CN103114659A

CN103114659A - Vortex induced vibration method of subduction tower type construction

Info

Publication number: CN103114659A
Application number: CN2013100516010A
Authority: CN
Inventors: 邵传平
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2013-01-29
Filing date: 2013-01-29
Publication date: 2013-05-22
Anticipated expiration: 2033-01-29
Also published as: CN103114659B

Abstract

The invention discloses a vortex induced vibration method of a subduction tower type construction, eight pairs of rotary supporting rods and eight strips of cloth are arranged on the upper end and lower end of the tower type construction, the eight supporting rods (2) on the upper end are arranged in the shape of a Chinese character 'mi', namely included angles between adjacent two supporting rods are 45 degrees, the eight supporting rods (2) on the lower end are also arranged in a shaped of Chinese character 'mi', namely included angles between adjacent two supporting rods are 45 degrees, and each pair of two upper and lower supporting rods are located at the same vertical surface; stripes of cloth on one to three supporting rods which have a minus 45 degrees to a positive 45 degrees with a wind direction included angle are selected to lift as windy weather; at the premise of not changing structural basic shape, the vortex induced vibration method of the subduction tower type construction has the advantages of applying an easy, feasible and effective method to control and prevent a vortex from falling off, and achieving the purpose of vortex induced vibration.

Description

A kind of method of subduing tower building vortex-induced vibration

Technical field

The present invention relates to build the weakening technical field, in particular a kind of method of subduing tower building vortex-induced vibration.

Background technology

When fluid is walked around the blunt form building with certain speed, can produce flow separation, at building both sides formation Vortex Shedding alternately, cause the pressure distribution generating period of building surface to sexually revise, thereby form alternating force and act on building, cause vibration of building, cause the fatigue damage of building structure and resident staff uncomfortable etc.The change frequency of alternating force is directly proportional to speed of incoming flow, is inversely proportional to the building breadth wise dimension.When the alternating force frequency is close with the building intrinsic frequency, can form resonance, safety of building is threatened.For cylindrical constructions such as TV transmission tower, power plant cooling towers, and the Rectangle building such as skyscraper, when strong wind was walked around, wind load was large, and vibration is strong, the weakening of need to taking measures.

The method that solves rotunda vortex-induced vibration problem on engineering can be divided into two classes: the first kind is the oscillatory property of change structure itself, as increasing the rigidity of structure, changes its intrinsic frequency to avoid resonance; If water tank, add counterweight, establish pendulum system etc., to strengthen damping; Adopt active and the vibration of passive control system control structure etc.Equations of The Second Kind is the flow dynamic characteristic of change structure, as airflow design, adopt the flow separation control device, adopt Vortex Shedding control method etc., eliminating or to weaken the formation of building downstream vortex, thereby eliminates or weakens vortex-induced vibration.Existing Vortex Shedding control method, also can be divided into two classes: 1) ACTIVE CONTROL needs the external energy driving control device, as jet, the micro breadth oscillation of cylinder own, damaged surface heating etc., 2) Passive Control does not need external energy to drive, division board as shown in Figure 1, rib etc. method ^[1]In existing passive control methods, control device all is attached on cylinder, or is connected with cylinder.

Document has been put down in writing a kind of little control member method recently ^[2], also belonging to Passive Control, its control member and cylinder are separated by a distance, and both are highly close, and the placement that is parallel to each other, and control member can be circular cross-section, can be also square or square-section, and the control member breadth wise dimension is much smaller than cylinder diameter.This control member method also is divided into two classes: a) control member is positioned at the cylinder upstream, and b) control member is positioned at the cylinder downstream.When control member was positioned at the upstream, control member can only be placed near the cylinder dead ahead, and namely the deviation in control member and cylinder dead ahead can not be greater than 3 °.Otherwise poor effect.Control member is positioned at the downstream, only has at present the result of study of circular control member.These results prove, only have when Reynolds number lower than 150 the time, and the effect of controlling Vortex Shedding is just arranged.And the Reynolds number of the buildings such as TV transmission tower often reaches 10 ⁶～10 ⁷Magnitude can not adopt.

List of references:

[1]Kumar?RA，Sohn?CH，Gowda?BHL，2008.Passive?Control?of?Vortex-Induced?Vibrations：An?Overview，Recent?Patents?on?Mechanical?Engineering，1：1-11.

[2]Prasad?A，williamson?CHK，1997.A?method?for?the?reduction?of?bluff?body?drag，Journal?of?Wind?Engineering?and?Industrial?Aerodynamics，69-71：155-167.

[3]Strykowski?PJ，Sreenivasan?KR，1990.On?the?formation?and?suppression?of?vortex?shedding?at?low?Reynolds?numbers，Journal?of?Fluid?Mechanics，218：71-107.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of method of subduing tower building vortex-induced vibration for the deficiencies in the prior art.

Technical scheme of the present invention is as follows:

A kind of method of subduing tower building vortex-induced vibration, the upper/lower terminal of tower building arranges eight pairs of rotatable poles and eight cloths, eight poles (2) of upper end become the rice font to arrange, be that angle between adjacent two poles is 45 degree, eight poles (2) of lower end also become the rice font to arrange, be that angle between adjacent two poles is 45 degree, every two poles in a pair of up and down (2) are positioned at same vertical plane; The pole of every a pair of upper and lower corresponding (2) plays a part ascending, descending and supports cloth (3); When wind is arranged, selection and wind direction angle are that-45 degree to the cloth on one to three pole between+45 degree rises; The pole of upper end (2) is by the motor-driven rotation, and on pole, around pull rope (6), pull rope (6) is used for the lifting of traction cloth (3); The face of each cloth (3) is parallel with the pole direction that supports it; The cloth plane is parallel with the tower building axis; The cloth width is b, and the average diameter of tower building is D, and the distance between cloth center line and tower building axis is G, and the spacing G/D of cloth and TV transmission tower axis should be chosen between 0.75-1.35; The cloth width is selected between b/D=0.15-0.25.

Adopt method of the present invention, under the prerequisite of change structure basic configuration not, adopt simple, easily row, and effective method to control Vortex Shedding processed, reach the purpose of subduing vortex-induced vibration.

Description of drawings

Fig. 1 is cloth and the scheme of installation (elevation) thereof of subduing vortex-induced vibration,

Fig. 2 is cloth and the scheme of installation (top view) thereof of subduing vortex-induced vibration

Fig. 3 is the A-A sectional drawing in Fig. 1;

Fig. 4 is the lifting schematic diagram of subduing the cloth of vortex-induced vibration;

Fig. 5 is that cloth is to the control effect of Vortex Shedding;

The cloth band of position (effectively district) of Fig. 6 for can effectively suppress Vortex Shedding in various Reynolds number situations, the cloth width is b/D=0.18;

The cloth band of position (effectively district) of Fig. 7 for can effectively suppress Vortex Shedding under various cloth width, Re=8 * 10 ⁴:

Fig. 8 is three kinds of control members (little square column, narrow cloth, small column have identical scale ratio b/D=0.24) when being positioned at the cylinder downstream, and cylinder is average and pulsation rises, resistance is with the variation of azimuthal angle beta; A, on the impact of fluctuating lift coefficient root-mean-square value; B, on the impact of pulsation resistance coefficient root-mean-square value; C, on the impact of average resistance coefficient; The impact of d on average lift coefficient.

1 revolving restaurant, 2 poles, 3 cloths, 4 TV transmission tower main bodys, 5 fixed trays, 6 pull ropes;

The specific embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.

As Figure 1-3, be TV transmission tower in tower building the present embodiment, the upper/lower terminal of TV transmission tower main body 4 arranges eight pairs of rotatable poles and eight cloths (bar), on eight poles 2, cloth 3 and lifting gear thereof are set all, 2 one-tenth rice fonts layouts of eight poles of upper end, namely the angle between adjacent two poles is 45 degree, eight poles 2 of lower end also become the rice font to arrange, be that angle between adjacent two poles is 45 degree, every two of a pair of up and down pole 2 is positioned at same vertical plane.The pole 2 of every a pair of upper and lower corresponding plays a part ascending, descending and supports cloth 3.When wind is arranged, selection and wind direction angle are that-45 degree to the cloth on one to three pole between+45 degree rises.As Fig. 4, the pole 2 of upper end is by the motor-driven rotation, and on pole, around pull rope 6, pull rope 6 is used for 3 liftings of traction cloth.The face of each cloth 3 is parallel with the pole direction that supports it.The pole 2 of lower end is wrapping up in the cloth of rolling.When motor started, pull rope 6 drove cloth 3 and rises or fall.

What vortex-induced vibration was played consumption is cloth, and its length is identical with the TV transmission tower body height, and the ratio b/D of width b and TV transmission tower average diameter D is determined by experiment.The ratio G/D apart from G and diameter D between cloth center line and TV transmission tower axis is determined by experiment.

The Aerodynamics Model of TV transmission tower and control member as shown in Figure 3, we have carried out experimental study, Fig. 5 is the FLOW VISUALIZATION experimental result: cloth width b/D=0.18, cloth and column axis be apart from G/D=1.2, reynolds number Re=V _∞D/v=10 ⁴, V wherein _∞Be speed of incoming flow, D is column diameter, and v is air movement viscosity; A, the vortex during without cloth is strong; B, cloth and incoming flow angle 30 degree, absence of vortices; C, cloth and incoming flow angle 45 degree, absence of vortices; D, cloth and incoming flow angle 55 degree, absence of vortices; Show that Vortex Shedding is not strong when there is no cloth, and when the placement cloth is in one is effectively distinguished, can suppress the generation of Vortex Shedding.Fig. 6 is that the width that experiment obtains is the effective district of cloth under different Reynolds number of b/D=0.18.Fig. 7 is effective district of testing the different in width cloth that obtains.Fig. 8 be cloth and other control members (spacing G fixes, when position angle β changes) suppress pulsation and the time equal aerodynamic force effect compare; Can find out, the inhibition of narrow cloth is best.

according to above experiment, determine: 1) the cloth plane is parallel with the TV transmission tower axis, 2) when wind is arranged, only hang a cloth at every turn, this hangs the cloth surface and the incoming flow angle should be near+45 degree or-45 degree, as: when blowing positive south wind, hang northwest to cloth 3 (cloth plane with incoming flow in angle of 45 degrees) or the cloth 3 of northeastward (cloth plane become-45 degree angles with incoming flow), or hang simultaneously this two cloths 3, when north wind blows, hang the southeast (with incoming flow in angle of 45 degrees) or the cloth 3 of southwestward (becomes with incoming flow-45 spend angles), 3) hang simultaneously three cloths 3, effect is better, during as north wind, can hang south (becoming 0 degree angle with incoming flow), the southeast (with incoming flow in angle of 45 degrees), three, southwest (becoming-45 degree angles with incoming flow) cloth 3, wherein become the cloth of 0 degree angle itself to reducing not contribution of vortex-induced vibration with incoming flow, but it plays a part the stable vibrating effect that suppresses, when wind direction changes, but excursion-45 the degree to+45 the degree within the time, can change the cloth that hangs, the effect that suppresses vibration is arranged equally, save the trouble of cloth descending operation and avoided cloth to change the risk that suppresses inefficacy between buck stay, 4) the spacing G/D of cloth and TV transmission tower axis should be chosen between 0.75-1.35, 5) the cloth width is selected between b/D=0.15-0.25.

Should be understood that, for those of ordinary skills, can be improved according to the above description or conversion, and all these improve and conversion all should belong to the protection domain of claims of the present invention.

Claims

1. method of subduing tower building vortex-induced vibration, it is characterized in that, the upper/lower terminal of tower building arranges eight pairs of rotatable poles and eight cloths, eight poles (2) of upper end become the rice font to arrange, be that angle between adjacent two poles is 45 degree, eight poles (2) of lower end also become the rice font to arrange, namely the angle between adjacent two poles is 45 degree, and every two poles in a pair of up and down (2) are positioned at same vertical plane; The pole of every a pair of upper and lower corresponding (2) plays a part ascending, descending and supports cloth (3); When wind is arranged, selection and wind direction angle are that-45 degree to the cloth on one to three pole between+45 degree rises; The pole of upper end (2) is by the motor-driven rotation, and on pole, around pull rope (6), pull rope (6) is used for the lifting of traction cloth (3); The face of each cloth (3) is parallel with the pole direction that supports it; The cloth plane is parallel with the tower building axis; The cloth width is b, and the average diameter of tower building is D, and the distance between cloth center line and tower building axis is G, and the spacing G/D of cloth and TV transmission tower axis should be chosen between 0.75-1.35; The cloth width is selected between b/D=0.15-0.25.