基于边缘射流的起落架气动噪声控制研究

Landing Gear Aerodynamic Noise Suppression with Edge Jet

起落架噪声可以看成是一系列结构件单独引起的气体扰流噪声以及这些不同结构件相对位置引起的干扰噪声的耦合。为了降低起落架气动噪声,提出一种基于边缘射流的主动控制技术。以某型飞机前起落架为研究对象,在其扭力臂背风面施加射流,利用分离涡脱模拟方法对其支柱和扭力臂结构简化模型的周围流场进行非定常计算,获取声源分布,采用FW-H积分获得远场噪声特性。结果表明:边缘射流能够有效抑制干扰噪声和支柱噪声,起落架的中频噪声得到一定幅度的下降,宽频噪声强度也有所减弱;射流改变扭力臂尾涡的脱落状况,可以减轻甚至消除涡脱落对支柱的冲击,从而减弱了支柱表面由于撞击而产生的脉动压力,达到降低声源强度的目的。

Landing gear noise can be regarded as the coupling with air turbulence noise which caused by series of structures alone and interference noise caused by relative position of different structures.In order to reduce the landing gear aerodynamic noise,a new method based on edge jet is proposed.Taking a certain type of aircraft landing gear as the research object,applying edge jet to the lee side of landing gear’s torque link,the flow field around the structure of the model is calculated by using detached eddy simulation,and the sound source distribution is obtained.The far field noise characteristic is obtained by using Ffowcs Williams-Hawkings（FW-H）integral.The results show that the edge jet can effectively suppress the interference and pillar noise,and the middle band noise of the landing gear can be reduced,and the broadband noise intensity is weakened.The flow of the jet is changed to reduce or even eliminate the impact of vortex shedding on the pillars.Thus,the surface fluctuating pressure is weakened,further more source intensity is decreased.