节段模型气动导纳的数值模拟与试验
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摘要
为了对桥梁风工程中广泛使用的气动导纳进行精细化研究,针对桥梁风工程中由于沿用了经典的薄机翼气动力理论,认为气动导纳仅是量纲一折算频率的函数而与风场特性无关这个问题,首先简要回顾了二维薄机翼非定常气动力理论的基本假定,指出对于钝体桥梁断面,这些基本前提条件不再成立,因此也不存在独立于风场特性的气动导纳函数。在这一理论观点的指导下,利用节段模型风洞测压试验,在3种非均匀布置的格栅湍流场中测量了平板断面和高宽比为1∶4矩形断面的脉动升力,并识别出各自的气动导纳函数。通过比较不同风场下识别的气动导纳函数,研究了不同形式断面与风场的依赖性。然后利用CFD数值模拟,通过改变入口边界条件,在3类湍流场中对结果进行了进一步的验证。试验及数值结果表明:平板断面的气动导纳在3类风场中基本一致,表现出了流线型断面对来流特性的不敏感性,可以认为是量纲一折算频率的单一函数;相比之下,具有钝体特性的矩形断面在3类不同风场中识别的气动导纳区别十分显著,表明钝体断面的气动导纳并不能定性为断面的函数,而是由断面与来流风场特性共同确定。在桥梁风工程中,需谨慎应用源于机翼理论的气动导纳概念,试验识别气动导纳时宜考虑与实际情况相符的风场特性。
The authors reviewed some fundamental assumptions that lead to aerodynamic load theories of two-dimensional thin airfoils to further investigate the aerodynamic admittance of twodimensional thin airfoil theories used in bridge aerodynamics,which adopts the concept of aerodynamic admittances determined uniquely by the dimensionless frequency and independent of wind field properties.These basic conditions do not hold for bluff bridge deck sections,so that aerodynamic admittance functions that are independent of the wind field properties are not available.Based on this theoretical viewpoint,the fluctuating lift forces of a flat plate and a rectangular section with an aspect ratio of 4 were measured through wind tunnel pressure measurement tests in three types of nonuniform arrangement grid-turbulence wind fields,and the aerodynamic admittance functions were identified.By comparing the aerodynamic admittancefunctions identified in different wind fields,the dependence of the cross sections on wind fields was investigated.The results were further verified using CFD simulations in three types of turbulent wind fields by changing the inlet boundary conditions.The results indicate that for a thin plate,the identified aerodynamic admittance functions from three different wind fields cohere with each other,indicating insensitivity to the oncoming wind field.In contrast,for a bluff rectangular section,the aerodynamic admittance functions from the wind fields differ significantly.This indicates that the aerodynamic admittances of bluff sections are functions that are not uniquely determined by the sectional configuration,but rather jointly determined by the configuration and wind properties.The results presented in this paper show that caution should always be applied in the application of airfoil-originated concept of aerodynamic admittance to bridge aerodynamics,and the wind field used to identify the aerodynamic admittances should be in accordance with the actual wind field characteristics.
The authors reviewed some fundamental assumptions that lead to aerodynamic load theories of two-dimensional thin airfoils to further investigate the aerodynamic admittance of twodimensional thin airfoil theories used in bridge aerodynamics,which adopts the concept of aerodynamic admittances determined uniquely by the dimensionless frequency and independent of wind field properties.These basic conditions do not hold for bluff bridge deck sections,so that aerodynamic admittance functions that are independent of the wind field properties are not available.Based on this theoretical viewpoint,the fluctuating lift forces of a flat plate and a rectangular section with an aspect ratio of 4 were measured through wind tunnel pressure measurement tests in three types of nonuniform arrangement grid-turbulence wind fields,and the aerodynamic admittance functions were identified.By comparing the aerodynamic admittancefunctions identified in different wind fields,the dependence of the cross sections on wind fields was investigated.The results were further verified using CFD simulations in three types of turbulent wind fields by changing the inlet boundary conditions.The results indicate that for a thin plate,the identified aerodynamic admittance functions from three different wind fields cohere with each other,indicating insensitivity to the oncoming wind field.In contrast,for a bluff rectangular section,the aerodynamic admittance functions from the wind fields differ significantly.This indicates that the aerodynamic admittances of bluff sections are functions that are not uniquely determined by the sectional configuration,but rather jointly determined by the configuration and wind properties.The results presented in this paper show that caution should always be applied in the application of airfoil-originated concept of aerodynamic admittance to bridge aerodynamics,and the wind field used to identify the aerodynamic admittances should be in accordance with the actual wind field characteristics.
引文
[1]SEARS W R.Some Aspects of Non-stationary Airfoil Theory and Its Practical Application[J].Journal of the Aeronautical Sciences,1941,8(3):104-108.
[2]LIEPMANN H W.On the Application of Statistical Concepts to the Buffeting Problem[J].Journal of the Aeronautical Sciences,1952,19(12):793-800.
[3]DAVENPORT A G.Buffeting of a Suspension Bridge by Storm Winds[J].Journal of the Structural Division,1962,88(ST3):233-268.
[4]LAROSE G L.Gust Loading on Streamlined Bridge Decks[J].Journal of Fluids and Structures,1998,12(5):511-536.
[5]SANKARAN R,JANCAUSKAS E D.Direct Measurement of the Aerodynamic Admittance of Two-dimensional Rectangular Cylinders in Smooth and Turbulent Flows[J].Journal of Wind Engineering and Industrial Aerodynamics,1992,41(1/2/3):601-611.
[6]KAWATANI M,KIM H.Evaluation of Aerodynamic Admittance for Buffeting Analysis[J].Journal of Wind Engineering and Industrial Aerodynamics,1992,41(1/2/3):613-625.
[7]MIRANDA S D,PATRUNO L,RICCI M,et al.Numerical Study of a Twin Box Bridge Deck with Increasing Gap Ratio by Using RANS and LES Approaches[J].Engineering Structures,2015,99:546-558.
[8]ANINA S,RUDIGER H,STANKO B.Numerical Simulations and Experimental Validations of Force Coefficients and Flutter Derivatives of a Bridge Deck[J].Journal of Wind Engineering and Industrial Aerodynamics,2015,144:172-182.
[9]DANIELS S J,CASTRO I P,XIE Z T.Numerical Analysis of Freestream Turbulence Effects on the Vortex-induced Vibrations of a Rectangular Cylinder[J].Journal of Wind Engineering and Industrial Aerodynamics,2016,153:13-25.
[10]WU T,KAREEM A.An Overview of Vortex-induced Vibration(VIV)of Bridge Decks[J].Frontiers of Structural and Civil Engineering,2012,6(4):335-347.
[11]BRUSIANI F,MIRANDA S D,PATRUNO L,et al.On the Evaluation of Bridge Deck Flutter Derivatives Using RANS Turbulence Models[J].Journal of Wind Engineering and Industrial Aerodynamics,2013,119:39-47.
[12]RASMUSSEN J T,HEJLESEN M M,LARSEN A,et al.Discrete Vortex Method Simulations of the Aerodynamic Admittance in Bridge Aerodynamics[J].Journal of Wind Engineering and Industrial Aerodynamics,2010,98(12):7754-7766.
[13]HEJLESEN M M,RASMUSSEN J T,LARSEN A,et al.On Estimating the Aerodynamic Admittance of Bridge Sections by a Mesh-free Vortex Method[J].Journal of Wind Engineering and Industrial Aerodynamics,2015,146:117-127.
[14]唐煜,郑史雄,张龙奇,等.桥梁断面气动导纳的数值识别方法研究[J].空气动力学报,2015,33(5):706-713.TANG Yu,ZHENG Shi-xiong,ZHANG Long-qi,et al.Numerical Method for Identifying the Aerodynamic Admittance of Bridge Deck[J].Acta Aerodynamic Sinica,2015,33(5):706-713.
[15]ZHANG Z T,GE Y J,ZHANG W F.Superposability of Unsteady Aerodynamic Loads on Bridge Deck Sections[J].Journal of Central South University,2013,20(11):3202-3215.
[16]KARMAN T,SEARS W R.Airfoil Theory for NonUniform Motion[J].Journal of Aeronautical Sciences,1938,5(10):379-390.
[17]SCANLAN R H,JONES N P.Aeroelastic Analysis of Cable-stayed Bridges[J].Journal of Structural Engineering,1990,116:279-197.
[18]LAROSE G L.Experimental Determination of the Aerodynamic Admittance of a Bridge Deck Segment[J].Journal of Fluids and Structures,1999,13(7):1029-1040.
[19]徐自然,周奇,朱乐东.考虑模型抖振力跨向不完全相关性效应的气动导纳识别[J].实验流体力学,2014,28(5):39-46.XU Zi-ran,ZHOU Qi,ZHU Le-dong.Identification of Aerodynamic Admittances by Considering the Effect of Incomplete Span-wise Correlation of Buffeting Forces on Section Model[J].Journal of Experiments in Fluid Mechanics,2014,28(5):39-46.
[20]MENTER F R,KUNTZ M,LANGTRY R.Ten Years of Industrial Experience with the SST Turbulence Model[J].Turbulence,Heat and Mass Transfer,2003,4(1):625-632.
[21]DAVIDSON L,BILLSON M.Hybrid LES-RANS Using Synthesized Turbulent Fluctuations for Forcing in the Interface Region[J].International Journal of Heat and Fluid Flow,2006,27(6):1028-1042.
[2]LIEPMANN H W.On the Application of Statistical Concepts to the Buffeting Problem[J].Journal of the Aeronautical Sciences,1952,19(12):793-800.
[3]DAVENPORT A G.Buffeting of a Suspension Bridge by Storm Winds[J].Journal of the Structural Division,1962,88(ST3):233-268.
[4]LAROSE G L.Gust Loading on Streamlined Bridge Decks[J].Journal of Fluids and Structures,1998,12(5):511-536.
[5]SANKARAN R,JANCAUSKAS E D.Direct Measurement of the Aerodynamic Admittance of Two-dimensional Rectangular Cylinders in Smooth and Turbulent Flows[J].Journal of Wind Engineering and Industrial Aerodynamics,1992,41(1/2/3):601-611.
[6]KAWATANI M,KIM H.Evaluation of Aerodynamic Admittance for Buffeting Analysis[J].Journal of Wind Engineering and Industrial Aerodynamics,1992,41(1/2/3):613-625.
[7]MIRANDA S D,PATRUNO L,RICCI M,et al.Numerical Study of a Twin Box Bridge Deck with Increasing Gap Ratio by Using RANS and LES Approaches[J].Engineering Structures,2015,99:546-558.
[8]ANINA S,RUDIGER H,STANKO B.Numerical Simulations and Experimental Validations of Force Coefficients and Flutter Derivatives of a Bridge Deck[J].Journal of Wind Engineering and Industrial Aerodynamics,2015,144:172-182.
[9]DANIELS S J,CASTRO I P,XIE Z T.Numerical Analysis of Freestream Turbulence Effects on the Vortex-induced Vibrations of a Rectangular Cylinder[J].Journal of Wind Engineering and Industrial Aerodynamics,2016,153:13-25.
[10]WU T,KAREEM A.An Overview of Vortex-induced Vibration(VIV)of Bridge Decks[J].Frontiers of Structural and Civil Engineering,2012,6(4):335-347.
[11]BRUSIANI F,MIRANDA S D,PATRUNO L,et al.On the Evaluation of Bridge Deck Flutter Derivatives Using RANS Turbulence Models[J].Journal of Wind Engineering and Industrial Aerodynamics,2013,119:39-47.
[12]RASMUSSEN J T,HEJLESEN M M,LARSEN A,et al.Discrete Vortex Method Simulations of the Aerodynamic Admittance in Bridge Aerodynamics[J].Journal of Wind Engineering and Industrial Aerodynamics,2010,98(12):7754-7766.
[13]HEJLESEN M M,RASMUSSEN J T,LARSEN A,et al.On Estimating the Aerodynamic Admittance of Bridge Sections by a Mesh-free Vortex Method[J].Journal of Wind Engineering and Industrial Aerodynamics,2015,146:117-127.
[14]唐煜,郑史雄,张龙奇,等.桥梁断面气动导纳的数值识别方法研究[J].空气动力学报,2015,33(5):706-713.TANG Yu,ZHENG Shi-xiong,ZHANG Long-qi,et al.Numerical Method for Identifying the Aerodynamic Admittance of Bridge Deck[J].Acta Aerodynamic Sinica,2015,33(5):706-713.
[15]ZHANG Z T,GE Y J,ZHANG W F.Superposability of Unsteady Aerodynamic Loads on Bridge Deck Sections[J].Journal of Central South University,2013,20(11):3202-3215.
[16]KARMAN T,SEARS W R.Airfoil Theory for NonUniform Motion[J].Journal of Aeronautical Sciences,1938,5(10):379-390.
[17]SCANLAN R H,JONES N P.Aeroelastic Analysis of Cable-stayed Bridges[J].Journal of Structural Engineering,1990,116:279-197.
[18]LAROSE G L.Experimental Determination of the Aerodynamic Admittance of a Bridge Deck Segment[J].Journal of Fluids and Structures,1999,13(7):1029-1040.
[19]徐自然,周奇,朱乐东.考虑模型抖振力跨向不完全相关性效应的气动导纳识别[J].实验流体力学,2014,28(5):39-46.XU Zi-ran,ZHOU Qi,ZHU Le-dong.Identification of Aerodynamic Admittances by Considering the Effect of Incomplete Span-wise Correlation of Buffeting Forces on Section Model[J].Journal of Experiments in Fluid Mechanics,2014,28(5):39-46.
[20]MENTER F R,KUNTZ M,LANGTRY R.Ten Years of Industrial Experience with the SST Turbulence Model[J].Turbulence,Heat and Mass Transfer,2003,4(1):625-632.
[21]DAVIDSON L,BILLSON M.Hybrid LES-RANS Using Synthesized Turbulent Fluctuations for Forcing in the Interface Region[J].International Journal of Heat and Fluid Flow,2006,27(6):1028-1042.