斜腹板傾角對(duì)橋梁氣動(dòng)穩(wěn)定性影響的數(shù)值模擬研究
發(fā)布時(shí)間：2018-09-08 10:10
【摘要】：自從1966年流線型箱梁被應(yīng)用于英國(guó)的賽文橋以來(lái),它就以較高的扭轉(zhuǎn)剛度、優(yōu)越的氣動(dòng)力特性和經(jīng)濟(jì)性而被橋梁設(shè)計(jì)者們廣泛采用。我國(guó)近幾十年來(lái)建造的大部分大跨度橋梁主梁都采用了流線型箱梁的形式。與傳統(tǒng)的大跨度桁架橋梁類似,顫振穩(wěn)定性仍是設(shè)計(jì)中要考慮的重要問(wèn)題,而另一個(gè)挑戰(zhàn)就是渦激振動(dòng),這也是箱梁斷面的固有特性之一。從空氣動(dòng)力學(xué)的角度看,流線型箱梁截面仍屬于鈍體,會(huì)導(dǎo)致氣流分離。箱梁的斜腹板的傾角越小,越趨近于平板,氣動(dòng)力特性就越好。然而過(guò)小的傾角會(huì)導(dǎo)致其他的問(wèn)題,如一些附屬構(gòu)件和設(shè)備的安裝。對(duì)南京四橋和其他一些大跨度流線型箱梁橋的風(fēng)洞試驗(yàn)表明,顫振臨界風(fēng)速會(huì)在斜腹板傾角小于16。時(shí)明顯提高。本文以南京四橋?yàn)楣こ瘫尘?以1：20的幾何縮尺比構(gòu)建計(jì)算模型。用數(shù)值模擬的方法研究了橋梁截面斜腹板傾角對(duì)氣動(dòng)穩(wěn)定性的影響及其抑制渦激振動(dòng)的機(jī)理。共研究了16種不同的傾角,分別為：12。-21。、23。、25。、35。、45。、75。和90。。本文研究的主要內(nèi)容有：(1)用二維N-S方程和SST k-ω湍流模型,采用定常算法進(jìn)行三分力計(jì)算,研究不同傾角對(duì)三分力的影響。研究結(jié)果表明,傾角的改變對(duì)阻力和升力系數(shù)影響較大,而對(duì)扭矩系數(shù)影響不明顯。且傾角越小,氣動(dòng)力特性越好。(2)用強(qiáng)迫振動(dòng)法對(duì)顫振性能進(jìn)行模擬計(jì)算,假設(shè)結(jié)構(gòu)分別做純豎向和純扭轉(zhuǎn)振動(dòng)并記錄升力和扭矩時(shí)程曲線,然后用最小二乘法擬合得到8個(gè)顫振導(dǎo)數(shù)。結(jié)果顯示：當(dāng)斜腹板傾角為17。時(shí),顫振導(dǎo)數(shù)H1*和A2*出現(xiàn)最小值。顫振穩(wěn)定性在傾角為17。時(shí)會(huì)大大提高。(3)用二維大渦模擬的方法進(jìn)行渦激振動(dòng)的分析,通過(guò)UDF編程實(shí)現(xiàn)結(jié)構(gòu)與流體的耦合。結(jié)果表明：當(dāng)斜腹板傾角小于17。時(shí),會(huì)抑制斜腹板后方大尺度漩渦的產(chǎn)生,從而有效減小渦激共振的可能性。
[Abstract]:Since the streamline box girder was applied to the Severn Bridge in England in 1966, it has been widely used by bridge designers because of its high torsional stiffness, superior aerodynamic characteristics and economy. In recent decades, most of the long-span bridge main beams are streamlined box girder. Similar to the traditional long-span truss bridge, flutter stability is still an important issue to be considered in the design, and another challenge is vortex-induced vibration, which is also one of the inherent characteristics of box girder section. From the viewpoint of aerodynamics, the section of streamlined box girder is still a blunt body, which will lead to the separation of air flow. The smaller the inclined angle of the box girder, the closer to the flat plate, the better the aerodynamic characteristics. However, too small inclination can lead to other problems, such as the installation of accessories and equipment. Wind tunnel tests of Nanjing fourth Bridge and other large span streamlined box girder bridges show that the critical flutter velocity is less than 16. Time is obviously improved. In this paper, the fourth Nanjing Bridge is used as the engineering background, and the calculation model is constructed with the geometric scale ratio of 1:20. The effect of inclined angle on aerodynamic stability and the mechanism of suppressing vortex-induced vibration are studied by means of numerical simulation. A total of 16 different inclination angles were studied, which are respectively: 1. 12. -21. 1. 23. 25. 5. 5. 5. 75. And 90. The main contents of this paper are as follows: (1) by using two-dimensional N-S equation and SST k- 蠅 turbulence model, a steady algorithm is used to calculate the three-point force, and the influence of different inclination angles on the three-point force is studied. The results show that the change of inclination angle has great influence on resistance and lift coefficient, but not on torque coefficient. And the smaller the inclination angle, the better the aerodynamic characteristics. (2) the flutter performance is simulated by forced vibration method, assuming the pure vertical and torsional vibration of the structure are made and the lift and torque time history curves are recorded, respectively. Then eight flutter derivatives are obtained by least square fitting. The results showed that the inclination angle of the oblique web was 17.7%. The flutter derivatives H 1 * and A 2 * are minimized. The flutter stability is 17. (3) the method of two-dimensional large eddy simulation is used to analyze the vortex-induced vibration, and the coupling between structure and fluid is realized by UDF programming. The results show that when the inclined web inclination is less than 17. The large scale vortex behind the oblique web can be inhibited and the possibility of VSR can be effectively reduced.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U441.3
本文編號(hào)：2230211
[Abstract]:Since the streamline box girder was applied to the Severn Bridge in England in 1966, it has been widely used by bridge designers because of its high torsional stiffness, superior aerodynamic characteristics and economy. In recent decades, most of the long-span bridge main beams are streamlined box girder. Similar to the traditional long-span truss bridge, flutter stability is still an important issue to be considered in the design, and another challenge is vortex-induced vibration, which is also one of the inherent characteristics of box girder section. From the viewpoint of aerodynamics, the section of streamlined box girder is still a blunt body, which will lead to the separation of air flow. The smaller the inclined angle of the box girder, the closer to the flat plate, the better the aerodynamic characteristics. However, too small inclination can lead to other problems, such as the installation of accessories and equipment. Wind tunnel tests of Nanjing fourth Bridge and other large span streamlined box girder bridges show that the critical flutter velocity is less than 16. Time is obviously improved. In this paper, the fourth Nanjing Bridge is used as the engineering background, and the calculation model is constructed with the geometric scale ratio of 1:20. The effect of inclined angle on aerodynamic stability and the mechanism of suppressing vortex-induced vibration are studied by means of numerical simulation. A total of 16 different inclination angles were studied, which are respectively: 1. 12. -21. 1. 23. 25. 5. 5. 5. 75. And 90. The main contents of this paper are as follows: (1) by using two-dimensional N-S equation and SST k- 蠅 turbulence model, a steady algorithm is used to calculate the three-point force, and the influence of different inclination angles on the three-point force is studied. The results show that the change of inclination angle has great influence on resistance and lift coefficient, but not on torque coefficient. And the smaller the inclination angle, the better the aerodynamic characteristics. (2) the flutter performance is simulated by forced vibration method, assuming the pure vertical and torsional vibration of the structure are made and the lift and torque time history curves are recorded, respectively. Then eight flutter derivatives are obtained by least square fitting. The results showed that the inclination angle of the oblique web was 17.7%. The flutter derivatives H 1 * and A 2 * are minimized. The flutter stability is 17. (3) the method of two-dimensional large eddy simulation is used to analyze the vortex-induced vibration, and the coupling between structure and fluid is realized by UDF programming. The results show that when the inclined web inclination is less than 17. The large scale vortex behind the oblique web can be inhibited and the possibility of VSR can be effectively reduced.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U441.3
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 周志勇,陳艾榮,項(xiàng)海帆;渦方法分析并列圓柱的旋渦脫落現(xiàn)象[J];空氣動(dòng)力學(xué)學(xué)報(bào);2003年01期
，本文編號(hào)：2230211
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