ABSTRACT The present study numerically investigates the aerodynamic characteristics of two-dimensional wings in the vicinity of the ground by solving two-dimensional steady incompressible Navier-Stokes equations with the turbulence closure model of the realizable k-ε model. Numerical simulations are performed at a wide range of the normalized ground clearance by the chord length (0.1≤h/C ≤ 1.25) for the angles of attack (0° ≤ α ≤ 10°) in the pre-stall regime at a Reynolds number (Re) of 2×10 6 based on free stream velocity U ∞ and the chord length. As the physical model of this study, a cambered airfoil of NACA 4406 has been selected by a performance test for various airfoils. The maximum lift-to-drag ratio is achieved at α = 4° and h/C = 0.1. Under the conditions of α = 4° and h/C = 0.1, the effect of the Reynolds number on the aerodynamic characteristics of NACA 4406 is investigated in the range of 2× 10 5 ≤ Re ≤ 2× 10 9 . As Re increases, C l and C d augments and decreases, respectively, and the lift-to-drag ratio increases linearly.
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机译：摘要本研究通过用可实现的k-ε模型的湍流闭合模型求解二维稳态不可压缩Navier-Stokes方程，对地面附近二维机翼的空气动力学特性进行了数值研究。在雷诺数下在失速前状态下迎角（0°≤α≤10°）的迎角（0°≤α≤10°）的弦长（0.1≤h/ C≤1.25）的大范围归一化离地间隙上进行数值模拟基于自由流速度U∞和弦长的（Re）为2×10 6。作为这项研究的物理模型，通过性能测试为各种翼型选择了NACA 4406弧形翼型。在α= 4°和h / C = 0.1时达到最大升阻比。在α= 4°和h / C = 0.1的条件下，研究了雷诺数对NACA 4406空气动力学特性的影响，范围为2×10 5≤Re≤2×10 9。随着Re的增加，C l和C d分别增加和减少，并且升阻比线性增加。
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