基于嵌套网格和计入尾迹影响的旋翼流场数值模拟

给出了三维Euler方程数值模拟悬停状态旋翼流场的方法和模型。为充分考虑旋翼尾迹对流场的影响,采用了由动量理论导出的远场边界条件和由尾迹诱导速度代入滑移条件而构造的新翼面边界条件。为减少尾迹数值耗散和便于添加上述边界条件,采用了嵌套网格方法。针对嵌套网格中关键的贡献单元搜寻问题,本文采用一种伪贡献单元搜寻法。应用上述方法进行了算例计算,给出了有无尾迹修正时的旋翼桨叶表面压力分布和沿展向升力分布的计算结果,并与可得到的实验数据进行了对比。此外,从计算的等涡量线图上分析了旋翼尾迹流场畸变的发展趋势,表明了Euler方程法在旋翼涡尾迹捕捉方面的能力。

Numerical Simulation of Rotor Flowfield Based on Embedded Grids and Incorporated Wake Effects

A numerical method based on solutions of Euler equations is used for calculating the flowfield over a lifting rotor in hovering.To incorporate important effects of the rotor wake,the far-field boundary condition derived from the rotor momentum theory and the new wall boundary condition coupled with the rotor free wake are used.Embedded grids are adopted to weaken the numerical diffusion of the wake and to apply the above boundary conditions.Aiming at the key identification issue of donor elements in the embedded grids,a searching scheme,i.e.the Pseudo-Searching scheme of Donor Elements(PSDE) is presented.Numerical examples of the blade surface pressure and spanwise blade lift distributions are performed with and without wake corrections.Results are validated compared with the available experimental data.Finally,vorticity magnitude contours are computed and characteristics of the distorted rotor wake are analyzed.