CN114369995A

CN114369995A - Flexible vortex generator for inhibiting bridge vortex vibration

Info

Publication number: CN114369995A
Application number: CN202210157954.8A
Authority: CN
Inventors: 尹亚鹏; 王汉封; 赵崇宇; 刘治威
Original assignee: Central South University; National Engineering Laboratory for High Speed Railway Construction Technology
Current assignee: Central South University; National Engineering Laboratory for High Speed Railway Construction Technology
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2022-04-19
Anticipated expiration: 2042-02-21
Also published as: WO2023155922A1; CN114369995B

Abstract

The invention discloses a flexible vortex generator for inhibiting bridge vortex vibration, which comprises a fixed base and a clamping sleeve arranged on the fixed base, wherein a flexible part is arranged on the clamping sleeve, one end of the flexible part is detachably connected with the clamping sleeve, and the other end of the flexible part is a free end and can freely swing along with wind. The flexible vortex generator does not need any external energy input, does not need to change the existing bridge device, only utilizes the self-adaptive deformation of the flexible part, induces a series of vortices through the flapping of the flexible structure, changes the flow form on the surface of the bridge, enhances the wind resistance of the bridge, and obviously inhibits the vortex vibration phenomenon of the bridge.

Description

Flexible vortex generator for inhibiting bridge vortex vibration

Technical Field

The invention relates to the technical field of bridge auxiliary equipment, in particular to a flexible vortex generator for inhibiting bridge vortex vibration.

Background

The phenomenon of wind-induced vibration of bridges is always a hotspot and difficult problem in the field of bridge engineering, such as vortex-induced vibration of a Tiger gate bridge. The control measures commonly used to suppress bridge vortex vibration at present include active control methods (requiring external energy input) and passive control methods (requiring no external energy input). The active control method mainly comprises the following steps: the wake vortex shedding is controlled by generating secondary flows to suppress vortex-induced vibration, the hydrodynamic viscosity and density are changed by thermal effects to affect boundary layer separation, and the like. The passive control method mainly comprises the following steps: changing the surface roughness to affect the boundary layer velocity profile to control boundary layer separation points, changing local contours (fairing addition, wall grooving, wind barrier arrangement, corner treatment, etc.) to affect flow separation reattachment, etc.

However, the above control methods have many problems and disadvantages. The active control method requires external energy input, which often causes inconvenience to the engineering and creates a problem of insufficient energy supply. Passive control methods, which are effective only within a certain wind speed or angle of attack, deteriorate the wind resistance once outside their optimal use range.

Therefore, it is an urgent need to develop a new auxiliary device for suppressing vortex vibration.

Disclosure of Invention

The invention aims to solve the problems that the bridge structure has large amplitude vibration and the bridge vortex vibration phenomenon is generated due to poor wind resistance of the bridge in the prior art, and provides a flexible vortex generator for inhibiting the bridge vortex vibration.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the utility model provides a restrain flexible vortex generator that bridge whirlpool shakes, includes fixed baseplate and the cutting ferrule of setting on fixed baseplate, be provided with the flexible piece on the cutting ferrule, flexible piece one end can be dismantled with the cutting ferrule and be connected, and the other end is the free end.

Preferably, the flexible member is made of a flexible material.

Preferably, the flexible member is a light flexible film structure with a smooth surface.

Preferably, the flexible member is a polyethylene film.

Preferably, the flexible member is of a graded thickness.

Preferably, the surface of the flexible piece is provided with a plurality of ventilation holes.

Preferably, the free end of the flexible part is provided with edge teeth, and the tooth-shaped structure of the edge teeth is in a shape of a buttress, a triangle, a convex circle or a concave circle.

Further preferably, the ferrule comprises two magnetic connectors symmetrically arranged on the fixed base, and the two magnetic connectors are magnetically connected with the fixed base; the two magnetic connectors are magnetically connected, and one end of the flexible part is clamped between the two magnetic connectors to be fixed.

Further preferably, the fixing base is in a hoop shape, a square shape or a weight shape.

When fluid flows through the bridge structure, flow separation occurs at sharp positions on the surface of the structure to form a shear layer, and periodic vortex shedding can be formed after the shear layer is shed. When the vortex shedding frequency is close to the modal frequency of a certain order of the bridge structure, the bridge structure can vibrate to a larger extent, namely, the bridge vortex vibration phenomenon is generated. Therefore, the vortex shedding on the surface of the bridge structure is inhibited, and the key factor for controlling the vortex vibration of the bridge is achieved.

According to the invention, a series of vortexes are induced by flapping of the flexible structure by utilizing the self-adaptive deformation of the flexible film structure of the flexible part, so that the flow form of the surface of the bridge is changed, the wind resistance of the bridge is enhanced, and the vortex vibration phenomenon of the bridge is inhibited. The flexible vortex generator is detachably arranged on a bridge rail or a bridge surface, the installation included angle between the flexible vortex generator and the horizontal plane is 0-90 degrees, a flexible piece on the flexible vortex generator is of a flexible film structure with a smooth surface, and when fluid flows through the flexible film, the flexible film can generate 5 motion forms such as stable deformation, slight swinging of a tip part, large-amplitude swinging of a middle upper part, overall violent flapping, flapping and wall collision (or inner rolling) according to the difference of fluid speeds. When the flexible film enters a stable deformation stage, the free end of the flexible film only generates a shear layer without vortex shedding, which is equivalent to moving a fluid separation point to the outside of the structure, and the interference effect on the flow is weak. When the flexible film enters a swinging or flapping stage, momentum exchange between airflow outside the bridge structure and airflow on the surface of the structure can be enhanced, separation of airflow on the surface of the bridge structure is inhibited, the original vortex shedding form is changed, wind resistance stability of the bridge structure is enhanced, and the vortex vibration phenomenon of the bridge is inhibited.

Especially when the film flapping frequency is synchronous with the vortex shedding frequency, the momentum exchange effect is the best. However, the influence area of the film is limited, the momentum exchange effect of the area close to the film is good, and the momentum exchange effect of the area far away from the film is fast attenuated, so that flexible films are preferably arranged in sequence at proper intervals in the flow direction, namely, a plurality of rows of flexible vortex generators in the invention can be arranged side by side, so that the momentum exchange effect can be continuously enhanced in the flow direction, and the problem of insufficient influence area of a single row of film is solved.

The invention has the following beneficial effects:

the flexible vortex generator does not need any external energy input, does not need to change the existing bridge device, only utilizes the self-adaptive deformation of the flexible part, induces a series of vortices through the flapping of the flexible structure, changes the flow form of the surface of the bridge, enhances the wind resistance of the bridge, and obviously inhibits the vortex vibration phenomenon of the bridge;

secondly), the flexible part in the invention adopts thickness change or adopts different edge tooth structures at the free end, and can generate self-adaptive deformation according to different wind environments, thereby more accurately generating flapping forms, inhibiting the phenomenon of bridge vortex vibration and having very wide application range;

thirdly), the flexible vortex generator in the invention has simple structure, convenient replacement, easy disassembly and convenient daily maintenance, avoids various maintenance works with complicated operation and saves manpower and material resources.

Drawings

FIG. 1 is a schematic structural diagram of a flexible vortex generator according to embodiment 1 of the present invention;

fig. 2 is a schematic structural view of a square fixing base in embodiment 2 of the present invention;

fig. 3 is a schematic structural view of a weight-shaped fixing base in embodiment 3 of the present invention;

fig. 4 is a schematic structural view of a triangular edge tooth in embodiment 4 of the present invention.

In the figure: 1-fixed base, 2-magnetic connecting piece, 3-flexible piece, 4-ventilation hole and 5-edge tooth.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

Example 1

As shown in FIG. 1, a flexible vortex generator for restraining bridge vortex vibration is installed on a bridge railing and comprises a fixed base 1 and a clamping sleeve arranged on the fixed base 1, wherein the fixed base 1 is in a clamping hoop shape and is clamped with a circular railing of the bridge to facilitate disassembly. The cutting sleeve comprises two magnetic connectors 2, the two magnetic connectors 2 are symmetrically arranged on a fixed base 1, and the two magnetic connectors 2 are magnetically connected with the fixed base 1; the two magnetic connectors 2 are connected in a magnetic mode, one end of the flexible part 3 is clamped between the two magnetic connectors 2 to be fixed, and the other end of the flexible part 3 is a free end and can swing freely along with wind. The invention has simple structure, convenient replacement, easy disassembly and convenient daily maintenance, avoids various maintenance works with complicated operation and saves manpower and material resources.

The flexible member 3 is a light flexible film structure with a smooth surface and no wrinkles, in the embodiment, the flexible member 3 is a rectangular polyethylene film, the thickness of the flexible member is gradually changed, the length-width ratio of the flexible member is 1.5, a plurality of ventilation holes 4 are dispersedly formed in the surface of the flexible member 3, meanwhile, the free end of the flexible member 3 is provided with edge teeth 5, and the tooth-shaped structure of the edge teeth 5 is in a shape of a battlement. The flexible part 3 made of the material and the structure can generate self-adaptive deformation in a wind environment, a series of vortexes are induced by flapping of the flexible structure, the flow form of the surface of the bridge is changed, the wind resistance of the bridge is enhanced, and the vortex vibration phenomenon of the bridge is inhibited.

During the specific use, with flexible vortex generator's fixed baseplate 1 joint to the circular railing of bridge on, with the one end centre gripping of flexible piece 3 between two magnetic connecting piece 2 of cutting ferrule, the contained angle of adjustment between flexible vortex generator and the horizontal plane is 45 degrees. When the airflow passes through the flexible part 3 of the flexible vortex generator, the flexible part 3 enters a swinging or flapping stage, momentum exchange between the airflow outside the bridge structure and the airflow on the surface of the structure is enhanced, separation of the airflow on the surface of the bridge structure is inhibited, the original vortex shedding form is changed, the wind resistance stability of the bridge structure is enhanced, and therefore the phenomenon of bridge vortex vibration is obviously inhibited. In the embodiment, an acceleration sensor is further arranged in the fixed base 1 and used for detecting the vibration condition of the bridge deck and feeding back the vibration suppression effect in real time.

Example 2

On the basis of the embodiment 1, as shown in fig. 2, the fixing base 1 of the embodiment is square, and is clamped with the square rail of the bridge, and the flexible vortex generator can be installed in parallel with the horizontal plane.

Example 3

On the basis of the embodiment 1, as shown in fig. 3, the fixed base 1 of the embodiment is in a weight shape, and can be directly placed on a construction bridge floor, and the flexible vortex generator is placed perpendicular to a horizontal plane.

Example 4

Based on the embodiment 1, as shown in fig. 4, the tooth-like structure of the edge teeth 5 at the free end of the flexible member 3 in this embodiment is triangular.

The present specification and figures are to be regarded as illustrative rather than restrictive, and it is intended that all such alterations and modifications that fall within the true spirit and scope of the invention, and that all such modifications and variations are included within the scope of the invention as determined by the appended claims without the use of inventive faculty.

Claims

1. The utility model provides a restrain flexible vortex generator that bridge whirlpool shakes which characterized in that, includes fixed baseplate and the cutting ferrule of setting on fixed baseplate, be provided with the flexible piece on the cutting ferrule, flexible piece one end can be dismantled with the cutting ferrule and be connected, and the other end is the free end.

2. The flexible vortex generator of claim 1, wherein the flexible member is constructed of a flexible material.

3. The flexible vortex generator of claim 2, wherein the flexible member is a smooth surfaced lightweight flexible film structure.

4. The flexible vortex generator of claim 3, wherein the flexible member is a polyethylene film.

5. The flexible vortex generator of claim 3, wherein the flexible member is of a graded thickness.

6. The flexible vortex generator of claim 3, wherein the flexible member surface is provided with a plurality of ventilation holes.

7. The flexible vortex generator according to claim 1, wherein the free end of the flexible member is provided with edge teeth, the tooth-like structure of which is castellated, triangular, convex circular or concave circular.

8. The flexible vortex generator according to claim 1, wherein the ferrule comprises two magnetic connectors symmetrically disposed on the fixed base, the two magnetic connectors magnetically connected to the fixed base; the two magnetic connecting pieces are magnetically connected, and one end of the flexible piece is clamped between the two magnetic connecting pieces to be fixed.

9. The flexible vortex generator according to claim 1, wherein the fixed base is collar-shaped, square-shaped or weight-shaped.