Suspension tunnel vortex-induced vibration suppression method based on rotary nonlinear damper

Abstract

The invention belongs to the field of suppression of vortex-induced vibration of a floating tunnel, and discloses a method for suppressing vortex-induced vibration of a floating tunnel based on a rotary nonlinear damper. According to the method, suppression measures are taken for the vortex-induced vibration problem of the floating tunnel, the rotary nonlinear damper is applied to the floating tunnel, energy generated by vortex-induced vibration of the floating tunnel is absorbed and dissipated, and therefore the purpose of weakening the vortex-induced vibration of the floating tunnel is achieved. According to the method, the problems of tunnel structure deformation and fatigue failure caused by the vortex-induced vibration of the floating tunnel can be effectively avoided, and the vortex-induced vibration of the floating tunnel is effectively inhibited. The rotary nonlinear damper has a wider damping frequency band and better robustness, can be flexibly applied to complex sea conditions, greatly saves the construction cost of the floating tunnel, greatly reduces the construction cost, and creates good social and economic values.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vortex-induced vibration suppression of a suspended tunnel, and relates to a vortex-induced vibration suppression method for a suspended tunnel based on a rotary nonlinear vibration absorber (RNVA). BACKGROUND

[0002] With the continuous development of marine engineering technology, the marine suspended tunnel, as an innovative transportation structure, shows broad application prospects. Especially in areas that need to cross vast waters, the suspended tunnel will become an important transportation solution. The core goal of the suspended tunnel structure design is to avoid the outstanding problems of traditional submarine tunnels in complex geological conditions, construction difficulty, and ecological environment impact. Unlike traditional submarine tunnels, the suspended tunnel adopts a suspended structure design, with the buoyancy provided by the floating body component supporting the tunnel pipe body, so that the pipe body is suspended in the ocean. This design mainly relies on the floating body structure and uses buoyancy to support the tunnel pipe body, greatly reducing the direct dependence on the complex seabed geology. This design not only helps to simplify the construction process and reduce engineering construction costs, but also improves the overall anti-interference ability and operational stability of the structure.

[0003] The suspended tunnel pipe body is suspended in the ocean and is prone to vortex-induced vibration under the action of fluid. When the natural frequency of the suspended tunnel structure is close to the vortex shedding frequency, the "lock-in" phenomenon occurs, and the vibration amplitude of the suspended tunnel increases significantly, which can easily cause deformation and fatigue failure of the tunnel structure, affecting the safety and stability of the project. Therefore, the research on the vibration reduction technology for vortex-induced vibration of the suspended tunnel has important engineering significance for ensuring its long-term safe and stable operation.

[0004] The suspended tunnel tube has a cylindrical structure, and the suspended tunnel can be simplified into a cylindrical model for related research. According to the vibration control principle, the realization of cylindrical vortex-induced vibration reduction technology mainly considers the following two aspects: First, by changing the conditions for vortex generation and the wake flow state, the lift and drag forces of the fluid acting on the cylindrical structure can be reduced. Second, by adjusting the dynamic characteristics of the structure itself, the vortex-induced vibration response of the cylinder can be reduced. See "Chen, SS (author), Feng Zhenyu, Zhang Xinong (translator). (1993). Flow-induced vibration of cylindrical structures". The working principle of the rotary nonlinear vibration damper (RNVA) is as follows: the mass block in the RNVA rotates around the axis of the main structure with a fixed radius, and can be freely adjusted at any frequency, thereby inertially coupling with any vibration mode of the main structure, absorbing and dissipating the vibration energy of the main structure, and achieving the purpose of vibration reduction. In their paper "Effect of an internal nonlinear rotational dissipative element on vortex shedding and vortex-induced vibration of a sprung circular cylinder," Tumkur et al. applied this type of nonlinear vibration damper to the suppression of vortex-induced vibration in the transverse flow of a cylinder. Their study found that the RNVA (Rotational Nonlinear Vibration Damper) achieved a vibration reduction efficiency of up to 78% in the amplitude of vortex-induced vibration of the cylinder, while significantly extending the wake region connected to the cylinder. Based on these principles, the RNVA can be applied to suspended tunnels. By effectively absorbing and dissipating the energy generated by vortex-induced vibration in the suspended tunnel, the RNVA can weaken the vortex-induced vibration response of the suspended tunnel. Summary of the Invention

[0005] To address the problem of vortex-induced vibration in suspended tunnels and to provide a scientific basis and technical support for the design and construction of suspended tunnels, the objective of this invention is to provide a method for suppressing vortex-induced vibration in suspended tunnels based on a rotating nonlinear vibration damper (RNVA), thereby providing a reliable guarantee for the safe operation of suspended tunnels.

[0006] The technical solution of the present invention:

[0007] A method for suppressing vortex-induced vibration in a suspended tunnel based on a rotating nonlinear vibration damper includes the following steps:

[0008] (1) Determine the range of occurrence of vortex-induced vibration in the suspended tunnel;

[0009] The occurrence range of vortex-induced vibration in suspended tunnels is jointly determined by structural characteristics, fluid flow state, and vortex shedding frequency. Structural characteristics include structural mass, stiffness, and damping; fluid flow state includes laminar and turbulent flow; and the vortex shedding frequency is the St number. The St number changes with the fluid flow state, and when it approaches the natural frequency of the suspended tunnel structure, a "lock-in" phenomenon occurs, leading to a significant increase in the amplitude of vortex-induced vibration. Numerical simulation is a commonly used technique for studying vortex-induced vibration in engineering structures. By adjusting the parameters of the numerical model, the vortex-induced vibration of the structure under different flow states can be accurately simulated to obtain the vortex-induced vibration response of the structure. To verify the method proposed in this invention of using a rotating nonlinear vibration damper to suppress vortex-induced vibration in suspended tunnels... To assess its effectiveness, this invention employs numerical simulation methods for analysis. Based on the structural characteristics of the suspended tunnel, a fluid-structure interaction numerical model of the suspended tunnel is established. This model is used to simulate the vortex-induced vibration response of the suspended tunnel under different flow conditions, thus determining the occurrence range of vortex-induced vibration. Firstly, this invention numerically simulates the vortex-induced vibration response of a suspended tunnel without a rotating nonlinear damper under different flow conditions, obtaining the relationship between the amplitude of the vortex-induced vibration and the dimensionless parameter Ury. When the dimensionless parameter Ury is in the range of 3.3 ≤ Ury ≤ 8.0, the suspended tunnel exhibits a "lock-in" phenomenon, and the amplitude of the vortex-induced vibration significantly increases. Therefore, this range is determined as the occurrence range of vortex-induced vibration in the suspended tunnel. Here, Ury is the reduced velocity, representing the fluid flow state.

[0010] (2) Determine the relationship between the control parameters of the rotating nonlinear vibration damper and the vortex-induced vibration of the suspended tunnel;

[0011] The control parameters of a rotary nonlinear vibration damper include mass ratio ε, rotation radius r, and damping ratio ξ. r The relationship between the control parameters of the rotating nonlinear vibration damper and the vortex-induced vibration of the suspended tunnel is established to ensure that the selected control parameters effectively suppress the vortex-induced vibration of the suspended tunnel within the range of vortex-induced vibration occurrence.

[0012] Based on the fluid-structure interaction numerical model established in step (1), the mass ratio ε, rotation radius r, and damping ratio ξ are investigated using the controlled variable method. r The influence of three control parameters on the vortex-induced vibration response of a suspended tunnel was investigated, and the relationship between the control parameters of a rotating nonlinear vibration damper and the vortex-induced vibration response of a suspended tunnel was established.

[0013] Figure 1 The damping ratio ξ of the rotary nonlinear damper (RNVA) is shown. r Influence of damping ratio ξ on vortex-induced vibration of suspended tunnels: r With the increase of ξ, the amplitude of vortex-induced vibration in the suspended tunnel decreases significantly, and the amplitude decreases at the critical damping ratio ξ.r The vibration reduction efficiency reaches its peak at a point = 0.10, exceeding the critical damping ratio ξ. r Afterwards, although RNVA still has a certain vibration reduction effect, under certain flow conditions, the amplitude of vortex-induced vibration in the suspended tunnel shows a reverse increase. Figure 2 The effect of the rotation radius r of the rotating nonlinear vibration damper (RNVA) on the vortex-induced vibration of the suspended tunnel is shown: the vibration reduction efficiency of the RNVA increases with the increase of the rotation radius r, and reaches the peak at the critical rotation radius r=0.48. Thereafter, there is no reverse increase in the amplitude of vortex-induced vibration of the suspended tunnel. Figure 3 The effect of the mass ratio ε of the rotating nonlinear vibration damper (RNVA) on the vortex-induced vibration of a suspended tunnel is demonstrated: as the mass ratio ε increases, the amplitude of the vortex-induced vibration of the suspended tunnel gradually decreases, and the damping efficiency reaches its peak at the critical mass ratio ε = 0.5. After exceeding the critical mass ratio ε, although the RNVA still has a certain damping effect, under certain flow conditions, the amplitude of the vortex-induced vibration of the suspended tunnel shows a reverse increase.

[0014] Through the above numerical simulation analysis, this invention finally constructed the mass ratio ε, rotation radius r, and damping ratio ξ of the rotating nonlinear vibration damper (RNVA). r The relationship between the three control parameters and the vortex-induced vibration response of the suspended tunnel provides a basis for determining the optimal control parameters for the RNVA.

[0015] (3) Determination of optimal parameters for rotary nonlinear vibration damper;

[0016] The principle for selecting the optimal control parameters of the rotary nonlinear vibration damper is to ensure that the rotary nonlinear vibration damper has a stable and efficient vibration reduction effect in the vortex-induced vibration range of the suspended tunnel; among which, the stable and efficient vibration reduction effect requires that the selected parameters enable the rotary nonlinear vibration damper to achieve a vibration reduction efficiency of more than 20% under different flow conditions; based on the mass ratio ε, rotation radius r and damping ratio ξ of the rotary nonlinear vibration damper established in step (2) r The relationship with the vortex-induced vibration response of the suspended tunnel shows that each control parameter has a corresponding critical value, which makes the vibration reduction efficiency of the rotary nonlinear vibration damper optimal. The critical values ​​of each control parameter that make the vibration reduction efficiency of the rotary nonlinear vibration damper optimal are taken as the optimal control parameters of the rotary nonlinear vibration damper.

[0017] The beneficial effects of this invention are:

[0018] 1) Rotary nonlinear vibration damper (RNVA) can effectively suppress vortex-induced vibration of suspended tunnels, ensuring the safe operation of suspended tunnels;

[0019] 2) Rotary nonlinear vibration dampers (RNVA) have a wider vibration damping frequency band and better robustness, and can be flexibly applied to complex sea conditions. At the same time, they can significantly reduce the construction cost of suspended tunnels, greatly reduce the project cost, and create good social and economic value. Attached Figure Description

[0020] Figure 1 The variation of the transverse vibration amplitude of a cylinder with the reduced velocity of the cylinder under different RNVA damping ratios (r = 0.48, ε = 0.5).

[0021] Figure 2 The variation of the transverse vibration amplitude of a cylinder with the reduced velocity of the cylinder under different RNVA rotation radii (ξ) r =0.10, ε = 0.5).

[0022] Figure 3 The variation of the transverse vibration amplitude of a cylinder with the reduced velocity of the cylinder under different RNVA mass ratios (ξ) r =0.10, r = 0.48)

[0023] Figure 4 A schematic diagram of the transverse vortex-induced vibration model of a cylindrical-RNVA system;

[0024] Figure 5 Time history curves of lift coefficient and drag coefficient for flow around a fixed cylinder; where (a) is the time history curve of drag coefficient and (b) is the time history curve of lift coefficient.

[0025] Figure 6 A schematic diagram of the transverse vortex-induced vibration of the Tumkur et al. cylindrical-RNVA system;

[0026] Figure 7 The time history curves of transverse vibration displacement of the cylinder are compared with those of Tumkur et al.; where (a) is the time history curve of Tumkur et al. at r = 0.2, ξ r = 0.101, ε = 0.3. (b) shows the displacement-time history curve of the cylinder under the condition of r = 0.2, ξ. r = 0.101, ε = 0.3. (c) is the displacement-time history curve of the cylinder under the condition of r = 0.2, ξ = 0.3. r = 0.469, ε = 0.3. (d) The numerical model established in this invention at r = 0.2, ξ r = 0.469, ε = 0.3 Displacement time history curve of cylindrical vibration under the working condition;

[0027] Figure 8This is a schematic diagram of the computational domain for the transverse vortex-induced vibration of the cylindrical-RNVA system of the present invention under the action of water flow;

[0028] Figure 9 The time history curves of transverse vibration displacement of a cylinder under different reduced velocities (ξ) r = 0.10, r = 0.48, ε = 0.5); where (a) is Ury = 4.0, (b) is Ury = 5.0, (c) is Ury = 8.0, and (d) is Ury = 16.0. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0030] The numerical simulation method involved in this invention is as follows:

[0031] To facilitate numerical studies, the suspended tunnel tube is simplified as a cylinder, and the flow around a bluff body is simplified as the flow around a cylinder. This invention proposes using RNVA to control the vortex-induced vibration of a horizontal cylinder under low density ratio conditions. Figure 4 The diagram shows a schematic of the transverse vortex-induced vibration model of the cylindrical-RNVA system.

[0032] The fundamental governing equations for the motion of a uniform, incompressible viscous fluid are the continuity equation and the Navier-Stokes equation. From the ALE perspective, the dimensionless form of the governing equations is as follows:

[0033]

[0034]

[0035] The dimensionless equation of motion for the single-degree-of-freedom vortex-induced vibration of the cylindrical-RNVA system is as follows:

[0036]

[0037] First, numerical verification was performed on the flow around a fixed cylinder. Figure 5 This presents the time history curves of the drag force coefficient and lift coefficient of the fixed cylinder flow calculated according to this invention. The Strouhal number St and the mean drag force coefficient C of the cylinder under fluid action are also shown. D M Lift coefficient amplitude C L AAs shown in Table 1, the table includes previous calculation results. Table 1 demonstrates that the calculation results of the numerical model of this invention are in good agreement with previous research results, indicating that the fluid-structure interaction numerical model established in this invention has high computational accuracy in fluid calculations.

[0038] Table 1. Comparison of numerical simulation results of flow around a fixed cylinder with previous studies.

[0039]

[0040] This verification section uses the same system parameters as Tumkur et al. to conduct numerical verification. Figure 6 The diagram shown is a schematic of the Tumkur-equal cylindrical-RNVA system model. Figure 7 The figure shows a comparison between the time history curve of the cylindrical transverse vibration displacement and the results obtained by Tumkur et al. It can be seen that the time history curve of the cylindrical vibration displacement calculated by this invention has good consistency with the calculation results of Tumkur et al. According to the definition of Tumkur et al., the vibration reduction efficiency of RNVA is expressed as the percentage reduction in the root mean square value of the cylindrical displacement with RNVA compared to the root mean square value of the cylindrical displacement without RNVA within a time unit from 200 to 1000. Based on this calculation, the RNVA vibration reduction efficiencies of this invention and Tumkur et al. in operating condition (a) are 67% and 71%, respectively; the RNVA vibration reduction efficiencies of this invention and Tumkur et al. in operating condition (b) are 47% and 50%, respectively. This shows that the numerical calculation results of this invention are well compared with those of previous studies.

[0041] Figure 8 This is a diagram showing the layout of the computational domain for transverse vortex-induced vibration in a cylindrical-RNVA system. Figure 9 The following are given for the reduced velocities of some typical cylinders, with respect to ξ. r The displacement time history curves of the cylinder with and without RNVA are shown when r = 0.10, r = 0.48, and ε = 0.5. The black line represents the lateral displacement amplitude of the cylinder without RNVA, and the red line represents the lateral displacement time history curve with RNVA. It can be seen that the cylinder without RNVA experiences relatively large vibrations at Ury = 4.0 and 5.0, with amplitudes of 0.561 and 0.529, respectively. After installing RNVA, the cylinder amplitude is significantly reduced, decreasing to 0.426 and 0.306, respectively. The vibration reduction efficiency of RNVA is 24.1% and 42.2%, respectively, showing a significant vibration reduction effect. At Ury = 8.0, the cylinder exhibits irregular vibration. It can be observed that the cylinder amplitude decreases during the period when RNVA is rotating. At Ury = 16.0, RNVA mainly performs small-amplitude reciprocating motion and has almost no effect on controlling the cylinder vibration.

[0042] In summary, the effectiveness of the method of the present invention has been demonstrated, and it can be applied to engineering practice. RNVA has important reference significance and engineering value for suppressing vortex-induced vibration in suspended tunnels.

Claims

1. A method for suppressing vortex-induced vibration in a suspended tunnel based on a rotating nonlinear vibration damper, characterized in that, Includes the following steps: (1) Determine the range of occurrence of vortex-induced vibration in the suspended tunnel; The occurrence range of vortex-induced vibration in suspended tunnels is jointly determined by structural characteristics, fluid flow state, and vortex shedding frequency. Structural characteristics include structural mass, stiffness, and damping; fluid flow state includes laminar and turbulent flow; and the vortex shedding frequency is the St number. The St number changes with the fluid flow state, and when it approaches the natural frequency of the suspended tunnel, a "lock-in" phenomenon occurs, leading to a significant increase in the amplitude of vortex-induced vibration. Using numerical simulation methods, a fluid-structure interaction numerical model of the suspended tunnel is established based on its structural characteristics. Numerical models were used to simulate the vortex-induced vibration response of a suspended tunnel under different flow conditions to determine the occurrence range of vortex-induced vibration. Numerical simulations were also performed on the vortex-induced vibration response of a suspended tunnel without a rotating nonlinear damper under different flow conditions to obtain the relationship between the amplitude of the vortex-induced vibration and the dimensionless parameter Ury. When the dimensionless parameter Ury was in the range of 3.3≤Ury≤8.0, the suspended tunnel exhibited a "lock-in" phenomenon, and the amplitude of the vortex-induced vibration increased significantly. This range was thus determined as the occurrence range of vortex-induced vibration in the suspended tunnel. Here, Ury is the reduced velocity, representing the fluid flow state. (2) Determine the relationship between the control parameters of the rotating nonlinear vibration damper and the vortex-induced vibration of the suspended tunnel; The control parameters of a rotary nonlinear vibration damper include mass ratio ε, rotation radius r, and damping ratio ξ. r The relationship between the control parameters of the rotating nonlinear vibration damper and the vortex-induced vibration of the suspended tunnel is established to ensure that the selected control parameters effectively suppress the vortex-induced vibration of the suspended tunnel within the range of vortex-induced vibration occurrence. Based on the fluid-structure interaction numerical model established in step (1), the mass ratio ε, rotation radius r, and damping ratio ξ are investigated using the controlled variable method. r The influence of three control parameters on the vortex-induced vibration response of a suspended tunnel was investigated, and the relationship between the control parameters of a rotating nonlinear vibration damper and the vortex-induced vibration response of a suspended tunnel was established. (3) Determination of optimal parameters for rotary nonlinear vibration damper; The principle for selecting the optimal control parameters of the rotary nonlinear vibration damper is to ensure that the rotary nonlinear vibration damper has a stable and efficient vibration reduction effect in the vortex-induced vibration range of the suspended tunnel; among which, the stable and efficient vibration reduction effect requires that the selected parameters enable the rotary nonlinear vibration damper to achieve a vibration reduction efficiency of more than 20% under different flow conditions; based on the mass ratio ε, rotation radius r and damping ratio ξ of the rotary nonlinear vibration damper established in step (2) r The relationship with the vortex-induced vibration response of the suspended tunnel shows that each control parameter has a corresponding critical value, which makes the vibration reduction efficiency of the rotary nonlinear vibration damper optimal. The critical values ​​of each control parameter that make the vibration reduction efficiency of the rotary nonlinear vibration damper optimal are taken as the optimal control parameters of the rotary nonlinear vibration damper.

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