多因素影响下四立柱涡激运动特性研究

发布时间：2018-03-09 21:05

本文选题：四立柱　切入点：涡激运动　出处：《江苏科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：由于国际上海洋石油工业的不断发展，海洋平台立柱的涡激运动这一问题受到了人们的关注。本论文跟踪了国内外有关柱体涡激运动的最新研究方向，对本领域内的研究方法和进展进行了综述和分析。以海洋平台四立柱为研究对象，介绍了涡激运动的有关理论、数值模拟方法和实验方法，对均匀流中四立柱的涡激运动进行了数值模拟，探索了截面形式、来流方向和间距比对涡激运动的影响，分析了四立柱涡激运动的幅值响应、频谱特性、运动轨迹和涡脱模式。论文的具体工作和主要研究成果如下： 1.较为全面的回顾和分析了国内外研究柱体涡激运动问题的动态和进展，系统介绍了涡激运动问题研究过程中所涉及的流体相关参数、结构物相关参数和耦合运动的相关参数。 2.采用动网格技术实现柱体在流场中的运动，开发FLUENT软件与结构运动特性之间的接口程序，实现流体信息和结构信息实时传递，并通过单柱体涡激运动数值模拟对接口程序进行验证。 3.在不同的折合速度下，对方形四立柱和圆形四立柱涡激运动特性进行对比研究。圆形四立柱的流向最大位移比方形四立柱小，但是横向最大位移是方形四立柱的3倍多。圆形四立柱涡激运动出现了频率锁定现象，而方形四立柱则没有。方形四立柱尾涡脱落模式总体呈现出2P模式，圆形四立柱尾涡脱落在折合速度较低时呈现P+S模式，高折合速度下为2S模式。 4.建立不同来流方向下方形四立柱涡激运动的模型，模拟0度、15度、30度和45度来流下方形四立柱涡激运动。来流方向对涡激运动特性有着很大的影响，0度来流所对应的横向振幅和流向振幅都是最小的，流向幅值在来流方向15度下达到最大值1.60D，，横向幅值在来流方向30度下达到最大值1.22D。由于柱体之间的相互干扰作用，运动轨迹和尾涡脱落模式都比较凌乱。 5.建立不同间距比下方形四立柱涡激运动的模型，模拟间距比3.0、4.0和5.0工况下方形四立柱涡激运动。间距比3.0、4.0和5.0工况下，流向和横向振幅随折合速度的增大先增大到一定的数值，然后在其值左右振荡。流向幅值在间距比5.0工况下达到最大值0.39D，横向幅值在间距比3.0下达到最大值1.22D。流向平衡位置远离初始位置的距离和升力系数的主频率均随着折合速度的增大而增大。
[Abstract]:Due to the continuous development of offshore oil industry, people pay close attention to the vortex-induced motion of offshore platform columns. In this paper, the latest research directions of column vortex-induced motion at home and abroad are followed. The research methods and progress in this field are summarized and analyzed. Taking the four columns of offshore platform as the research object, the theory, numerical simulation and experimental methods of vortex-induced motion are introduced. The vortex-induced motion of four columns in a uniform flow is simulated numerically. The effects of cross-section, direction and distance ratio of incoming flow on the vortex-induced motion are explored. The amplitude response and spectral characteristics of the vortex-induced motion of four columns are analyzed. Motion trajectory and vortex detach model. The specific work and main results of this paper are as follows:. 1. The dynamics and progress of the research on vortex-induced motion of cylinders at home and abroad are reviewed and analyzed. The fluid related parameters, structural parameters and coupled motion parameters are systematically introduced. 2. The moving grid technology is used to realize the motion of the cylinder in the flow field, and the interface program between the FLUENT software and the structure motion characteristic is developed to realize the real-time transmission of the fluid information and the structure information. The interface program is verified by numerical simulation of vortex-induced motion of a single cylinder. 3. The vortex-induced motion characteristics of square four columns and circular four columns are compared at different folding speeds. The maximum displacement of circular four columns is smaller than that of square four columns. However, the maximum lateral displacement is more than three times that of the square four columns. The circular four columns exhibit frequency locking phenomenon, while the square four columns do not. The trailing vortex shedding mode of the square four columns generally shows a 2P mode. The wake shedding of circular four columns shows P S mode when the folding velocity is low, and 2S mode at high folding speed. 4. The vortex-induced motion model of four square columns in different directions is established. The vortex-induced motion of the square four columns is simulated at 0 ~ 15 degrees, 30 ~ 30 and 45 degrees. The direction of flow has a great influence on the characteristics of vortex-induced motion. The lateral amplitude and the flow direction amplitude of the zero degree flow are the smallest. The amplitude of flow direction reaches the maximum value of 1.60D at 15 degrees in the direction of incoming flow and the maximum value of 1.22D at 30 degrees in the direction of incoming flow. Due to the interaction between cylinders, the motion path and the pattern of wake vortex shedding are relatively messy. 5. The vortex-induced motion model of square four columns with different spacing ratios is established. The simulation results show that the vortex-induced motion of square four-column is simulated under the conditions of 3.0 ~ 4.0 and 5.0 respectively, and the distance ratio is 3.0 ~ 4.0 and 5.0, respectively. The flow direction and the transverse amplitude increase to a certain value with the increase of the folding velocity. The amplitude of flow direction reaches the maximum of 0.39D at the condition of spacing ratio 5.0, and the amplitude of transverse amplitude reaches the maximum value of 1.22D when the distance ratio is 3.0. The distance between the equilibrium position of the flow direction and the initial position and the main frequency of the lift coefficient are with each other. The speed of folding increases.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U661.1;U674.381

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