论文标题
低估比率扫式翅膀的空气动力学表征$ re = 400 $
Aerodynamic characterization of low-aspect-ratio swept wings at $Re=400$
论文作者
论文摘要
我们执行不稳定的三维直接数值模拟，以研究有限态度的回合翼的空气动力学特征，并以NACA 0015横截面为基于和弦的雷诺数为400。有限态度比例翼（$ sar = 0.5 $，1和2）在较大的攻击角度（$α= 0^{\ circ} -30^{\ circ} $）。相对于这些参数，不稳定的层流分离流具有复杂的空气动力学特征。由于中跨附近的涡流结构产生的升降机，扫描的引入可增强较低纵横比的翅膀升降机。在这些情况下，阻力系数对扫角的依赖性较低，尤其是在较低的攻击角度。低估翅膀的吊式比率随扫角而增加。但是，对于具有较高纵横比的机翼，扫角对升力系数和提升比率的这种有利影响没有观察到，在翼范围内中跨效应相对较弱。本文的结果提供了低估翅膀的层流空气动力学表征，并补充了不稳定的低雷诺 - 空气空气动力学数据库，并亮点了扫描效果。
We perform unsteady three-dimensional direct numerical simulations to study the aerodynamic characteristics of finite-aspect-ratio swept wings with a NACA 0015 cross-section at a chord-based Reynolds number of 400. The effects of the sweep angle ($Λ=0^{\circ}-45^{\circ}$) on the aerodynamic force coefficients are examined for finite-aspect-ratio wings ($sAR=0.5$, 1, and 2) over a wide range of angles of attack ($α=0^{\circ}-30^{\circ}$). The unsteady laminar separated flows exhibit complex aerodynamic characteristics with respect to these parameters. The introduction of sweep enhances lift for wings with low aspect ratios of $sAR=0.5$ and 1, due to the lift generated by the vortical structures near the midspan. For these cases, the dependence of drag coefficients on the sweep angle is less noticeable, particularly at lower angles of attack. The lift-to-drag ratios for low-aspect-ratio wings increase with the sweep angle. However, such favorable effects of sweep angle on the lift coefficients and lift-to-drag ratios are not observed for wings with higher aspect ratios, where the midspan effects are relatively weaker over the wing span. The results herein provide a laminar aerodynamic characterization of the low-aspect-ratio wings and complement the unsteady low-Reynolds-number aerodynamic database with highlight on the effect of sweep.
