扰动风作用下微型旋翼流场的数值模拟及流动控制研究

对于处在低雷诺数下的微型旋翼,扰动风对其流场影响很大。本文基于动态嵌套网格技术的双时间法,采用网格速度法模拟扰动风,研究了不同频率和幅值的正弦式扰动风下三维微型旋翼上的拉力系数响应情况,并采用变形网格方法模拟了旋翼桨叶的周期性边距运动对扰动风的流动控制,为今后旋翼机的主动控制研究提供了线索。研究结果表明,低雷诺数下,旋翼在周期性扰动风作用下的拉力响应曲线拟合函数与扰动风函数形式相同,响应曲线函数同样具有周期性变化趋势,波动幅值与扰动风幅值成正比例关系;对不同飞行状态下的旋翼,采用周期等角变距方式,能够找到一个适合的控制参数使得旋翼在正弦式扰动风环境下旋翼的拉力波动在一定范围内得到有效抑制。

Numerical simulation under disturbance wind and its flow control of flow field of micro rotary-wings

The disturbant wind has much effect on the flow field of micro rotary-wings under the low Reynolds number condition.In this paper,using the numerical simulation method (the moving overlapped grid technology and dual-time stepping method) to study the aerodynamic performance of the dimensional airfoil under the disturbance wind environment,by taking the movement form of the rotor deformation to control and search the flow with the disturbant wind.The study showed that: (a) Under the periodic disturbant wind,the fitting curve of the rotor tension response curve and the disturbant wind function form have the same cyclical trend,the fluctuation amplitude and the perturbation wind amplitude is the proportional relationship.(b) To the rotor model in different flight condition,taking the movement form of the cycle equiangular pitch,there will be able to find a suitable control parameter,which makes the fluctuation of the rotor tension in the disturbant wind to be effectively suppressed within a certain range.