Gowree Erwin R, Tome Joao Dinis, Escamilla Alejandro Dominguez, Bauerheim Michael
Department of Aerodynamics, Energy and Propulsion, ISAE-SUPAERO, Toulouse, France.
Sci Rep. 2025 Apr 30;15(1):15140. doi: 10.1038/s41598-025-97990-5.
From classical mechanics the lift coefficient, [Formula: see text], required during the final stage of the pull-out manoeuvre of raptors is significantly larger than those provided under static pitch condition at equivalent angle of attack. Using data from observation in live experiments and wind-tunnel on static models, coupled with our current numerical study, we demonstrated that the high lift is achieved through dynamic pitching while engaging into the pull-up. Computational fluid dynamics (CFD) simulations using a direct numerical simulation (DNS) approach with a Lattice-Boltzmann method (LBM), as well as unsteady Reynolds Averaged Navier-Stokes (URANS) simulations were performed over a [Formula: see text] swept non-slender delta wing, inspired by previous studies which showed that the flow over Peregrine falcons is dominated by large vortical structures. Here we show that, raptors potentially engage into dynamic pitching to meet the [Formula: see text] requirement under load factors n > 1 in order to achieve the high lift coefficient required during pull-up. Whilst it is a well-established fact for pitching wings, to our knowledge, this has not been extended to the observations in nature and could be therefore extended for application on nature inspired autonomous aerial vehicles or systems.
根据经典力学，猛禽在拉起动作的最后阶段所需的升力系数[公式：见正文]，比在相同攻角下静态俯仰条件下的升力系数要大得多。利用现场实验和静态模型风洞观测数据，结合我们目前的数值研究，我们证明了在拉起过程中通过动态俯仰可实现高升力。采用格子玻尔兹曼方法（LBM）的直接数值模拟（DNS）方法以及非定常雷诺平均纳维-斯托克斯（URANS）模拟，对一个[公式：见正文]后掠非细长三角翼进行了计算流体动力学（CFD）模拟，此前的研究表明游隼上的气流主要由大型涡结构主导，本研究受其启发。我们在此表明，猛禽可能会进行动态俯仰，以满足载荷因子n > 1时的[公式：见正文]要求，从而实现拉起过程中所需的高升力系数。虽然俯仰机翼这一事实已得到充分证实，但据我们所知，这尚未扩展到对自然界的观测中，因此可扩展应用于受自然启发的自主飞行器或系统。
