基于Overset网格的圆柱涡激振动特性研究

Research on cylindrical vortex induced vibration characteristics based on overset grid

涡激振动广泛存在于海洋工程中。柱体是典型的绕流钝体,柱体涡激振动的数值模拟关键在于网格的质量。结构化网格或非结构化网格在处理较大振幅时,往往由于网格畸变导致负网格的出现,从而影响模拟的准确性。本文基于Overset这一动网格技术,对二维弹性柱体的横向涡激振动特性进行研究。结果表明:阻尼比对响应振幅的影响具有趋势一致性,在较小的范围内增加或降低柱体的振幅水平;质量比对响应振幅的影响更大,质量比越高,其对应的振幅越低,并能显著减小锁振区间;不同质量比及约化速度下,柱体的升阻力系数变化较大,且能捕捉到典型的拍级相位差现象。

Vortex-induced vibration is widely used in ocean engineering. Cylinder is a typical blunt body, and the quality of the grid is the key to the numerical simulation of vortex induced vibration of cylinder. When structured or unstructured grids deal with large amplitudes, negative grids often appear due to grid distortion, which affects the accuracy of simulation.In this paper, the characteristics of the transverse vortex-induced vibration of a two-dimensional elastic cylinder are studied based on the Overset technique. The results show that the effect of damping ratio on the response amplitude has a trend consistency, which increases or decreases the amplitude level of the cylinder in a small range. The higher the mass ratio is, the lower the corresponding amplitude is, and the lock-in interval can be significantly reduced. Under different mass ratios and reduced velocities, the lift and drag coefficients of the cylinder vary greatly, and the typical beat and phase difference phenomena can be captured.