方形四立柱涡激运动及水动力性能分析

Research on the vortex induced motion and hydrodynamic performance analysis of four square columns

平台涡激运动是近年来海洋工程领域研究的热点和难点。本文将涡激运动系统简化为两自由度质量-弹簧-阻尼模型,引入雷诺平均应力模型求解N-S方程,将求解瞬态动力响应的四阶Runge-Kutta代码嵌入UDF程序中并采用动网格技术实现流场更新,对低质量比弹性支撑方形四立柱涡激运动进行数值研究。研究表明:涡激运动流向最大位移为0.31D,横向最大位移为0.61D;横向运动频率随折合速度的增加而增大,没有出现频率锁定现象;不同约化速度下运动轨迹图较为紊乱;尾涡模式总体呈现出2P模式。

Vortex-induced motion of platform has been a hotspot and difficulty in the research of ocean engineering recently. In this paper,vortex-induced motion is simplified into spring-mass-damping model. Reynolds averaged stress model is adopted to solve the N- S equation. Fourth order Runge- Kutta method which is used to solve the instantaneous dynamic response was manually written into the User Defined Functions（ UDF）,and then dynamic mesh technology was adopted to realize the update of flow field,and simulate the vortex induced motion of elastic support square columns at low mass ratio. The research shows that： the stream-wise maximum amplitude is 0. 31 D,and the transverse maximum amplitude is 0. 61 D. The transversal motion frequency increases with the increasing of reduced velocity. There is no frequency lock- in phenomenon; Motion trajectory of different reduced velocity is inordinate. Trailing vortex pattern shows 2P mode.