通过数值模拟方法研究多段机翼的地面效应,采用有限体积法求解质量加权平均Navier-Stokes方程,湍流模型选用Spalart-Allmaras模型,利用运动壁面边界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,多段机翼的升力、阻力和低头力矩均减小;迎角、展弦比越大,地面效应越明显,升力损失越大;升力的减小主要是由于地面效应导致机翼下方静压增大的气流通过缝隙进入机翼上表面流场,使得机翼下翼面压力的增加量小于上翼面吸力的减小量;地面效应使机翼上翼面翼尖容易发生分离;翼尖涡沿着展向方向向外移动,机翼诱导阻力减小。该文研究结果可以为大型飞机的增升装置地面效应设计提供参考依据。

A multi-element wing operating in ground effect is investigated numerically. The compressible Navier-Stokes equations are solved by the finite-volume method. An Spalart-Allmaras turbulence model is used. The slipping wall is used to simulate the relative movement of the ground. The results indicate that, with a reduction in height, the lift, drag and node down moment of the multi-element wing decrease. The ground effect is more obvious with greater angles of attack and aspect ratios, and the lift losses also become greater. The effect of the sweep angle on the ground effect is small. The cause of the reduction of lift is that the losses of the suction side of the upper surface are greater than the increases of the pressure side of the lower surface. Adverse gradient increases on the upper surface of the wing in ground effect may cause the flow to separate near the wing tip. Tip vortex goes downstream outward along the span direction, and the induced drag of the wing decreases. The results of the simulation may provide a theoretical basis for the design of height lift devices of large aircraft in ground effect.