首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3篇
  免费   0篇
地球物理   1篇
海洋学   2篇
  2019年   1篇
  2018年   1篇
  2014年   1篇
排序方式: 共有3条查询结果,搜索用时 93 毫秒
1
1.
Xie  Wu-de  Xu  Wan-hai  Zhai  Li-bin  Gao  Xi-feng  Xu  Zeng-wei 《中国海洋工程》2019,33(6):704-712
The marine risers are often subjected to parametric excitations from the fluctuation top tension. The top tension on the riser may fluctuate with multiple frequencies caused by irregular waves. In this paper, the influence between different frequency components in the top tension on the riser system is theoretically simulated and analyzed. With the Euler-Bernoulli beam theory, a dynamic model for the vibrations of the riser is established. The top tension is set as fluctuating with time and it has two different frequencies. The influences from the fluctuation amplitudes, circular frequencies and phase angles of these frequency components on the riser system are analyzed in detail. When these two frequencies are fluctuating in the stable regions, the riser system may become unstable because ω_1+ω_2≈2Ωn. The fluctuation amplitudes of these frequencies have little effect on the components of the vibration frequencies of the riser. For different phase angles, the stability and dynamic behaviors of the riser would be different.  相似文献   
2.
It is well known that the Reynolds number has a significant effect on the vortex-induced vibrations (VIV) of cylinders. In this paper, a novel in-line (IL) and cross-flow (CF) coupling VIV prediction model for circular cylinders has been proposed, in which the influence of the Reynolds number was comprehensively considered. The Strouhal number linked with the vortex shedding frequency was calculated through a function of the Reynolds number. The coefficient of the mean drag force was fitted as a new piecewise function of the Reynolds number, and its amplification resulted from the CF VIV was also taken into account. The oscillating drag and lift forces were modelled with classical van der Pol wake oscillators and their empirical parameters were determined based on the lock-in boundaries and the peak-amplitude formulas. A new peak-amplitude formula for the IL VIV was developed under the resonance condition with respect to the mass-damping ratio and the Reynolds number. When compared with the results from the experiments and some other prediction models, the present model could give good estimations on the vibration amplitudes and frequencies of the VIV both for elastically-mounted rigid and long flexible cylinders. The present model considering the influence of the Reynolds number could generally provide better results than that neglecting the effect of the Reynolds number.  相似文献   
3.
海底悬跨管道涡激振动问题十分复杂,需考虑流 管-土多场耦合效应。本文将悬跨管线简化为Euler-Bernoulli梁,两端跨肩管-土作用与线弹性弹簧和扭转弹簧近似,采用Van der pol方程描述旋涡脱落的尾迹特性。利用模态正交性对流-耦合控制方程进行解耦,采用龙格-库塔法进行数值求解,重点分析非对称边界对海底管道涡激振动特性的影响。计算结果表明:非对称边界条件对最大响应幅值影响不大;约束条件越强烈,模态激发越难,响应频率越高。  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号