|
|
|
| Vortex-induced vibration time domain responses of flexible risers under oscillatory flows |
| YUAN Yu-chao1,2， XUE Hong-xiang1,2， TANG Wen-yong1,2 |
1.State Key Lab of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2.Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai Jiao Tong University, Shanghai 200240, China |
|
|
|
|
Abstract Introducing the hydrodynamic force coefficient database obtained with forced vibration tests and adopting the full-new judgement for lock-in region and the lock-in criterion, aiming at vortex-induced vibration (VIV) problems of flexible risers under oscillatory flows, a set of time domain predicting numerical methods for users to choose was proposed. VIV hydrodynamic forces were depended on instantaneous incoming flow velocity and motion of riser’s cross-section. The corresponding hydrodynamic force coefficients were functions of non-dimensional amplitude and frequency. Based on the proposed methods, the dynamic response of a certain 4m high riser model under oscillatory flows with different KC numbers and maximum reduced velocities was calculated. The prediction results agreed well with those of tests. Amplitude modulation, hysteresis, frequency transition and higher frequency resonances, etc. phenomena were observed in the predicted results. These features of the dynamic response of the riser under combined oscillatory flow cases with different KC numbers and maximum reduced velocities were distinguished from those under steady flow cases. They were analyzed from the view point of VIV occurrence mechanism and explained reasonably. Finally, comparing VIV responses of the riser under oscillatory flows with those under uniform flows, it was shown that under the similar flow velocity, the RMS of riser’s VIV displacement under oscillatory flows is larger than that under uniform flows; under the same maximum reduced velocity, the smaller KC number corresponds to a larger RMS of riser’s VIV displacement.
|
|
Received: 23 February 2017
Published: 28 June 2018
|
|
|
|
[1] Vandiver J.K., Li L., SHEAR7 V4.4 Program Theoretical Manual [P], Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 2005.
[2] Larsen C.M., Lie H., Passano E., Yttervik R., Wu J., Baarholm G., VIVANA Theory Manual (Version3.7) [P], Norwegian Marine Technology Research Institute, Trondheim, Norway, 2009.
[3] Chang S.H., Isherwood M., Vortex-induced vibrations of steel catenary risers and steel offloading lines due to platform heave motions [C]. Proceedings of the Offshore Technology Conference. Houston, Texas, USA, 2003.
[4] Sidarta D.E., Finn L.D., Maher J., Time domain FEA for riser VIV analysis[C]. Proceedings of the ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. Shanghai, China, 2010, paper No.OMAE2010-20688.
[5] Ma P., Qiu W., Time-domain VIV prediction of marine risers [C]. Proceedings of the ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. Rio de Janeiro, Brazil, 2012, OMAE2012-84269.
[6] Xue H.X., Wang K.P., Tang W.Y., A practical approach to predicting cross-flow and in-line VIV response for deepwater risers[J]. Applied Ocean Research, 2015, 52: 92-101.
[7] Liao J.C., Vortex-induced vibration of slender structures in unsteady flow [D]. Doctoral thesis, Massachusetts Institute of Technology, 2001.
[8] Resvanis T.L., Vortex-induced vibration of flexible cylinders in time-varying flows [D]. Doctoral thesis, Massachusetts Institute of Technology., 2014.
[9] Thorsen M.J., Sævik S., Larsen C.M., Time domain simulation of vortex-induced vibrations in stationary and oscillating flows [J]. Journal of Fluids and Structures, 2016, 61:1-19.
[10] Gopalkrishnan R., Vortex induced forces on oscillating bluff cylinders [D]. Doctoral thesis, Massachusetts Institute of Technology, 1993.
[11] Fu S.X., Wang J.G., Baarholm R., Wu J., Larsen C.M., Features of vortex-induced vibration in oscillatory flow [J]. Journal of Offshore Mechanics and Arctic Engineering, 2014, 136(1): 011801.
[12] 王俊高, 付世晓, 许玉旺, 宋磊建. 振荡来流下柔性立管涡激振动“分时特性”试验研究[J]. 振动与冲击, 2014, 33(21):1-7.
Wang J.G., Fu S.X., Xu Y.W., Song L.J. Tests for “time sharing” of vortex-induced vibration of a flexible cylinder in oscillatory flow [J]. Journal of Vibration and Shock, 2014, 33(21):1-7.
[13] Venugopal M., Damping and response of a flexible cylinder in a current [D]. Doctoral thesis, Massachusetts Institute of Technology, 1996.
[14] Zheng H.N., The influence of high harmonic force on fatigue life and its prediction via coupled Inline-Crossflow VIV modeling [D]. Doctoral thesis, Massachusetts Institute of Technology, 2014.
[15] Blevins R.D., Coughran C.S., Experimental Investigation of Vortex-induced Vibration in One and Two Dimensions with Variables Mass, Damping and Reynolds Number [J]. Journal of Fluids Engineering, 2009, 131(10), paper No. 101202.
[16] 戚兴. 隔水管流固耦合涡激振动数值模拟研究[D]. 硕士论文, 西南石油大学, 成都, 2014.
Qi X. Numerical simulation of fluid-structure interaction of vortex-induced vibration for marine risers [D]. Master's thesis, Southwest Petroleum University, Chengdu, 2014.
[17] 董婧, 宗智, 李章锐, 孙雷, 陈伟. 两自由度运动圆柱绕流的离散涡方法模拟[J]. 船舶力学, 2012, 16(1):9-20.
Dong J., Zong Z., Li Z.R., Sun L., Chen W. Numerical simulation of flow around a cylinder of two degrees of freedom motion using the discrete vortex method [J]. Journal of Ship Mechanics, 2012, 16(1):9-20.
[18] 曹淑刚, 黄维平, 顾恩凯. 考虑流固耦合的弹性圆柱体涡激振动研究[J]. 振动与冲击, 2015, 34(1):58-62.
Cao S.G., Huang W.P., Gu E.K. Vortex-induced vibration of an elastic cylinder considering fluid-structure interaction [J]. Journal of Vibration and Shock, 2015, 34(1):58-62.
|
|
|
|
