With the development of the offshore deep water oil industry many researchers are focusing on the vortex-induced vibrations （VIV） of deep risers. In the present work, Reynolds-averaged Navier-Stokes （RANS） equatio...With the development of the offshore deep water oil industry many researchers are focusing on the vortex-induced vibrations （VIV） of deep risers. In the present work, Reynolds-averaged Navier-Stokes （RANS） equations were combined with the SST κ-ω turbulent model to simulate the stream-wise and transverse motion of an elastically mounted cylinder with a low mass-ratio, a natural frequency ratio of fx/fy = 1 and an Re number between 5 300 and 32 000, The four-order Runge-Kutta method was applied to solve the oscillating equation of the cylinder. The relationship between reduced velocity and parameters of the cylinder, including the lift coefficient, the drag coefficient, displacement and the vortex structure were then compared with recent experimental results and discussed in detail. The present numerical simulation reproduced effects have been observed in experiments, such as the lock-in phenomenon, the hysteretic phenomenon and beating behavior.展开更多
G861.4我国优秀激流回旋运动员运动素质训练监测指标的研究=A study on the top Chinese slalom kayakingpaddlers’physiccal fitness training and moni-toring indexes[刊,中,A]／余帆(天津商学院)∥武汉体育学院学报.-2004,38(1).-6...G861.4我国优秀激流回旋运动员运动素质训练监测指标的研究=A study on the top Chinese slalom kayakingpaddlers’physiccal fitness training and moni-toring indexes[刊,中,A]／余帆(天津商学院)∥武汉体育学院学报.-2004,38(1).-69-72表3参4(SJ)展开更多
A reduced three-degree-of-freedom model simulating the fluid-structure interactions （FSI） of the turbine blades and the on- coming air flows is proposed. The equations of motions consist of the coupling of bending a...A reduced three-degree-of-freedom model simulating the fluid-structure interactions （FSI） of the turbine blades and the on- coming air flows is proposed. The equations of motions consist of the coupling of bending and torsion of a blade as well as a van der Pol oscillation which represents the time-varying of the fluid. The 1：1 internal resonance of the system is analyzed with the multiple scale method, and the modulation equations are derived. The two-parameter bifurcation diagrams are computed. The effects of the system parameters, including the detuning parameter and the reduced frequency, on responses of the struc- ture and fluid are investigated. Bifurcation curves are computed and the stability is determined by examining the eigenvalues of the Jacobian matrix. The results indicate that rich dynamic phenomena of the steady-state solutions including the sad- dle-node and Hopf bifurcations can occur under certain parameter conditions. The parameter region where the unstable solu- tions occur should be avoided to keep the safe operation of the blades. The analytical solutions are verified by the direct nu- merical simulations.展开更多
文摘With the development of the offshore deep water oil industry many researchers are focusing on the vortex-induced vibrations （VIV） of deep risers. In the present work, Reynolds-averaged Navier-Stokes （RANS） equations were combined with the SST κ-ω turbulent model to simulate the stream-wise and transverse motion of an elastically mounted cylinder with a low mass-ratio, a natural frequency ratio of fx/fy = 1 and an Re number between 5 300 and 32 000, The four-order Runge-Kutta method was applied to solve the oscillating equation of the cylinder. The relationship between reduced velocity and parameters of the cylinder, including the lift coefficient, the drag coefficient, displacement and the vortex structure were then compared with recent experimental results and discussed in detail. The present numerical simulation reproduced effects have been observed in experiments, such as the lock-in phenomenon, the hysteretic phenomenon and beating behavior.
文摘G861.4我国优秀激流回旋运动员运动素质训练监测指标的研究=A study on the top Chinese slalom kayakingpaddlers’physiccal fitness training and moni-toring indexes[刊,中,A]／余帆(天津商学院)∥武汉体育学院学报.-2004,38(1).-69-72表3参4(SJ)
基金supported by the National Basic Research Program of China(“973” Project)(Grant No.2015CB057405)the National Natural Science Foundation of China(Grant No.11372082)the State Scholarship Fund of CSC
文摘A reduced three-degree-of-freedom model simulating the fluid-structure interactions （FSI） of the turbine blades and the on- coming air flows is proposed. The equations of motions consist of the coupling of bending and torsion of a blade as well as a van der Pol oscillation which represents the time-varying of the fluid. The 1：1 internal resonance of the system is analyzed with the multiple scale method, and the modulation equations are derived. The two-parameter bifurcation diagrams are computed. The effects of the system parameters, including the detuning parameter and the reduced frequency, on responses of the struc- ture and fluid are investigated. Bifurcation curves are computed and the stability is determined by examining the eigenvalues of the Jacobian matrix. The results indicate that rich dynamic phenomena of the steady-state solutions including the sad- dle-node and Hopf bifurcations can occur under certain parameter conditions. The parameter region where the unstable solu- tions occur should be avoided to keep the safe operation of the blades. The analytical solutions are verified by the direct nu- merical simulations.
