Method for measuring trajectory of high dam rear flip water tongue

Abstract

The invention belongs to the technical field of hydraulic prototype observation of water conservancy and hydropower engineering, and relates to a method for measuring a high dam rear flip water tongue trajectory, the position of a station point M is determined, the point N is arranged on a dam plane, and the point MN is parallel to a dam axis; fixed points or two easily measured points on the high dam are marked as A1 and A2, alpha1 and alpha2 are plane angles of A1 and A2, a cross cursor of an eyepiece of the total station is adjusted to be aligned with water surface measuring points on a nappe track, vertical angles corresponding to the water surface measuring points are recorded, the horizontal distance between sections of the water surface measuring points is solved through the horizontal angles, and the water surface elevation is solved through the vertical angles. According to the method, the high dam rear flip water tongue trajectory can be rapidly and accurately obtained, and reliable data support is provided for engineering operation scheduling, hydraulic structure design and related research.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic prototype observation of water conservancy and hydropower engineering, and relates to a method for measuring the trajectory of a high dam's post-dam bucket jet. BACKGROUND

[0002] In the prototype observation of high dam discharge structures, the trajectory of the post-dam bucket jet is a key parameter, so the early-stage research will simulate the trajectory of the post-dam bucket jet through model tests and numerical simulation. However, in model tests, the model is difficult to simulate air resistance due to the similarity ratio problem between the model and the engineering prototype, resulting in a large difference between the trajectories of the bucket jet of the engineering prototype and the model. In addition, in high dam discharge structures, the water flow falls from a high place and interacts with air, generating a large amount of air bubbles and forming complex water-air two-phase flow phenomena, which involve complex interactions between water flow and air bubbles, bidirectional coupling characteristics, multi-scale problems, and turbulent effects. Numerical simulation is difficult to accurately describe the physical phenomena, and requires a large amount of computing resources. At present, there is no ideal theoretical model. Therefore, after the completion of the project, the trajectory of the water jet of the engineering prototype needs to be measured and compared with the model test and numerical simulation. On the one hand, it can better support the operation and scheduling of the project and ensure the safe operation of the project. On the other hand, it can be compared with the model test to better study the similarity ratio between the prototype and the model, thereby supporting the improvement and calibration of the early-stage research method, and the related parameters of the mathematical model can also be calibrated.

[0003] However, during the discharge of high dams, a large amount of air is entrained when the water flow is discharged at high speed, forming an air entrainment phenomenon. The air entrainment also affects the trajectory of the water jet, causing changes in the shape and position of the water jet, which increases the complexity and uncertainty of the water jet trajectory measurement.

[0004] Currently, the commonly used methods for measuring the trajectory of the post-dam water jet include the three-dimensional camera method and the total station instrument without prism method. The three-dimensional camera method takes pictures of the water jet trajectory from different angles through two cameras, and then locates the water jet trajectory according to the known coordinate points to obtain the water jet trajectory. This method has the characteristics of relatively safe observation and simple measurement, but it only starts from the image processing point of view. The water jet trajectory often has no clear boundary between the water jet and the surrounding air due to air entrainment, and the accuracy is relatively poor. The method of positioning the water jet trajectory using the total station instrument without prism method has weak light reflection signals in areas with a lot of fog and moisture, which has the risk of measurement failure.

[0005] In summary, the existing water jet trajectory measurement methods have certain limitations and cannot meet the demand for rapid and accurate measurement. SUMMARY

[0006] The present application provides a method for measuring the trajectory of a high dam's post-dam bucket jet, which meets the demand for rapid and accurate measurement of the trajectory of a high dam's post-dam water jet.

[0007] The technical solution of the present application is implemented in the following steps: S1, determining the position of the station point M, N points are arranged on the dam plane, MN is parallel to the dam axis; selecting a fixed point or two points easy to measure on the high dam as A1 and A2, and α1 and α2 are the plane angles of A1 and A2; S2, performing the water tongue trajectory measurement behind the dam, including the following steps: S2-1, aligning the water surface measuring points A3, A4, A5, A6, …, A n on the water tongue trajectory by adjusting the crosshair of the telescope of the total station, and recording the horizontal angles α3, α4, α5, α6, …, α n corresponding to the water surface measuring points respectively, and the vertical angles β3, β4, β5, β6, …, β n corresponding to the water surface measuring points respectively; S2-2, calculating the horizontal distances NA3', NA4', NA5', NA6' … NA n ' and the lengths of MA3', MA4', MA5', MA6', …, MA n ' between the water surface measuring points cross sections from the horizontal angles α3, α4, α5, α6, …, α n and the length of MN: NA3'=MN×tanα3 MA3'=MN / cosα3 … NA n '=MN×tanα n MA n '=MN / cosα n calculating the water surface elevations A3A3', A4A4', A5A5', A6A6', …, A n A n ' from the lengths of MA3', MA4', MA5', MA6', …, MA n and the vertical angles β3, β4, β5, β6, …, β n : A3A3'=M A3'×tanβ3 … A n A n '=MA n '×tanβ n calculating the cross section distances NA3', NA4', NA5', NA6' … NA n ' and the elevations A3A3', A4A4', A5A5', A6A6', …, A n An , draw the water tongue trajectory line.

[0008] As an embodiment, the method for determining the position of the measuring station M and the lengths of MN, the plane angles a1 and a2 in S1 is to set up a total station on the coordinates of the known points on site, set as the M point, and align the horizontal angles a1 and a2 corresponding to the water surface measuring points A1 and A2 by adjusting the crosshair of the total station.

[0009] As another embodiment of the present application, the method for determining the position of the measuring station M and the lengths of MN, the plane angles a1 and a2 in S1 is to set up a total station arbitrarily according to the position on site, comprising the following steps: S11 finds a suitable observation site, sets up a total station and levels it; S12 adjusts the crosshair of the total station, aligns the water surface measuring points A1 and A2, records the lengths of MA1 and MA2 and the corresponding horizontal angles and vertical angles b1 and b2, and calculates the lengths of the horizontal distances MA1', MA2', A1A1' and A2A2' as follows: MA1'=cosb1xMA1 MA2'=cosb2xMA2 A1A1'=sinb1xMA1 A2A2'=sinb2xMA2 The horizontal position of the measuring station M is determined by the lengths of the horizontal distances MA1' and MA2' by the triangular intersection method, and the lengths of MN and the horizontal angles a1 and a2 corresponding to the water surface measuring points A1 and A2 are calculated; The lengths of the water surface elevations A1A1' and A2A2' are recorded, and the elevation of the M point is calculated as follows: The elevation of the M point = the elevation of A1 + A1A1'; Then the accurate position of the M point is obtained; S13 rotates the horizontal angle of the total station to be perpendicular to the flow direction by the plane angles a1 and a2, and then adjusts the zero; finds a point S on MN as a prism point, and then fixes M and S for the second time to set up the instrument.

[0010] The present application adopts a prism point in the measurement process, the prism serves as a reflecting device to receive and reflect the light signals emitted by the total station, so as to realize accurate ranging and orientation, effectively avoiding the defect that the reflected light signal of the total station is weak in the area with more fog and moisture, resulting in measurement failure, and the method can quickly and accurately obtain the trajectory of the bucket flow water tongue behind the high dam, providing reliable data support for engineering operation scheduling, hydraulic structure design and related research. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a logic block diagram of the measuring method of the trajectory of the bucket flow water tongue behind the high dam; Figure 2 is a schematic diagram of determining the position of a measuring station M according to an embodiment of the present application; Figure 3 is a sectional view of parameters related to determining the position of a measuring station M according to an embodiment of the present application; Figure 4 is a plan view of measuring the trajectory of a water jet behind a dam according to an embodiment of the present application; Figure 5 is a longitudinal sectional view of measuring the trajectory of a water jet behind a dam according to an embodiment of the present application. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0013] Embodiment: To verify the feasibility of the above method, taking the measurement of the trajectory of a water jet of a discharge structure of a certain hydropower station as an example, the position coordinates of point M are known, a total station is erected at the known coordinate point, the length of MN and the plane angles a1 and a2 are obtained, wherein MN is parallel to the dam axis, and then the trajectory of the water jet is measured: the total station is adjusted to aim at the water surface measurement point to record the horizontal angle and the vertical angle, the horizontal distance and the elevation of each section of the measurement point are calculated according to the trigonometric function relationship, and finally the trajectory line of the water jet is drawn.

[0014] The elevation of point M is known to be 1224.9 m, a total station is erected at point M, and the length of MN and the plane angles a1 and a2 are obtained directly from the CAD drawing, wherein MN is parallel to the dam axis. By adjusting the crosshair of the eyepiece of the total station to aim at the water surface measurement points A3, A4, A5 and A6, the horizontal angles a3, a4, a5 and a6 and the vertical angles b3, b4, b5 and b6 corresponding to each measurement point are recorded respectively, that is, a3=5.024°, a4=16.430°, a5=25.594°, a6=33.288° and b3=5.664°, b4=15.717°, b5=26.833°, b6=38.164°. The horizontal distances NA3', NA4', NA5' and NA6' and the lengths of MA3', MA4', MA5' and MA6' between the sections of the water surface measurement points can be obtained from the horizontal angles a3, a4, a5 and a6 and the length of MN, that is, NA3'=MN×tan a3=9.95 m MA3'=MN / cos a3=113.63 m The rest of the measuring points are calculated according to the same logic to obtain NA4'=33.38m, NA5'=54.22m, NA6'=74.32m, MA4'=118.01m, MA5'=125.51m, MA6'=135.41m; The water surface elevations A3A3', A4A4', A5A5', A6A6' can be obtained from the vertical angles β3, β4, β5, β6 and the lengths of MA3', MA4', MA5', MA6' as follows: A3A3'=MA3'tanβ3=11.27m; The rest of the measuring points are calculated according to the same logic to obtain A4A4'=33.21m, A5A5'=63.49m, A6A6'=106.42m; The water tongue trajectory is plotted according to the section distances NA3', NA4', NA5', NA6' and the elevations A3A3', A4A4', A5A5', A6A6' between the measuring points.

Claims

1. A method for measuring trajectory of a high dam flip bucket jet, characterized in that The following steps are implemented: S1, determining the position of the measuring station M, N points are arranged on the dam plane, MN is parallel to the dam axis; selecting fixed points or two points easy to measure on the high dam as A1 and A2, and α1 and α2 are the plane angles of A1 and A2; S2, measuring the water tongue trajectory behind the dam, including the following steps: S2-1, align the crosshair of the total station eyepiece with the water surface measuring points A3, A4, A5, A6, …, A on the water jet trajectory by adjusting n ; record the horizontal angles α3, α4, α5, α6, …, α n corresponding to the water surface measuring points, respectively, and the vertical angles β3, β4, β5, β6, …, β n corresponding to the water surface measuring points, respectively. S2-2 is obtained from the horizontal angles a3, a4, a5, a6,..., a n The horizontal distances NA3', NA4', NA5', NA6',..., NA between the cross sections of the water surface measuring points and the MN are determined from the lengths of the MN n The horizontal distances MA3', MA4', MA5', MA6',..., MA between the cross sections of the water surface measuring points and the MA are determined from the lengths of the MA n ' NA3'= MN x tan α3; MA3'= MN / cos α3; … NA n = MN x tan a n ; MA n = MN / cos α n ; The water surface elevation A3, A4, A5, A6,..., A is calculated from the vertical angles β3, β4, β5, β6,..., β n MA3, MA4, MA5, MA6,..., MA n ' and the length of MA3, MA4, MA5, MA6,..., MA n A n ' : A3 A3'= M A3' x tan β3; … A n A n '=MA n '×tanβ n ; The water tongue trajectory is plotted by the section distances NA3', NA4', NA5', NA6'…NA n and the elevations A3 A3', A4 A4', A5 A5', A6 A6', …, A n A n ' between the measuring points.

2. The method for measuring trajectory of a bucket dam pick-up flow jet according to claim 1, characterized in that The method for determining the position of the measuring station M, the length of MN, and the plane angles α1 and α2 in S1 is to erect a total station instrument on the coordinates of the known points on the site, set it as the M point, and align the horizontal angles α1 and α2 corresponding to the water surface measuring points A1 and A2 through adjusting the crosshair of the total station instrument.

3. The method of claim 1, wherein the method is characterized by The method for determining the position of the measuring station M, the length of MN, and the plane angles α1 and α2 in S1 is to erect a total station instrument on the coordinates of the known points on the site, set it as the M point, and align the horizontal angles α1 and α2 corresponding to the water surface measuring points A1 and A2 through adjusting the crosshair of the total station instrument. S11, finding a suitable observation site, erecting a total station instrument and leveling it; S12, adjusting the crosshair of the total station instrument, aligning the water surface measuring points A1 and A2, recording the lengths of MA1 and MA2 and the corresponding horizontal angles and vertical angles β1 and β2, and calculating the lengths of MA1', MA2', A1A1', and A2A2' as follows: MA1'= cos β1 x MA1; MA2'= cos β2 x MA2; A1A1'= sin β1 x MA1; A2A2'= sin β2 x MA2; The horizontal position of the measuring station M is determined by the lengths of MA1' and MA2' through the triangular intersection method, and the length of MN and the horizontal angles α1 and α2 corresponding to the water surface measuring points A1 and A2 are calculated; The lengths of A1A1' and A2A2' are recorded, and the elevation of M point is calculated as follows: The elevation of M point = the elevation of A1 + A1A1'; Then, the accurate position of M point is obtained; S13, rotating the horizontal angle of the total station instrument to be perpendicular to the water flow direction according to the plane angles α1 and α2, and then adjusting it to zero; finding a point S on MN as the prism point, and then marking and fixing M and S for the second erection of the instrument.

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