【作者】 徐国庆；

【导师】 Alam Md.Mahbub；

【作者基本信息】 哈尔滨工业大学 ， 动力工程及工程热物理， 2016， 硕士

【摘要】 在针对钝体绕流的研究中,流体诱发振动现象吸引了越来越多的研究者对其进行探索。流体诱发振动在许多工程领域中都有很重要的研究价值,尤其在用来评估钝体结构的稳定性方面,如桥梁,近海平台及高层建筑群等等。目前已有大量文献讲述圆柱结构体绕流的探究,相比之下方柱绕流及其流体诱发振动的研究需要更多关注。本文主要探究在低雷诺数条件下,上游固定方柱对下游弹性固定方柱的影响效果。本文采用有限体积法,在雷诺数为100以及200的条件下,探索下游方柱的振动情况及产生机理。对比单根方柱的振动情况,总结上游方柱在不同间距下对下游振动方柱的影响效果。在固定雷诺数及间距比的情况下,通过改变振动方柱的固有频率fN来实现对不同无量纲速度Ur的研究。在每一组仿真研究中,我们讨论了下游方柱的振动幅度A、振动频率fv以及阻力平均值CD和升力脉动值CL’随无量纲速度的改变而产生的变化情况,并归纳出相关的转捩点。此外,通过对瞬时的涡量及压力云图的分析,揭示上游固定方柱的漩涡脱落对下游振动方柱的作用机理,从而解释振动变化的原因。更多还原

【Abstract】 Considering the study of flow around bluff bodies, flow induced vibration phenomenon has attracted more and more researchers to explore. Flow induced vibration has a very important research value in many engineering fields, especially in the use of assessing the stability of blunt body structures, such as bridges, offshore platforms, high-rise buildings and so on. There are a lot of literatures about study of flow around cylindrical structure, compared with square column flow around and flow induced vibration of research needs more attention. In this paper, we explore the effects of the upstream fixed square cylinder applied on downstream elastic square cylinder in the condition of low Reynolds number.In present work, we explore the mechanism and the vibration of the downstream square cylinder situation under the condition of Reynolds number being 100 and 200 with the finite volume method. Compared with single square cylinder vibration situation, we summarized the effects that upstream square cylinder applied on the downstream vibrating square cylinder under different spacing. In the case of certain Reynolds number and spacing ratio, we implemented the study of different dimensionless velocity Ur through changing the natural frequency of vibration square cylinder, fN. In each simulation study group, we discussed the changes in vibration amplitude, vibration frequency, the mean drag coefficient and lift fluctuations of the downstream square cylinder, along with the change of dimensionless velocity, and searched for the corresponding turning point. In addition, by analyzing the instantaneous vorticity and pressure contours, we revealed the mechanism that how the upstream vortex shedding influence the vibration of downstream cylinder, so as to explain how the amplitude change with Ur.更多还原