变截面三维机翼的气动性能及噪声研究

Research on aerodynamic performance and noise of variable-section three-dimensional airfoil

为了深入研究接近于真实翼型的变截面三维翼型的气动性能以及噪声表现,构建了一个基于NACA 0018的变截面三维机翼模型,使用ANSYS Fluent软件对该模型进行气动性能以及气动噪声的研究。数值仿真模拟采用大涡模拟(LES)方法,使用WALL亚格子模型,研究了该三维翼型在攻角为15°、来流速度为40 m/s情况下的绕流特性。使用基于Lighthill声学类比模型的FW-H方程进行气动噪声的计算。结果显示,在机翼上表面某点之后开始不断形成分离泡产生流动不稳定性,造成压力和速度波动并产生波动的气动噪声,气动噪声在前缘驻点位置以及后缘位置达到最大值。机翼上表面开始产生分离泡之后,流动出现了在翼型展向位置上的横跨流动,这将加剧流动的不稳定性。

In order to have a deeper understanding of the aerodynamic performance and noise performance of the variable-section 3D airfoil that was close to the real airfoil,a 3D wing model with variable section based on NACA 0018 was constructed,and ANSYS Fluent software was used to study the aerodynamic performance and aerodynamic noise of the model.The numerical simulation adopted the large eddy simulation(LES)method based on the WALL model to study the flow characteristics of the three-dimensional airfoil when the angle of attack was 15°and the inflow velocity was 40 m/s.Aerodynamic noise was calculated using the FW-H equation based on the Lighthill acoustic analogy model.The results showed that,after a certain point on the upper surface of the wing,the continuous formation of separation bubbles produced flow instability,which caused pressure and velocity fluctuations and generated fluctuating aerodynamic noise.The aerodynamic noise reached the maximum at the leading edge stagnation point and the trailing edge.After separation bubbles began to form on the upper surface of the airfoil,the flow appeared spanwise across the airfoil,which would exacerbate flow instability.