领尖曲效应在悬浮和前进飞行中对动翅膀的空气动力性能产生影响
Reynolds Addo-Akoto1, Jong-Seob Han2, Jae-Hung Han1
1Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, Republic of Korea.
Bioinspiration & biomimetics
|July 2, 2024
概括
领尖曲率对平均升力和阻力的影响最小,但在羽翼动下降时可以增强升力. 这种效应在悬浮飞行中最为明显,并且与机翼的旋动力学有关.
科学领域:
- 流体动力学 流体动力学
- 空气动力学 航空动力学
- 生物启发的工程是生物启发的.
背景情况:
- 翅飞行对于许多昆虫和小型飞机至关重要.
- 了解翅膀几何学的影响,如前沿曲率,是提高空气动力学效率的关键.
- 之前的研究已经探讨了各种翅膀参数,但前沿曲率在不同飞行模式中的具体作用仍未得到充分研究.
研究的目的:
- 为了研究前端 (LE) 曲率对翼空气动力学的影响.
- 分析LE曲率在不同的前进比率 (J) 下的影响,从悬浮 (J=0) 到前进飞行 (J=1.0).
- 阐明导致任何观测到的空气动力学变化的潜在流动机制.
主要方法:
- 使用了一个缩放的机器人模型,通过机架轮车系统进行受控的前进运动.
- 改变了前进比 (J) 从0到1.0以模拟悬浮和前进飞行条件.
- 采用相锁平面数字粒子图像速度测量 (PIV) 进行详细的流动可视化和分析,包括远距离观察.
主要成果:
- 前沿曲率对周期平均空气动力学升力和阻力没有显著影响.
- 在下行中段期间观察到提升系数的显著提高,随着前进比率 (J) 的增加而下降.
- 流量分析显示,LE曲率主要有利于机翼外侧部分,通过增强循环,与较少拉伸的前边 (LEVs),减弱的后边 (TEVs) 和连贯的尖端 (TV) 融合相关.
结论:
- 领航边缘曲率对整体翼性能的影响有限,但可以在向下冲击时提供升力,特别是在悬空时.
- 空气动力学的好处归因于改善的旋动力学,特别是增强了船外部分的循环和修改的尾道结构.
- 研究结果支持自然飞行员在研究的雷诺兹数范围 (10^3到10^4) 内的翅膀尖附近有轻微曲的近直前边的普遍性.
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