Vision-based floating tunnel two-dimensional coupling vortex-induced vibration testing device and method

Abstract

The application relates to a visual-based suspension tunnel two-dimensional coupling vortex-induced vibration testing device and method. The device comprises a suspension tunnel truncated model; a boundary simulator which restricts the boundary of the suspension tunnel truncated model and allows the suspension tunnel truncated model to freely vibrate in the boundary; a wave maker and a current maker which generate waves and water flow to act on the suspension tunnel truncated model; a target point which comprises a plurality of target points and is arranged on the suspension tunnel truncated model and the boundary simulator respectively; and a visual capture device which captures the coordinate positions of the target points. The application does not contact the suspension tunnel, does not affect the flow field around the suspension tunnel, the result is more accurate, the two-dimensional coupling motion of the suspension tunnel can be measured, the lift, the resistance and the torque of the suspension tunnel can be measured, a large number of strain gauges, acceleration sensors, displacement sensors and other testing instruments are not used, the testing equipment is simple, reliable, easy to reuse and low in cost.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and in particular to a vision-based two-dimensional coupled vortex-induced vibration testing device and method for suspended tunnels. Background Technology

[0002] In recent years, as the construction areas of underwater tunnels have gradually shifted from flat rivers to bays and straits with developed channels, the submerged floating tunnel (SFT), a special underwater transportation structure that relies on buoyancy and anchor cable tension to maintain dynamic balance, has become a key research focus for countries around the world. In some places where it is difficult to build immersed tunnels or bridges, such as wide and deep straits, lakes, and rivers, floating tunnels can serve as a transportation solution. The design concept of floating tunnels was first proposed by Norwegians in 1966, but to date, no floating tunnel has been built. Currently, domestic and international research on floating tunnels mainly focuses on: (1) conceptual design of floating tunnels and research on fluid-structure coupling theory; (2) dynamic response and stability research of floating tunnels under hydrodynamic loads; (3) stress analysis and dynamic response of the floating tunnel tube under external excitation and research on the safety issues of the anchoring system; (4) dynamic response problems of the floating tunnel tube and tension leg under fluid vortex-induced action, etc.

[0003] In marine environments, when a steady current flows around certain objects, especially cylindrical objects, double rows of vortices with opposite rotational directions and regular arrangement will periodically detach from both sides of the object, forming a karman vortex street phenomenon. In suspended tunnels, the alternating detachment of vortices creates alternating lift and drag, causing vibrations in the sway and heave directions of the tube and altering the shape of the cylindrical wake. This interaction between the fluid and the resistance fluid induces vortex-induced vibration. When the frequency of vortex shedding approaches the natural frequency, the vortex shedding frequency becomes fixed at the structure's natural frequency, resulting in severe vibration. Vortex-induced vibration is a cause of fatigue damage and failure in suspended tunnels; therefore, studying the vortex-induced vibration phenomenon in suspended tunnels is essential.

[0004] Currently, there are three main methods for studying vortex-induced vibration (VEM) of structures: experimental methods, numerical methods, and semi-empirical formula methods. VEM caused by vortex shedding is a complex process involving multi-physics coupling. Physical experimental methods for studying VEM commonly include wind tunnel tests and vortex experiments in circulating water tanks or simulated pools. Numerical simulation methods, based on the different turbulence models used, can be categorized as: direct numerical simulation methods, Reynolds-averaged Navier-Stokes equations, large eddy simulation, vortex element method, and combinations of these methods. Based on the simulation method, they can be further divided into two-dimensional rigid body simulation based on elastic supports, two-dimensional vortex element simulation based on elastic bodies, discrete vortex element method simulation using three-dimensional structural interpolation integration, and full-domain simulation using a three-dimensional model of the elastic body. Currently, research on VEM of suspended tunnels mainly uses numerical simulation methods. The advantage of this method is that it allows for full-scale structural analysis; however, the boundary conditions and load conditions of numerical simulation methods deviate somewhat from reality. Semi-empirical formula methods mainly involve wake element formulas and single-degree-of-freedom formulas. Numerical simulation and semi-empirical formula methods are both conducted under ideal conditions, and their research results can be used as theoretical references, but they deviate to some extent from the vortex-induced vibration of suspended tunnels in real environments.

[0005] In comparison, experimental models more closely approximate the actual flow field, making experimental methods a more reliable and effective approach. Currently, measurements of lift, drag, and torque in aircraft wings and automobiles' vortex-induced vibrations are primarily conducted in wind tunnels using balances or weighbridges. However, due to variations in buoyancy and water pressure on these devices at different water depths, they are unsuitable for underwater structures. Current research on the physical experiments of vortex-induced vibrations in underwater structures focuses on marine risers. This research is mainly conducted in circulating water tanks and simulated pools, using strain gauges, accelerometers, and displacement sensors to test the structure's vibration response. However, these devices are expensive, and some are not reusable, resulting in high experimental costs. Installing strain gauges, accelerometers, and displacement sensors on the structure's surface inevitably alters the surrounding flow field, affecting the vortex characteristics and causing data deviations. Some testing instruments also require wiring and power, resulting in numerous cables entangled in the structure, which not only affects the structure's normal vibration response but also poses a risk of electrical leakage. Regarding Particle Image Velocimetry (PIV), the equipment is expensive and cannot measure the lift and drag generated by the suspended tunnel under the action of water flow. Currently, there is a limited amount of research on experimental methods for vortex-induced vibration of suspended tunnels, and these studies often simplify the model. In the 2020 studies by Shi Deng et al., "Experimental study on the drag forces on a twin-tube submerged floating tunnel segment model in current" and "Experimental study of vortex-induced vibration of a twin-tube submerged lloating tunnel segment model," the model was constrained to move only in one dimension. This method does not consider the two-dimensional coupled motion of the suspended tunnel body and the restoring torque experienced by the suspended tunnel in non-equilibrium positions. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies, such as physical experiments on vortex-induced vibration of underwater structures primarily using marine risers, with testing instruments mounted on the structure's surface, which inevitably alters the surrounding flow field and affects the vortex behavior, leading to data bias. Furthermore, existing research on vortex-induced vibration experiments for suspended tunnels constrains the model to move only in one dimension, resulting in low experimental accuracy. Particle image velocimetry is also problematic due to its expensive equipment and inability to measure the lift and drag generated by the suspended tunnel under water flow. Therefore, this invention provides a vision-based two-dimensional coupled vortex-induced vibration testing device and method for suspended tunnels.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a vision-based two-dimensional coupled vortex-induced vibration testing device for suspended tunnels, comprising:

[0009] Suspended tunnel truncated model;

[0010] A boundary simulator constrains the boundaries of the suspended tunnel truncated model, allowing the suspended tunnel truncated model to vibrate freely within the boundaries;

[0011] Wave generators and current generators create waves and water flow that act on the suspended tunnel truncated model;

[0012] The target points, including several, are respectively set on the suspended tunnel truncated model and the boundary simulator;

[0013] A visual capture device captures the coordinates of the target point.

[0014] The present invention employs a vision-based two-dimensional coupled vortex-induced vibration testing device for suspended tunnels. By setting a target point, the positions of the suspended tunnel truncated model and the boundary simulator are calibrated. The coordinate changes of the target point are captured by a vision capture device, enabling the acquisition of displacement data for both the suspended tunnel truncated model and the boundary simulator. This method avoids contact with the suspended tunnel truncated model, does not affect the flow field around it, and yields more accurate results. By setting the boundary simulator, the suspended tunnel truncated model can vibrate freely within the boundary, overcoming the limitations of traditional experimental methods that only achieve one-dimensional motion. This device can measure the two-dimensional coupled motion of the suspended tunnel truncated model, including lift, drag, and torque. The device does not use a large number of strain gauges, accelerometers, displacement sensors, or other testing instruments; the testing equipment is simple, reliable, reusable, and inexpensive. It can be used to measure the vortex-induced vibration response, lift, drag, and their coefficients of suspended tunnel truncated models of various shapes.

[0015] As a preferred technical solution of the present invention, the boundary simulator includes two opposing frames, which are respectively located at both ends of the suspended tunnel truncated model. Vertically arranged springs are connected to the upper and lower positions of the ends of the suspended tunnel truncated model, and horizontally arranged springs are connected to the left and right positions of the ends of the suspended tunnel truncated model. The other ends of the springs are slidably connected to the corresponding frames, and the other ends of the vertically arranged springs slide horizontally and the other ends of the horizontally arranged springs slide vertically.

[0016] As a further preferred technical solution of the present invention, the axial direction and sliding direction of the spring and the initial position of the end face of the suspended tunnel truncated model are located in the same plane.

[0017] As a further preferred embodiment of the present invention, the other end of the spring is connected to a slide rail, and the slide rail is slidably connected to the frame.

[0018] As a further preferred technical solution of the present invention, the target point includes a spring target point, a large target point and a small target point. Among the four springs connected to one of the frames, each spring has a spring target point connected to both ends. The large target point is set at the center of the end face of the corresponding suspended tunnel cut-off model, and the small target point is set at the midpoint of the radius.

[0019] As a preferred technical solution of the present invention, the visual capture device is a binocular camera.

[0020] As a preferred technical solution of the present invention, the vision-based two-dimensional coupled vortex-induced vibration testing device for suspended tunnels further includes a wave-flow water tank. One end of the wave-flow water tank is provided with a wave generator and a current generator. The boundary simulator and the suspended tunnel truncated model are immersed in the water of the wave-flow water tank. The sidewall of the wave-flow water tank is a transparent wall, and the vision capture device faces the target point through the transparent wall.

[0021] Secondly, the present invention also provides a vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels, comprising the following steps:

[0022] S1. The boundary of the suspended tunnel truncated model is simulated using a spring and a damper, wherein the damper is a sliding damper, and the elastic coefficient of the spring is measured.

[0023] S2. Allow the suspended tunnel truncated model to undergo free decay vibration, and use a computer program to calculate the natural frequency and damping of the suspended tunnel truncated model in the water using a non-contact visual measurement method.

[0024] S3. Apply waves and water flow to the suspended tunnel truncated model. Calculate the elongation of the springs using a non-contact visual measurement method and a computer program. Decompose the force on each spring in the direction of lift and drag by the rotation angle of the springs, thus calculating the constraint force of the boundary on the suspended tunnel truncated model.

[0025] S4. Using a non-contact visual measurement method, the displacement of the suspended tunnel truncated model is calculated by a computer program to obtain the vortex-induced dynamic response of the suspended tunnel truncated model, including the sway, heave and roll of the suspended tunnel truncated model, and the dimensionless displacement of the suspended tunnel truncated model under different reduced velocities is calculated.

[0026] S5. Using the constraint forces of the boundary and the inertial forces of the suspended tunnel truncated model, calculate the vortex-induced vibration lift, drag, and torque of the suspended tunnel truncated model.

[0027] The present invention employs a vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels. This method utilizes a non-contact visual measurement approach, extracting visual measurement data using a computer program. It avoids contact with the suspended tunnel truncated model, thus preserving the surrounding flow field and resulting in more accurate results. This method overcomes the limitations of traditional experimental methods that only achieve one-dimensional motion of the suspended tunnel truncated model, enabling the measurement of its two-dimensional coupled motion, including lift, drag, and torque. Furthermore, this method does not utilize numerous strain gauges, accelerometers, displacement sensors, or other testing instruments. The testing equipment is simple, reliable, reusable, and inexpensive, and can be used to measure the vortex-induced vibration response, lift, drag, and their coefficients of suspended tunnel truncated models of various shapes.

[0028] As a preferred technical solution of the present invention, step S4 is executed first, followed by step S3, or steps S3 and S4 are executed simultaneously.

[0029] As a preferred embodiment of the present invention, the computer program includes Python.

[0030] Thirdly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels as described in any of the preceding claims.

[0031] Fourthly, the present invention also provides an electronic device, comprising:

[0032] A memory on which computer programs are stored;

[0033] A processor for executing the program in the memory to implement the vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels as described in any of the preceding embodiments.

[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] 1. The present invention provides a vision-based two-dimensional coupled vortex-induced vibration testing device and method for suspended tunnels. By setting the target point, the position of the suspended tunnel truncated model and the boundary simulator is calibrated. The coordinate changes of the target point are captured by the vision capture device. The data of the vision measurement can be extracted by a computer program. This method does not come into contact with the suspended tunnel truncated model and does not affect the flow field around the suspended tunnel truncated model, resulting in more accurate results.

[0036] 2. The present invention provides a vision-based two-dimensional coupled vortex-induced vibration testing device and method for suspended tunnels. By setting simulated boundaries, the suspended tunnel truncated model can vibrate freely within the boundaries, overcoming the limitations of traditional experimental methods that only realize one-dimensional motion of the suspended tunnel truncated model. This device can realize the testing of two-dimensional coupled motion of the suspended tunnel truncated model and can measure the lift, drag and torque of the suspended tunnel truncated model.

[0037] 3. The vision-based two-dimensional coupled vortex-induced vibration testing device and method for suspended tunnels described in this invention does not use a large number of strain gauges, acceleration sensors, displacement sensors and other testing instruments. The testing equipment is simple, reliable and easy to reuse, and has low cost. It can be used to measure the vortex-induced vibration response, lift drag and its coefficients of suspended tunnel truncated models of various shapes. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the vortex-induced vibration testing device for a suspended tunnel.

[0039] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0040] Figure 3 A schematic diagram of the core components of the suspended tunnel vortex-induced vibration testing device;

[0041] Figure 4 A schematic diagram of the theoretical layout of the boundary constraints for the vortex-induced vibration testing device for a suspended tunnel;

[0042] Figure 5 A schematic diagram of the actual layout of the boundary constraints for the vortex-induced vibration testing device for a suspended tunnel.

[0043] Figure 6 This is a schematic diagram comparing the position of the suspended tunnel at a certain moment with its initial position.

[0044] Figure 7 Time-domain plot of free decay vibration of the suspended tunnel;

[0045] Figure 8 The spectrum of free vibration of the suspended tunnel;

[0046] Figure 9 This is a flowchart of the vortex-induced vibration test process for a suspended tunnel.

[0047] The diagram is labeled as follows: 1-wave generator and flow generator, 2-flow guide, 3-inlet, 4-outlet, 5-wave surface, 6-wave height meter, 7-flow velocity meter, 8-binocular camera, 9-suspended tunnel truncated model, 10-frame, 11-slide rail, 12-spring, 13-spring target point, 14-large target point, 15-small target point, 16-wave damper. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings.

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0050] Example 1

[0051] The present invention discloses a vision-based two-dimensional coupled vortex-induced vibration testing device for a suspended tunnel, comprising a wave tank, a wave generator and a current generator 1, a flow guide 2, a wave height meter 6, a flow velocity meter 7, a target point, a vision capture device, a suspended tunnel truncated model 9, a boundary simulator, and a wave damper 16.

[0052] like Figure 1 As shown, the wave-flow channel includes at least a rectangular section. The rectangular section of the wave-flow channel is elongated, meaning its length-to-width ratio is relatively large. At both ends of the rectangular section of the wave-flow channel, the wave generator and current generator 1 and the wave damper 16 are respectively installed. The wave generator and current generator 1 are connected to the flow guide 2. The wave generator and current generator 1 are used to generate waves in the wave-flow channel, such as... Figure 1 The example illustrates a wave surface 5. The flow guide 2 is used to distribute the water flow evenly. The bottom of the wave flow tank is provided with an inlet 3 and an outlet 4. The inlet 3 is used to fill the wave flow tank with water, and the outlet 4 is used to drain water. The water discharged from the outlet 4 is pumped by a circulation pump back to the inlet 3 and re-enters the wave flow tank, so that the water in the wave flow tank is recycled. In a specific embodiment, the inlet 3 is located at one end of the wave generator and the flow generator 1, and the outlet 4 is located at one end of the wave damper 16.

[0053] like Figure 1 , Figure 2 and Figure 3 As shown, the boundary simulator is used to constrain the boundary of the suspended tunnel truncated model 9 and allow the suspended tunnel truncated model 9 to vibrate freely within the boundary. Specifically, the boundary simulator includes two opposing frames 10, which are respectively located at both ends of the suspended tunnel truncated model 9. Vertically arranged springs 12 are connected to the upper and lower positions of the ends of the suspended tunnel truncated model 9, and horizontally arranged springs 12 are connected to the left and right positions of the ends of the suspended tunnel truncated model 9. The other ends of the springs 12 are slidably connected to the corresponding frames 10 through slide rails 11. The other end of the vertically arranged spring 12 slides horizontally, and the other end of the horizontally arranged spring 12 slides vertically. The axial direction and sliding direction of the spring 12 are in the same plane as the initial position of the end face of the suspended tunnel truncated model 9.

[0054] like Figure 4 As shown, this is a schematic diagram of the theoretical arrangement of the boundary constraints of the suspended tunnel vortex-induced vibration testing device. The boundary of the suspended tunnel truncated model 9 is formed by springs and dampers. In this embodiment, the boundary of the suspended tunnel truncated model 9 is simulated by the damping of the spring 12 and the slide rail 11.

[0055] like Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, the target points include several, which are respectively set on the suspended tunnel truncated model 9 and the boundary simulator. Specifically, the target points include spring target points 13, large target points 14 and small target points 15. Among the four springs 12 connected to the frame 10, each spring 12 has its two ends connected to the spring target points 13. The large target point 14 is set at the center of the end face of the suspended tunnel truncated model 9, and the small target point 15 is set at the midpoint of the radius. Preferably, the small target point 15 is located directly above the large target point 14. The spring target point 13, the large target point 14 and the small target point 15 are all circular.

[0056] In this embodiment, the size definition of the large target point 14 and the small target point 15 is simply that the size of the large target point 14 is larger than that of the small target point 15; the colors of the spring target points 13 on the four springs 12 can be different, such as... Figure 2 , Figure 3 and Figure 5The example shows that the spring target 13 above is blue, the spring target 13 below is green, the spring target 13 on the left is yellow, the spring target 13 on the right is red, and the large target 14 and the small target 15 are both black.

[0057] like Figure 1 and Figure 2 As shown, the visual capture device is used to capture the coordinate position of the target point. Specifically, the visual capture device is a binocular camera 8, which is a high-speed camera.

[0058] like Figure 1 and Figure 2 As shown, the wave height meter 6, the flow velocity meter 7, the suspended tunnel truncated model 9, and the boundary simulator are set in the middle of the rectangular section of the wave flow tank and are all submerged in the water of the wave flow tank. The waves and water flow generated by the wave generator and the flow generator 1 can act on the suspended tunnel truncated model 9 during the movement. The wave height meter 6 is used to measure the height of the wave surface 5, and the flow velocity meter 7 is used to measure the flow velocity of the water in the wave flow tank.

[0059] The sidewall of the rectangular section of the wave-flow water tank is a transparent wall. The visual capture device faces the target point through the transparent wall window. The distance between the visual capture device and the target point is controlled between 0.5m and 1.5m. The transparent wall can be made of transparent materials such as glass or acrylic.

[0060] In this embodiment, the binocular camera 8 can be replaced with a monocular camera.

[0061] This embodiment describes a vision-based two-dimensional coupled vortex-induced vibration testing device for suspended tunnels. By setting a target point to calibrate the positions of the suspended tunnel truncated model 9 and the boundary simulator, and by capturing the coordinate changes of the target point using a vision capture device, the displacement data of the suspended tunnel truncated model 9 and the boundary simulator can be obtained. This method does not involve contact with the suspended tunnel truncated model 9 and does not affect the flow field around it, resulting in more accurate results. By setting the boundary simulator, the suspended tunnel truncated model 9 can vibrate freely within the boundary, overcoming the limitations of traditional experimental methods that only achieve one-dimensional motion of the suspended tunnel truncated model 9. This device can measure the two-dimensional coupled motion of the suspended tunnel truncated model 9, including its lift, drag, and torque. This device does not use a large number of strain gauges, accelerometers, displacement sensors, or other testing instruments; the testing equipment is simple, reliable, reusable, and inexpensive. It can be used to measure the vortex-induced vibration response, lift, drag, and their coefficients of suspended tunnel truncated models 9 of various shapes.

[0062] Example 2

[0063] The present invention discloses a vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels, utilizing a vision-based two-dimensional coupled vortex-induced vibration testing device for suspended tunnels as described in Example 1. The method includes the following steps:

[0064] S1. The boundary of the suspended tunnel truncated model 9 is simulated using the spring 12 and the damper. The damper is a sliding damper. The elastic coefficient k of the spring 12 is measured. A weight of known weight is hung on the spring 12, and the elongation of the spring 12 under each different gravity is measured. The elastic coefficient k of the spring 12 can be calculated using F = k·Δx. The torsional stiffness GI of the suspended tunnel truncated model 9 under the boundary simulator is calibrated. P The whole process is as follows Figure 9 As shown in the top diagram.

[0065] S2. Give the suspended tunnel truncated model 9 an initial displacement, allowing it to undergo free decaying vibration. Take images of the suspended tunnel truncated model 9 under free vibration using the binocular camera 8. Use a computer program to plot the decay curve of the free vibration of the suspended tunnel truncated model 9 as shown below. Figure 7 As shown, the spectrum of free vibration of the suspended tunnel truncated model 9 can be obtained by Fourier transform as follows: Figure 8 As shown, the natural frequency f of the suspended tunnel truncated model 9 in the water is calculated. n And damping c.

[0066]

[0067]

[0068] ω nx =2πf nx

[0069] in m is the mass per unit length of the suspended tunnel truncated model 9, c m Let c be the inertial force coefficient; for a circular cross-section, c can be taken as... m =1, ρ is the density of water, D is the diameter of the tube body of the suspended tunnel section model 9, A0, A i The 0th and i-th peak points selected for the free decay vibration curve, i = 0, 1, 2, 3, ..., are as follows: Figure 7 As shown.

[0070] The whole process is as follows Figure 9 The middle diagram is shown.

[0071] S3. Using a non-contact visual measurement method, the displacement of the suspended tunnel truncated model 9 is calculated by a computer program to obtain the vortex-induced dynamic response of the suspended tunnel truncated model 9, including the sway, heave and roll of the suspended tunnel truncated model 9, and the dimensionless displacement of the suspended tunnel truncated model 9 under different reduced velocities is calculated.

[0072] Specifically:

[0073] The wave generator and current generator 1 are activated according to the experimental conditions, so that waves and water flow act on the suspended tunnel truncated model 9. The binocular camera 8 is used to capture video of the movement of the suspended tunnel truncated model 9. The computer program processes the video into frames and saves it as an image, and stores it in a certain path.

[0074] The Python program sequentially reads the images under this path and uses relevant code to perform Hough circle recognition, identifying the large target point 14 and the small target point 15 on the cross-section of the suspended tunnel truncated model 9 in the image. Assuming the positions at a certain moment of motion and the initial positions are as follows... Figure 6 As shown, Figure 6 The black outline represents the position at a certain moment in the motion, while the red outline represents the initial position.

[0075] Establish an xy rectangular coordinate system, with the x-axis direction being the swaying direction of the suspended tunnel truncated model 9 tube, the y-axis direction being the heave direction of the suspended tunnel truncated model 9 tube, and the rotation angle on the xy plane being the roll of the suspended tunnel truncated model 9 tube.

[0076] The center of the large target point 14 at the initial position is denoted as point M with coordinates (0, 0), and the center of the small target point 15 is denoted as N. At a certain moment, the center of the large target point 14 moves to point M' with coordinates (x, y). x and y are the sway and heave of the tube body of the suspended tunnel truncated model 9, respectively. The dimensionless displacement of the suspended tunnel truncated model 9 under different reduced velocities is calculated.

[0077] The expression for the reduced velocity is:

[0078] Where v is the water flow velocity, f n Let be the natural frequency of the suspended tunnel truncated model 9 in still water, and D be the diameter of the tube body of the suspended tunnel truncated model 9.

[0079] The expression for dimensionless displacement is:

[0080] The acceleration of the suspended tunnel section model 9 is calculated as: a x =x”,a y =y”

[0081] The vector of the initial position is obtained based on the centers of the large target point 14 and the small target point 15 on the suspended tunnel truncated model 9. The position vector at a certain moment is denoted as The angle of rotation of the suspended tunnel truncated model 9 is denoted as θ.

[0082]

[0083] θ=arccosθ

[0084] The whole process is as follows Figure 9 The bottom half of the diagram is shown on the left.

[0085] S4. Calculate the elongation of the spring 12 using a computer program, calculate the force on each spring 12, and decompose the force on the spring 12 in the direction of lift and resistance by the rotation angle of the spring 12, that is, calculate the constraint force of the boundary on the suspended tunnel cut-off model 9.

[0086] Specifically:

[0087] Waves and water flow act on the suspended tunnel truncated model 9. After the suspended tunnel truncated model 9 moves, the binocular camera 8 captures a video of the spring 12 moving. The computer program processes the video frame by frame and saves it as an image.

[0088] The Python program identifies the spring target points 13 on the spring 12. Initially, the centers of the two spring target points 13 on one of the springs 12 are recorded as A and B, respectively. At a certain moment, point A moves to A', and point B moves to B'. Figure 6 As shown, the elongation of the spring 12 is calculated using coordinates. The tension force on the spring 12 is F1 = kΔx. This force is decomposed into lift and resistance directions; let... and The included angle is α, F 1x =F1cosα, F 1y =F1sinα, and similarly calculate the tension F of the four springs 12. 2x F 2y F 3x F 3y F 4x F 4y The constraint force exerted by the boundary simulator on the suspended tunnel truncated model 9 is:

[0089]

[0090]

[0091] The inertial force of the suspended tunnel truncated model 9 is:

[0092] F ax =ma x =mx”,F ay =ma y =my”

[0093] The whole process is as follows Figure 9 The right half of the bottom diagram is shown.

[0094] S5. Using the constraint force of the boundary and the inertial force of the suspended tunnel truncated model 9, calculate the vortex-induced vibration lift, drag and torque of the suspended tunnel truncated model 9.

[0095] By calculating the first and second derivatives of the displacement of the suspended tunnel truncated model 9, the vibration equation of the suspended tunnel truncated model 9 in water can be expressed as:

[0096]

[0097]

[0098] Calculate the lift and drag coefficients.

[0099] The lift coefficient is: The drag coefficient is:

[0100] Where ρ is the density of the fluid, D is the diameter of the tube of the suspended tunnel truncated model 9, l is the length of the tube of the suspended tunnel truncated model 9, v is the flow velocity, and C... l C is the lift coefficient. d This is the drag coefficient.

[0101] Based on the relationship between torque and rotation angle The calculated torque is:

[0102] The whole process is as follows Figure 9 As shown in the bottom diagram.

[0103] In one specific implementation, step S4 is executed first, followed by step S3.

[0104] In one specific implementation, steps S3 and S4 are performed simultaneously.

[0105] In this embodiment, the binocular camera 8 can be replaced with a monocular camera.

[0106] This embodiment describes a vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels. Through a non-contact visual measurement method, data is extracted using a computer program. This method does not contact the suspended tunnel truncated model 9, thus not affecting the flow field around it, resulting in more accurate results. It overcomes the limitations of traditional experimental methods that only achieve one-dimensional motion of the suspended tunnel truncated model 9, enabling the measurement of its two-dimensional coupled motion, including lift, drag, and torque. This method does not use a large number of strain gauges, accelerometers, displacement sensors, or other testing instruments. The testing equipment is simple, reliable, reusable, and inexpensive, and can be used to measure the vortex-induced vibration response, lift, drag, and their coefficients of suspended tunnel truncated models 9 of various shapes.

[0107] Example 3

[0108] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels as described in Example 2.

[0109] Computer-readable storage media are used to store various types of data to support the operation of the electronic device. This data may include, for example, instructions for any application or method used to operate on the electronic device, as well as application-related data. The computer-readable storage medium may be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0110] Example 4

[0111] An electronic device according to the present invention includes:

[0112] A memory on which computer programs are stored;

[0113] A processor is configured to execute the program in the memory to implement the vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels as described in Embodiment 2.

[0114] As a preferred embodiment of this invention, the electronic device may include a processor, a memory, and may also include one or more of a multimedia component, an input / output (I / O) interface, and a communication component.

[0115] The processor controls the overall operation of the electronic device to complete all or part of the steps in the vision-based two-dimensional coupled vortex-induced vibration test method for suspended tunnels.

[0116] Memory is used to store various types of data to support the operation of the electronic device. This data may include, for example, instructions for any application or method used to operate on the electronic device, as well as application-related data. Memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0117] The multimedia component may include a screen and an audio component, wherein the screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals; for example, the audio component may include a microphone for receiving external audio signals, the received audio signals may be further stored in memory or transmitted via a communication component; the audio component may also include at least one speaker for outputting audio signals.

[0118] I / O interfaces provide interfaces between the processor and other interface modules, such as keyboards, mice, buttons, etc.; these buttons can be virtual buttons or physical buttons.

[0119] The communication component is used for wired or wireless communication between the electronic device and other devices; wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G or 5G, or one or more combinations thereof, and the corresponding communication component may include: Wi-Fi module, Bluetooth module, NFC module, mobile communication module.

[0120] As a preferred embodiment, the electronic device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the aforementioned vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels.

[0121] In addition, the computer-readable storage medium provided in this embodiment can be the memory including program instructions, which can be executed by the processor of an electronic device to complete the vision-based two-dimensional coupled vortex-induced vibration test method for suspended tunnels.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels, characterized in that, A vision-based two-dimensional coupled vortex-induced vibration testing device for a suspended tunnel is used. The device includes a suspended tunnel truncated model (9), a boundary simulator, a wave generator and a current generator (1), a target point, and a vision capture device. Vertically arranged springs (12) are connected to the upper and lower ends of the suspended tunnel truncated model (9), and horizontally arranged springs (12) are connected to the left and right ends of the suspended tunnel truncated model (9). The boundary simulator constrains the boundary of the suspended tunnel truncated model (9), allowing the suspended tunnel truncated model (9) to vibrate freely within the boundary. The boundary simulator includes two opposing... The frame (10) is set at both ends of the suspended tunnel truncated model (9). The other end of the spring (12) is slidably connected to the corresponding frame (10). The other end of the vertically set spring (12) slides horizontally, and the other end of the horizontally set spring (12) slides vertically. The wave generator and the flow generator (1) generate waves and water flow that act on the suspended tunnel truncated model (9). The target points include several, which are respectively set on the suspended tunnel truncated model (9) and the boundary simulator. The visual capture device captures the coordinate position of the target points. The method includes the following steps: S1. The boundary of the suspended tunnel truncated model (9) is simulated using a spring (12) and a damper. The damper is a sliding damper. The elastic coefficient of the spring (12) is measured. S2. Allow the suspended tunnel truncated model (9) to undergo free decay vibration, and use a computer program to calculate the natural frequency and damping of the suspended tunnel truncated model (9) in the water using a non-contact visual measurement method. S3. Apply waves and water flow to the suspended tunnel truncated model (9), and use a computer program to calculate the elongation of the spring (12) through a non-contact visual measurement method, calculate the force on each spring (12), and decompose the force on the spring (12) in the direction of lift and resistance through the rotation angle of the spring (12), that is, calculate the constraint force of the boundary on the suspended tunnel truncated model (9). S4. Using a non-contact visual measurement method, the displacement of the suspended tunnel truncated model (9) is calculated by a computer program to obtain the vortex-induced dynamic response of the suspended tunnel truncated model (9), including the sway, heave and roll of the suspended tunnel truncated model (9), and the dimensionless displacement of the suspended tunnel truncated model (9) under different reduced velocities is calculated. S5. Using the constraint force of the boundary and the inertial force of the suspended tunnel truncated model (9), the vortex-induced vibration lift, drag and torque of the suspended tunnel truncated model (9) are calculated.

2. The vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels according to claim 1, characterized in that, Execute step S4 first, then step S3, or execute steps S3 and S4 simultaneously.

3. The vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels according to claim 1, characterized in that, The other end of the spring (12) is connected to a slide rail (11), which is slidably connected to the frame (10).

4. The vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels according to claim 1, characterized in that, The target points include spring target points (13), large target points (14) and small target points (15). Among the four springs (12) connected to one of the frames (10), each spring (12) is connected to the spring target point (13) at both ends. The large target point (14) is set at the center of the end face of the corresponding suspended tunnel cut-off model (9), and the small target point (15) is set at the midpoint of the radius.

5. The vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels according to claim 1, characterized in that, The vision capture device is a binocular camera (8).

6. The vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels according to any one of claims 1-5, characterized in that, It also includes a wave-flow water tank, one end of which is provided with the wave generator and the current generator (1), the boundary simulator and the suspended tunnel truncation model (9) are submerged in the water of the wave-flow water tank, and a transparent wall window is provided on one side wall of the wave-flow water tank, and the visual capture device is facing the target point through the transparent wall window.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels as described in any one of claims 1-6.

8. An electronic device, characterized in that, include: A memory on which computer programs are stored; A processor for executing the program in the memory to implement the vision-based two-dimensional coupled vortex-induced vibration testing method for suspended tunnels as described in any one of claims 1-6.

Images