CN205153662U - Anti -current body vortex induced vibration's cylinder structure - Google Patents

Abstract

The utility model discloses an anti -current body vortex induced vibration's cylinder structure. The cylinder bottom mounting is on the base, and the cylinder is the polygon that shape of cross section is the same, the cylinder have arbitrary cross -section upwards to the top by the rotatory helical structure of formation of polygon. The utility model discloses fully realizing the sharp power dependence decay in cross -section whirlpool and being favorable to restraining the vortex induced vibration amplitude, become screw -tupe revolution mechanic with cross -section design, the purpose lets the sharp power dependence in whirlpool of structure attenuate as early as possible. Simultaneously, this kind of structural style has avoided adopting streamline structure only in the functional drawback of the anti vortex induced vibration of single direction, and the later stage need not basically to maintain the cost is reduced.

Description

A kind of column structure of resist fluids vortex-induced vibration

Technical field

The utility model belongs to anti-vibration column structure design field, particularly relates to a kind of column structure of resist fluids vortex-induced vibration, particularly a kind of column structure of wind resistance vortex-induced vibration.

Background technology

General support cylinder mostly is the column of cylinder or equilateral polygon section form, as lamppost, wind-power electricity generation support column, the column of this form of structure easily causes vortex-induced vibration at the lower generation fluid at strong fluid matasomatism, long-term vortex-induced vibration easily causes column structure fatigue failure, and the ancillary facility be arranged on cylinder damages inefficacy.Be arranged on the bulb premature breakdown on lamppost as caused, thus cause economic loss.Existing cylinder is square or circular cross-section cylinder, its vortex-induced vibration amplitude is larger, also there is the column structure changing positive 8 angle sections into, although the cylinder of this structure makes moderate progress than square column or the anti-vortex-induced vibration performance of column structure, but still do not reach satisfactory effect.

Summary of the invention

The utility model is for the deficiencies in the prior art, provides a kind of column structure of novel anti-vortex-induced vibration.Problem to be solved in the utility model is to provide a kind ofly improves the fluid vortex-induced vibration reducing further cylinder by column structure, to improve cylinder application life, avoid or reduce the damage of the ancillary facility on cylinder.

The utility model is achieved through the following technical solutions:

The column structure of resist fluids vortex-induced vibration, described cylinder bottom is fixed on pedestal, it is characterized in that: described cylinder is the polygon that shape of cross section is identical, and cylinder has arbitrary cross section upwards to form helical structure to top by polygon rotation.

The cross section of described cylinder is regular polygon.

Described cylinder is by bottom upwards or progressive reduction identical to top cross sectional area.

Described helical structure length is not less than 1/4th of cylinder length.

The utility model adopts the helical structure of following calculating formula determination cylinder further:

Wherein ρ, θ, H are respectively pole axis below cylindrical coordinate, corner, post high (axis of a cylinder to) three physical quantitys, and corresponding unit is respectively m, radian, m.

ρ ₀representing the maximum radius in cross section, is constant.H ₀for post is high

I is the gradient 0≤i<1 of the gabarit of cylinder, as shown in the figure i=tan (α), is constant dimension column as i=0.

describe cross-sectional shape change function under polar coordinate system, f (0)=1, but nonidentical in 1, be not namely circular cross-section; Namely with pole section maximum radius ρ ₀place sets up cylindrical coordinate, works as corner when being 0, pole section radius is maximum.As f (β again ₀)=1, the β that definition is corresponding ₀to attach most importance to complex phase parallactic angle, 0< β ₀≤ 2 π.

The utility model realizes suppressing vortex-induced vibration about structure generation vortex-induced vibration theory according to following:

Analyze from the angle of fluid, any blunt form section cylinder, under certain wind speed, all can produce alternating action in object both sides in the vortex on works surface, as accompanying drawing 1.The vortex of this alternating action will produce periodically variable pressure fluctuation meter to structure.Its acting frequency changes with the change of wind speed, if cylinder is the structure of elastic body or resiliency supported, when the eigentone that wind speed changes to swirling action frequency and structure close to time, will excitation structure generation Vortex-excited vibration, the whirlpool of rushing down that simultaneously regular structural vibration can change again its wake flow conversely produces locking phenomena.This fluid---works is interactional to be referred to as " vortex-induced vibration ".Vortex-induced vibration can cause the fatigue failure of structure, and the vortex-induced vibration crossing large amplitude even can affect the functional performance of structure.

Vortex-induced vibration meets Strouhal number (Strouhal) relation:

$St=\frac{f_{N}D}{U}---\left(1\right)$

In formula, St represents Strouhal number (Strouhalnumber), f _nfor whirlpool takes off frequency, D represents the lateral dimension of structure, and U is the incoming flow wind speed of uniform incoming flow.

From Strouhal number relation, cross sectional shape is certain, whirlpool takes off frequency and incoming flow wind speed is directly proportional, under the effect of gas bounce effect, although there is change in column structure cross section, but because the locking of power (lateral force) acting frequency passive movement is swashed in its whirlpool, result causes whirlpool to swash power frequency along cylinder axis to being consistent.

Represent that power is swashed in the horizontal whirlpool acting on cylinder with following experience linear model approx:

$f_L=\frac{1}{2}{\mathrm{\&rho;}}_a{U}^2{{\mathrm{DC}}^{\&prime;}}_L\left(H\right)sin\&lsqb;{\mathrm{\&omega;}}_{s}t+\mathrm{\&alpha;}\left(H\right)\&rsqb;---\left(2\right)$

Wherein, α (H) represents that power is swashed along cylinder axis to there is phase difference in whirlpool, hereinafter referred to as α; ρ _afor atmospheric density; U is incoming flow wind speed; ω _sfor vortex acting frequency; D cross section maximum size; C' _l(H) being parameter to be identified, is the function of cylinder axial coordinate H, hereinafter referred to as C' _l.

When lamppost generation vortex-induced vibration, only consider that power is swashed in the whirlpool of cylinder, ignores lamppost ancillary facility aerodynamic force, introduce mode factor:

y(H,t)＝φ(H)ξ(t)(3)

In formula, y (H, t) represents the vortex-induced vibration response of cylinder any position, and φ (H) is cylinder mode factor, hereinafter referred to as φ; ξ (H) is generalized coordinates.Because charming appearance and behaviour vortex-induced vibration is generally the vibration under single mode condition, single mode beam wind to vortex-induced vibration generalized coordinates equation is:

$M\&CenterDot;\left(\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&xi;}}+2{\mathrm{\&zeta;\&omega;}}_0\stackrel{\&CenterDot;}{\mathrm{\&xi;}}+{{\mathrm{\&omega;}}_0}^2\mathrm{\&xi;}\right)={\&Integral;}_{H_0}\frac{1}{2}{\mathrm{\&rho;U}}^2{{\mathrm{DC}}^{\&prime;}}_L\left(H\right)\left|\mathrm{\&phi;}\left(H\right)\right|\sin \left({\mathrm{\&omega;}}_{s}t+\mathrm{\&alpha;}\right)\&CenterDot;dH---\left(4\right)$

In formula, ζ is vibrational structure damping ratio; ω ₀for structural natural frequencies; H ₀for height of column; M is generalized mass:

$M={\&Integral;}_{H_0}{\mathrm{m\&phi;}}^2\&CenterDot;dH---\left(5\right)$

Wherein m is cylinder linear mass.

It should be noted that, when there is vortex-induced vibration, fluctuating lift coefficient C' _l(H) symbol can change along with mode factor φ (H) sign modification, therefore, mode factor must be added absolute value when doing integration, to ensure that fluctuating lift coefficient and mode factor direction are consistent.

Definition equivalent mass m _eqfor:

$m_{eq}=\frac{M}{{\&Integral;}_{H_0}{\mathrm{\&phi;}}^2\left(H\right)dH}---\left(6\right)$

And:

$\mathrm{\&psi;}=\frac{1}{H_0}{\&Integral;}_{H_0}{\mathrm{\&phi;}}^2\left(H\right)dH---\left(7\right)$

Parameter C' _lchange with changes of section.Definable cross section is with reference to cross section, and the changes in aerodynamic forces coefficient μ (H) that definition is caused by changes of section is all the other cross sections C' _l(H) with reference cross section C' _l(H _r) ratio, that is:

$\mathrm{\&mu;}\left(H\right)=\frac{C_L^{\&prime;}\left(H\right)}{C_L^{\&prime;}\left(H_R\right)}---\left(8\right)$

Formula (4) can be rewritten as:

$\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&xi;}}+2{\mathrm{\&zeta;\&omega;}}_0\stackrel{\&CenterDot;}{\mathrm{\&xi;}}+{{\mathrm{\&omega;}}_0}^2\mathrm{\&xi;}=\frac{F_R}{m_{eq}\mathrm{\&psi;}}\&CenterDot;F_t---\left(9\right)$

In formula $F_R=\frac{1}{2}{\mathrm{\&rho;U}}^2{D}_R{\mathrm{HC}}_L^{\&prime;}\left(H_R\right),$ And

$F_t=\frac{1}{H_0}{\&Integral;}_{H_0}\mathrm{\&mu;}\left(H\right)\left|\mathrm{\&phi;}\left(H\right)\right|sin({\mathrm{\&omega;}}_{s}t+\mathrm{\&alpha;})\&CenterDot;dH---\left(10\right)$

In order to calculate vortex-induced vibration result, research vortex-induced vibration amplitude, introduces the concept discussion F that power relevance function is swashed in whirlpool further _t, its correlation function

$R_{F\left(\mathrm{\&tau;}\right)}=\frac{1}{{H_0}^2}{\&Integral;}_{H_0}{\&Integral;}_{H_0}\mathrm{\&mu;}\left(H_1\right)\left|\mathrm{\&phi;}\left(H_1\right)\right|\&CenterDot;\mathrm{\&mu;}\left(H_2\right)\left|\mathrm{\&phi;}\left(H_2\right)\right|\&CenterDot;R_{f\left(\mathrm{\&tau;}\right)}\&CenterDot;{\mathrm{dH}}_1{\mathrm{dH}}_2---\left(11\right)$

Function R in formula _{f (τ)}represent f _s(t, H)=sin (ω _st+ α) corresponding to correlation function.

According to Fourier conversion, corresponding spectrum density is

$S_F\left(\mathrm{\&omega;}\right)=\frac{1}{{H_0}^2}{\&Integral;}_{H_0}{\&Integral;}_{H_0}\mathrm{\&mu;}\left(H_1\right)\left|\mathrm{\&phi;}\left(H_1\right)\right|\&CenterDot;\mathrm{\&mu;}\left(H_2\right)\left|\mathrm{\&phi;}\left(H_2\right)\right|\&CenterDot;S_f(\mathrm{\&omega;},|H_2-H_1\left|\right)\&CenterDot;{\mathrm{dH}}_1{\mathrm{dH}}_2---\left(12\right)$

Relation between recycling spatial spectrum correlation function can obtain:

$R(H_1,H_2,\mathrm{\&omega;})=\frac{S_F(H_1,H_2,\mathrm{\&omega;})}{S\left(\mathrm{\&omega;}\right)}---\left(13\right)$

Equation (12) arranges

$S_F\left(\mathrm{\&omega;}\right)=\frac{1}{{H_0}^2}{\&Integral;}_{H_0}{\&Integral;}_{H_0}\mathrm{\&mu;}\left(H_1\right)\left|\mathrm{\&phi;}\left(H_1\right)\right|\&CenterDot;\mathrm{\&mu;}\left(H_2\right)\left|\mathrm{\&phi;}\left(H_2\right)\right|\&CenterDot;R(\mathrm{\&omega;},|H_2-H_1\left|\right)S\left(\mathrm{\&omega;}\right)\&CenterDot;{\mathrm{dH}}_1{\mathrm{dH}}_2---\left(14\right)$

At the vortex-induced vibration of lock room, vortex acting frequency is consistent with structural vibration frequency, is generally single-frequency, and power spectrum is swashed in the whirlpool that S (ω) can regard pure two dimension as, and thinks that R and frequencies omega have nothing to do, and above formula can change into further:

S _F(ω)＝R _FS(ω)(15)

In formula $R_{F\left(\mathrm{\&tau;}\right)}=\frac{1}{{H_0}^2}{\&Integral;}_{H_0}{\&Integral;}_{H_0}\mathrm{\&mu;}\left(H_1\right)\left|\right|\mathrm{\&phi;}\left(H_1\right)|\&CenterDot;\mathrm{\&mu;}\left(H_2\right)|\mathrm{\&phi;}\left(H_2\right)|R\left(\right|H_2-H_1\left|\right){\mathrm{dH}}_1{\mathrm{dH}}_2$

And definition volume integral formula is

$Con\left(\mathrm{\&Delta;}H\right)=2{\&Integral;}_0^{H_0-\mathrm{\&Delta;}H}\mathrm{\&mu;}\left(H\right)\left|\mathrm{\&phi;}\left(H\right)\right|\&CenterDot;\mathrm{\&mu;}\left(H+\mathrm{\&Delta;}H\right)\left|\mathrm{\&phi;}\left(H+\mathrm{\&Delta;}H\right)\right|)dH---\left(16\right)$

Can be in the hope of conversion factor expression formula:

$\mathrm{\&Phi;}=\sqrt{R_F}=\frac{1}{H_0}\sqrt{{\&Integral;}_0^{H_0}Con\left(\mathrm{\&Delta;}H\right)R\left(\mathrm{\&Delta;}H\right)d\mathrm{\&Delta;}H}---\left(17\right)$

In formula, R (Δ H) is for swashing power along across to correlation function in whirlpool, and accurate correlation function R (Δ H) obtains by test.The approximate formula that power index of correlation is swashed in the whirlpool obtained for uniform beam matching is

$R\left(\mathrm{\&Delta;}H\right)=\exp \&lsqb;-f_1\left(\mathrm{\&eta;}\right){\left(\frac{\mathrm{\&Delta;}H}{D_R}\right)}^{f_2\left(\mathrm{\&eta;}\right)}\&rsqb;---\left(18\right)$

Wherein η is that amplitude and beam wind are to dimension D _rratio;

Under generalized coordinates, vortex-induced vibration equation (9) can be rewritten as:

$\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&xi;}}+2{\mathrm{\&zeta;\&omega;}}_0\stackrel{\&CenterDot;}{\mathrm{\&xi;}}+{{\mathrm{\&omega;}}_0}^2\mathrm{\&xi;}=\frac{F_R}{m_{eq}\mathrm{\&psi;}}\&CenterDot;\mathrm{\&Phi;}sin({\mathrm{\&omega;}}_{s}t+{\mathrm{\&alpha;}}_0)---\left(19\right)$

For stable vortex-induced vibration, its expression formula just should be (remaining) string form, and vortex-induced vibration motion steady state solution is:

$\mathrm{\&xi;}\left(t\right)=\frac{W_0}{m_{eq}\mathrm{\&psi;}}\&CenterDot;\mathrm{\&Phi;}sin({\mathrm{\&omega;}}_{s}t-{\mathrm{\&theta;}}_0)---\left(20\right)$

Wherein θ ₀determined by initial position, and

$W_0=\frac{F_R}{{\mathrm{\&omega;}}_0^2\sqrt{{(1-{\mathrm{\&lambda;}}_0^2)}^2+{\left(2{\mathrm{\&zeta;\&lambda;}}_0\right)}^2}}$

In formula ${\mathrm{\&lambda;}}_0=\frac{{\mathrm{\&omega;}}_s}{{\mathrm{\&omega;}}_{ev}}$

According to Si Telaohaer relation, formula (1) is known:

The anti-vortex-induced vibration performance improving structure can, by the section form of change structure, allow cross section become more streamlined, and to reduce the numerical value of Si Telaohaer, that can improve structure vortex-induced vibration like this sends out the wind speed that shakes, and avoids structure generation vortex-induced vibration.But this mode can only ensure the anti-vortex-induced vibration better performances of single wind direction, the anti-vortex-induced vibration performance of all the other wind directions will be deteriorated.

Secondly the anti-vortex-induced vibration performance of structure is improved by structural measure, mainly by improving the rigidity of structure to improve the eigentone of structure.When section form one timing of structure, structural natural frequencies improves, and vortex-induced vibration sends out wind speed also proportional raising of shaking.When send out shake the basic wind speed of wind speed higher than residing environment time, can think that structure vortex-induced vibration can not occur.But, for practical structures, adopt the rigidity of structural measure raising structure very difficult, improve its eigentone very limited.

The third amplitude mode reducing vortex-induced vibration is can by the mode of plus structural damping, and according to formula (20) result of deriving, if structural damping is larger, its vortex-induced vibration amplitude will be less.But although the mode of plus structural damping can effectively reduce the vortex-induced vibration amplitude of structure, adopt which to suppress amplitude will additionally need to install damping system, cost is higher, the later stage also needs to inject capital in addition maintenance.

According to formula (20) derivation result, namely vortex-induced vibration amplitude is directly proportional to vortex-induced vibration amplitude conversion factor, and according to vortex-induced vibration amplitude conversion factor definition (17), it is relevant that power correlation is swashed in vortex-induced vibration amplitude conversion factor and whirlpool.The utility model is fully recognized that whirlpool, cross section is swashed power related fall and is conducive to suppressing vortex-induced vibration amplitude, and Cross section Design is become HELICAL ROTATING structure, object allows the whirlpool of structure swash power correlation decay as early as possible.Meanwhile, this form of structure avoids and adopts streamlined structure only in the anti-vortex-induced vibration of single direction drawback of good performance, and later stage Maintenance free substantially, reduce cost.

Accompanying drawing explanation

Fig. 1 is that peripheral flow analyzes schematic diagram;

Fig. 2 is each parameter schematic diagram for regular hexagon cylinder;

Fig. 3 is damaged surface gradient parameter schematic diagram;

Fig. 4 is cross section is regular hexagon column structure schematic diagram;

Fig. 5 is cross section is rectangular column structure schematic diagram;

Fig. 6 is regular hexagon cylinder sample calculation figure.

Detailed description of the invention

Below by embodiment, the utility model is specifically described; embodiment is only for being further detailed the utility model; can not be interpreted as the restriction to the utility model protection domain, some nonessential improvement that those skilled in the art makes according to content of the present utility model and adjustment also belong to the scope of the utility model protection.

Composition graphs 2 and Fig. 3, Fig. 2 are the schematic diagrames indicating each parameter for regular hexagon cylinder; Fig. 3 is damaged surface gradient parameter schematic diagram; Fig. 2 and Fig. 3 is only used to indicate each parameter and defines the schematic diagram provided, and does not represent the concrete structure of the utility model resist fluids vortex-induced vibration cylinder.

The column structure of resist fluids vortex-induced vibration, described cylinder bottom is fixed on pedestal, and cylinder is the polygon that shape of cross section is identical, and cylinder has arbitrary cross section upwards to form helical structure to top by polygon rotation; Cylinder upwards can be adopted the form of structure of progressive reduction to top cross sectional area by bottom.

Helical structure length is not less than 1/4th of cylinder length.Under normal circumstances, cylinder is base foundation consolidation, top free state, and the consideration in order to cost also only can be not less than 1/4th length on cylinder top and be arranged to helical structure, and other bottoms of cylinder adopt other form of structure that cost is lower.

The structure of cylinder can be represented by following calculating formula: in calculating formula, each parameter is shown in that Fig. 2 and Fig. 3 indicates.

Wherein ρ, θ, H are respectively pole axis, corner, high three physical quantitys of post below cylindrical coordinate, and corresponding unit is respectively m, radian, m; ρ ₀representing the maximum radius in cross section, is constant; H ₀for post is high; I is the gradient 0≤i<1 of the gabarit of cylinder, i=tan (α), describe cross-sectional shape change function under polar coordinate system, f (0)=1, but nonidentical in 1, be not namely circular cross-section; Namely with pole section maximum radius ρ ₀place sets up cylindrical coordinate, works as corner when being 0, pole section radius is maximum; As f (β again ₀)=1, the β that definition is corresponding ₀to attach most importance to complex phase parallactic angle, 0< β ₀≤ 2 π.

Composition graphs 6, Fig. 6 is regular hexagon cylinder sample calculation figure, for regular hexagon cylinder:

Hexagonal cross-section equation functions is:

The repetition phase angle of hexagonal cross-section is

θ is rotatable phase angle.β represents along unit post height rotation radian.

β is nonidentical in 0, and namely cross section rotates along post height.For the cylinder having corner angle, during fluid winding flow, whirlpool mid-career student is near cylinder corner angle, when pole section rotates along post height, whirlpool is de-will produce phase difference, analyze known according to the derivation of equation, because the relation of power phase difference is swashed in whirlpool, its correlation will decay rapidly, thus suppress the vortex-induced vibration amplitude of cylinder.Generally desirable 5 ~ 10 times of capital diameter 2 (1-iH ₀) ρ ₀post height rotate one repeat phase angle β ₀.Vortex-induced vibration inhibition can better, and amplitude suppressing can reach more than 50%.

Fig. 4 is cross section is orthohexagonal column structure schematic diagram, and in this example, post height 8m, bottom diameter 160mm, top end diameter 80mm, take bottom as benchmark, the top anglec of rotation is 600 degree.

Fig. 5 is cross section is rectangular column structure schematic diagram, and in this example, long limit, cross section and minor face are than being 5:3, and long limit, bottom is 200mm, and long limit, top is 100mm, post height 10m, take bottom as benchmark, and the top anglec of rotation is 900 degree.

Claims (5)

1. a column structure for resist fluids vortex-induced vibration, described cylinder bottom is fixed on pedestal, it is characterized in that: described cylinder is the polygon that shape of cross section is identical, and cylinder has arbitrary cross section upwards to form helical structure to top by polygon rotation.

2. the column structure of resist fluids vortex-induced vibration according to claim 1, is characterized in that: the cross section of described cylinder is regular polygon.

3. the column structure of resist fluids vortex-induced vibration according to claim 1, is characterized in that: described cylinder is by bottom upwards or progressive reduction identical to top cross sectional area.

4. the column structure of resist fluids vortex-induced vibration according to claim 1, is characterized in that: described helical structure length is not less than 1/4th of cylinder length.

5. the column structure of the resist fluids vortex-induced vibration according to any one of Claims 1-4, is characterized in that, the structure of described cylinder is represented by following calculating formula:

Wherein ρ, θ, H are respectively pole axis, corner, high three physical quantitys of post below cylindrical coordinate, and corresponding unit is respectively m, radian, m; ρ ₀representing the maximum radius in cross section, is constant; H ₀for post is high; I is the gradient 0≤i<1 of the gabarit of cylinder, i=tan (α), describe cross-sectional shape change function under polar coordinate system, f (0)=1, but nonidentical in 1, be not namely circular cross-section; Namely with pole section maximum radius ρ ₀place sets up cylindrical coordinate, works as corner when being 0, pole section radius is maximum; As f (β again ₀)=1, the β that definition is corresponding ₀to attach most importance to complex phase parallactic angle, 0< β ₀≤ 2 π.