T形截面振子的驰振特性试验研究
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摘要
T形振子的流致振动响应表现出了"非自限制"特性,随着流速的增大出现驰振现象,振动增强,有利于能量利用。但T形振子在复杂环境条件及自身截面变化条件下的研究尚未开展。基于此,进行了T形振子的试验研究,旨在探索其流致振动完整响应规律及在不同截面高宽比下的响应差异,具体结论如下:与三棱柱振子类似,T形振子也存在硬、软驰振现象,阻尼比较大时,出现硬驰振现象,而阻尼比较小时出现软驰振现象;软驰振响应中,振子的驰振具有自激发特性,由涡激振动激发而成;硬驰振响应中,振子需外力才可激发驰振;随着截面高宽比的增大,振动响应逐渐由硬驰振转化为软驰振,且驰振分支中振幅与频率均有所降低。
The T-section prism will present the trend of unlimited amplitude response,which,to be exact,will undergo the galloping vibration as the velocity increases.This characteristic will benefit the energy harvest from the flow-induced motion(FIM).Until now,few studies focused on the galloping characteristics of T-section prisms under complicated conditions and different cross section factors.To this end,a series of experiments are conducted to investigate the complete responses of the T-section prism and the influence of the cross section factor(height/width ratio).The main findings are listed as follows:two types of galloping,i.e.the soft galloping(SG)and hard galloping(HG),are found for the T-section prism.This feature has already been found in the triangular prism.When the damping is high,the prism presents the HG behavior,otherwise it presents the SG behavior.In the SG response,the galloping is self-excited by vortex induced vibration(VIV).In the HG response,the galloping must be excited by external forces.As the cross section factor increases,the oscillation is transformed from HG to SG,and the amplitudes and frequencies will both decrease.
The T-section prism will present the trend of unlimited amplitude response,which,to be exact,will undergo the galloping vibration as the velocity increases.This characteristic will benefit the energy harvest from the flow-induced motion(FIM).Until now,few studies focused on the galloping characteristics of T-section prisms under complicated conditions and different cross section factors.To this end,a series of experiments are conducted to investigate the complete responses of the T-section prism and the influence of the cross section factor(height/width ratio).The main findings are listed as follows:two types of galloping,i.e.the soft galloping(SG)and hard galloping(HG),are found for the T-section prism.This feature has already been found in the triangular prism.When the damping is high,the prism presents the HG behavior,otherwise it presents the SG behavior.In the SG response,the galloping is self-excited by vortex induced vibration(VIV).In the HG response,the galloping must be excited by external forces.As the cross section factor increases,the oscillation is transformed from HG to SG,and the amplitudes and frequencies will both decrease.
引文
[1]白莱文斯.流体诱发振动[M].吴恕三,译.北京:机械工业出版社,1981.Blenvins R D.Flow-Induced Vibration[M].Wu Shusan,Trans.Beijing:China Machine Press,1981.
[2]黄坤,冯奇.梁索耦合结构的风致涡激振动[J].振动工程学报,2011,24(2):139-145.Huang Kun,Feng Qi.The vortex-excited vibrations of coupled structure of cable-stayed beam[J].Journal of Vibration Engineering,2011,24(2):139-145.
[3]秦浩,廖海黎,李明水.大跨度变截面连续钢箱梁桥涡激振动线性分析法[J].振动工程学报,2015,28(6):966-971.Qin Hao,Liao Haili,Li Mingshui.A linear theory of vortex-induced vibration of long span continuous steel box girder bridge with variable cross-section[J].Journal of Vibration Engineering,2015,28(6):966-971.
[4] Bernitsas M M,Raghavan K,Ben-Simon Y,et al.VIVACE(Vortex Induced Vibration Aquatic Clean Energy):A new concept in generation of clean and renewable energy from fluid flow[J].Journal of Offshore Mechanics and Arctic Engineering,2008,130(4):041101.
[5] Lee J H,Bernitsas M M.High-damping,high-Reynolds VIV tests for energy harnessing using the VIVACE converter[J].Ocean Engineering,2011,38(16):1697-1712.
[6] Sun H,Kim E S,Bernitsas M P,et al.Virtual spring-damping system for flow-induced motion experiments[J].Journal of Offshore Mechanics and Arctic Engineering,2015,137(6):061801.
[7] Chang C C J,Kumar R A,Bernitsas M M.VIV and galloping of single circular cylinder with surface roughness at 3.0×104≤Re≤1.2×105[J].Ocean Engineering,2011,38(16):1713-1732.
[8] Bernitsas M M,Ben-Simon Y,Raghavan K,et al.The VIVACE converter:Model tests at high damping and Reynolds number around 105[J].Journal of Offshore Mechanics and Arctic Engineering,2009,131(1):011102.
[9] Sun H,Kim E S,Nowakowski G,et al.Effect of mass-ratio,damping,and stiffness on optimal hydrokinetic energy conversion of a single,rough cylinder in flow induced motions[J].Renewable Energy,2016,99:936-959.
[10]Ma C,Sun H,Nowakowski G,et al.Nonlinear piecewise restoring force in hydrokinetic power conversion using flow induced motions of single cylinder[J].Ocean Engineering,2016,128:1-12.
[11]Park H,Kumar R A,Bernitsas M M.Enhancement of flow-induced motion of rigid circular cylinder on springs by localized surface roughness at 3.0×104≤Re≤1.2×105[J].Ocean Engineering,2013,72:403-415.
[12]Zhang J,Xu G,Liu F,et al.Experimental investigation on the flow induced vibration of an equilateral triangle prism in water[J].Applied Ocean Research,2016,61:92-100.
[13]Lian J,Yan X,Liu F,et al.Experimental investigation on soft galloping and hard galloping of triangular prisms[J].Applied Sciences,2017,7(2):198.
[14]练继建,任泉超,刘昉,等.T形截面振子的流致振动特性试验研究[J].实验力学,2017,32(2):216-222.Lian Jijian,Ren Quanchao,Liu Fang,et al.Experimental study of flow-induced vibration characteristics of T-shape cross-section oscillator[J].Journal of Experimental Mechanics,2017,32(2):216-222.
[15]Morse T L,Govardhan R N,Williamson C H K.The effect of end conditions on the vortex-induced vibration of cylinders[J].Journal of Fluids and Structures,2008,24(8):1227-1239.
[16]Shao N,Lian J,Xu G,et al,Experimental investigation of flow-induced motion and energy conversion of a T-Section prism[J].Energies,2018,11(8):2035.
[17]Lian J,Yan X,Liu F,et al.Analysis on flow induced motion of cylinders with different cross sections and the potential capacity of energy transference from the flow[J].Shock and Vibration,2017,2017:1-19.
[2]黄坤,冯奇.梁索耦合结构的风致涡激振动[J].振动工程学报,2011,24(2):139-145.Huang Kun,Feng Qi.The vortex-excited vibrations of coupled structure of cable-stayed beam[J].Journal of Vibration Engineering,2011,24(2):139-145.
[3]秦浩,廖海黎,李明水.大跨度变截面连续钢箱梁桥涡激振动线性分析法[J].振动工程学报,2015,28(6):966-971.Qin Hao,Liao Haili,Li Mingshui.A linear theory of vortex-induced vibration of long span continuous steel box girder bridge with variable cross-section[J].Journal of Vibration Engineering,2015,28(6):966-971.
[4] Bernitsas M M,Raghavan K,Ben-Simon Y,et al.VIVACE(Vortex Induced Vibration Aquatic Clean Energy):A new concept in generation of clean and renewable energy from fluid flow[J].Journal of Offshore Mechanics and Arctic Engineering,2008,130(4):041101.
[5] Lee J H,Bernitsas M M.High-damping,high-Reynolds VIV tests for energy harnessing using the VIVACE converter[J].Ocean Engineering,2011,38(16):1697-1712.
[6] Sun H,Kim E S,Bernitsas M P,et al.Virtual spring-damping system for flow-induced motion experiments[J].Journal of Offshore Mechanics and Arctic Engineering,2015,137(6):061801.
[7] Chang C C J,Kumar R A,Bernitsas M M.VIV and galloping of single circular cylinder with surface roughness at 3.0×104≤Re≤1.2×105[J].Ocean Engineering,2011,38(16):1713-1732.
[8] Bernitsas M M,Ben-Simon Y,Raghavan K,et al.The VIVACE converter:Model tests at high damping and Reynolds number around 105[J].Journal of Offshore Mechanics and Arctic Engineering,2009,131(1):011102.
[9] Sun H,Kim E S,Nowakowski G,et al.Effect of mass-ratio,damping,and stiffness on optimal hydrokinetic energy conversion of a single,rough cylinder in flow induced motions[J].Renewable Energy,2016,99:936-959.
[10]Ma C,Sun H,Nowakowski G,et al.Nonlinear piecewise restoring force in hydrokinetic power conversion using flow induced motions of single cylinder[J].Ocean Engineering,2016,128:1-12.
[11]Park H,Kumar R A,Bernitsas M M.Enhancement of flow-induced motion of rigid circular cylinder on springs by localized surface roughness at 3.0×104≤Re≤1.2×105[J].Ocean Engineering,2013,72:403-415.
[12]Zhang J,Xu G,Liu F,et al.Experimental investigation on the flow induced vibration of an equilateral triangle prism in water[J].Applied Ocean Research,2016,61:92-100.
[13]Lian J,Yan X,Liu F,et al.Experimental investigation on soft galloping and hard galloping of triangular prisms[J].Applied Sciences,2017,7(2):198.
[14]练继建,任泉超,刘昉,等.T形截面振子的流致振动特性试验研究[J].实验力学,2017,32(2):216-222.Lian Jijian,Ren Quanchao,Liu Fang,et al.Experimental study of flow-induced vibration characteristics of T-shape cross-section oscillator[J].Journal of Experimental Mechanics,2017,32(2):216-222.
[15]Morse T L,Govardhan R N,Williamson C H K.The effect of end conditions on the vortex-induced vibration of cylinders[J].Journal of Fluids and Structures,2008,24(8):1227-1239.
[16]Shao N,Lian J,Xu G,et al,Experimental investigation of flow-induced motion and energy conversion of a T-Section prism[J].Energies,2018,11(8):2035.
[17]Lian J,Yan X,Liu F,et al.Analysis on flow induced motion of cylinders with different cross sections and the potential capacity of energy transference from the flow[J].Shock and Vibration,2017,2017:1-19.