横向振动圆柱体在流体中的动力学特性

根据文献报道的圆柱体在无限域流场中横向振动时受到的流体作用力解析表达式,通过归纳定义和无量纲化处理得到了代表圆柱体在流体中动力学特性的无量纲动力附加质量和无量纲动力附加阻尼表达式,又通过分析各种因素对动力附加质量和动力附加阻尼的影响,研究了圆柱体在无限域流场中横向振动时的动力学特性。研究发现,圆柱体在流体中的动力学特性主要表现为动力附加质量和动力附加阻尼,而没有动力附加刚度,动力附加质量和动力附加阻尼均由反映流体流动滞流特性的滞流项和反映流体流动湍流特性的湍流项两部分组成,在不同流动状态下二者在总和中所占的比例不同,滞流主导状态下滞流项占主导,湍流主导状态下湍流项占主导。进一步分析表明,流体密度、流体粘度、圆柱体半径及圆柱体振动频率均对圆柱体在流体中的动力学特性有重要影响。

DYNAMIC CHARACTERISTICS OF A LATERAL VIBRATING CYLINDER IMMERSED IN UNBOUNDED FLUIDS

Based on the theoretical formula of fluid force acting on a lateral vibrating cylinder immersed in unbounded fluids,expressions for dimensionless dynamically additive mass and damping are obtained by inductive definition and non-dimensionalization.The dynamic characteristics of a lateral vibrating cylinder in unbounded fluids are studied by analyzing the influences of several factors on the dynamically additive mass and damping.It is discovered that the dynamic characteristics of the cylinder are represented by the dynamically additive mass and damping,but not the dynamically additive stiffness.The dynamically additive mass and damping both consist of two portions,namely stagnation,which represents the nature of laminar flow,and turbulence,which represents the nature of turbulent flow.Their contributions depend on the flow state.The stagnation portion dominates in stagnate flow,and the turbulence portion dominates in turbulent flow.Further,the dynamic characteristics of the cylinder are significantly influenced by fluid density and viscosity,cylinder radius,and the cylinder's vibrating frequency.