多段翼型地面效应数值模拟与分析

Numerical simulation and analysis on aerodynamics of three-element airfoil in ground effect

通过数值模拟方法研究多段翼型的地面效应,采用有限体积法求解质量加权平均平均Navier-Stokes(N-S)方程,湍流模型采用Spalart-Allmaras(S-A)模型,采用滑移壁面模拟地面的相对运动.计算结果分析表明:随着飞行高度的降低,多段翼型的升力、阻力和低头力矩均减小;升力系数的减小主要是由于地面效应引起流场改变,下翼面压力的增加量小于上翼面吸力的减小量引起;地面效应使翼型上表面逆压梯度增加,后缘襟翼容易出现分离.

A three-element airfoil operating in ground effect was investigated numerically.The compressible Navier-Stokes equations were solved by the finite-volume method.Spalart-Allmaras（S-A） turbulence model was used.Slipping wall was used to simulate the relative movement.The effects of flight height on the aerodynamics of the multi-element airfoils were found obviously as compared with clean airfoils.The results indicate that,with the reduction in height,the lift increases for the multi-element airfoil,but decreases for the clean airfoil,while the drag and nose down moment decrease for both airfoils.The cause of the reduction of lift lies in that,the losses of suction at upper surface are more than the increases of pressure at lower surface.The separated region becomes larger with the decline of the height.