the net width of the gate holes, and the weir top water level; Calculating the measured flow of the practical weir of the old reservoir based on the fitting coefficient, the critical water level, the weir top water level and the theoretical flow of the practical weir of the old reservoir; The flow coefficient of the practical weir of the old reservoir is calculated based on the theoretical flow of the practical weir of the old reservoir and the measured flow of the practical weir of the old reservoir.

4. The method according to claim 3, characterized in that The determining of the fitting coefficient and the critical water level based on the curve of the practical weir water level and discharge flow rate includes: Dividing the curve of the practical weir water level and discharge flow into a weir flow curve and an orifice outflow curve; Fitting the weir flow curve and the orifice outflow curve to obtain a first fitting curve and a second fitting curve; The fitting coefficient is determined based on the first fitting curve and the second fitting curve, and a water level corresponding to an intersection of the first fitting curve and the second fitting curve is used as the critical water level.

5. The method according to claim 3, characterized in that The flow coefficient of the practical weir of the old reservoir is calculated based on the theoretical flow of the practical weir of the old reservoir and the measured flow of the practical weir of the old reservoir, wherein the calculation formula of the flow coefficient of the practical weir of the old reservoir is as follows: In the above formula, m f represents the discharge coefficient of the practical weir of the old reservoir, Q1 represents the measured discharge of the practical weir of the old reservoir, Q2 represents the theoretical discharge of the practical weir of the old reservoir, a1, a2, a3, a4 and a5 represent fitting coefficients, H represents the weir top water level, H d Indicates the design water level, H c Indicates the critical water level.

6. The method according to claim 1, characterized in that Also includes: The practical weir discharge coefficient of the old reservoir is verified to generate a verification result of the practical weir discharge coefficient of the old reservoir.

7. The method according to claim 6, characterized in that The verifying of the practical weir discharge coefficient of the old reservoir and generating the verification result of the practical weir discharge coefficient of the old reservoir include: Obtaining a practical weir hydraulic model with a retaining wall installed on the dam crest, conducting a model test using the practical weir hydraulic model with a retaining wall installed on the dam crest, and generating a measured discharge coefficient; Calculating a relative error based on the practical weir discharge coefficient of the old reservoir and the measured discharge coefficient; The relative error is compared with a preset threshold, and a verification result of the practical weir discharge coefficient of the old reservoir is determined based on the comparison result.

8. A device for calculating the practical weir discharge coefficient of an old reservoir, characterized in that: The device comprises: A test module is used to obtain reservoir overflow weir test data, conduct a model test based on the reservoir overflow weir test data, and determine a curve of practical weir water level and discharge flow; A calculation module is used to obtain practical weir parameters of old reservoirs and calculate the practical weir discharge coefficient of old reservoirs based on the practical weir parameters of old reservoirs and a curve of the practical weir water level and discharge flow according to the weir flow and orifice outflow theory; wherein the practical weir discharge coefficient of old reservoirs is used to evaluate the flood discharge capacity of the practical weirs of old reservoirs affected by climate change.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for calculating the practical weir discharge coefficient of an old reservoir according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method for calculating the practical weir discharge coefficient of an old reservoir according to any one of claims 1 to 7.

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