论文标题
猫头鹰机翼的前缘锯齿的3D曲率通过3D曲率控制流动效应和层流效果
Flow turning effect and laminar control by the 3D curvature of leading edge serrations from owl wing
论文作者
论文摘要
这项工作描述了带有梳状前缘装置的向后扫向机翼的层流控制的新机制。它的灵感来自猫头鹰羽毛上的前沿梳子和倒钩的特殊设计，类似于一系列复杂的3D曲线薄膜。猫头鹰羽毛的倒钩几何形状的细节用于设计梳子的通用模型，用于实验和数值流量研究，并与梳子连接到平板的前缘。检查是在不同的扫角进行的，因为生命动物在滑行和拍打过程中清楚地显示了机翼的向后扫掠。结果表明，边界层内部的流动转向效果，该板沿倒钩长度倍数的距离沿和弦延伸。因此，此处描述的板内流动效果应对向后扫向翼的舷外跨跨跨跨流动。从对扫描机翼的最新理论研究来看，已知在边界层中转动流量的方式可以减弱交叉流量的不稳定性和延迟过渡。梳子诱导的跨跨速度曲线与被证明延迟过渡的梳子式跨速度曲线的比较显示出极好的一致性，这支持了层流流控制假设。因此，预计观察到的效果将延迟猫头鹰飞行的过渡，从而导致更加沉默的飞行
This work describes a novel mechanism of laminar flow control of a backward swept wing with a comb-like leading edge device. It is inspired by the leading-edge comb on owl feathers and the special design of its barbs, resembling a cascade of complex 3D-curved thin finlets. The details of the geometry of the barbs from an owl feather were used to design a generic model of the comb for experimental and numerical flow studies with the comb attached to the leading edge of a flat plate. Examination was carried out at different sweep angles, because life animal clearly show the backward sweep of the wing during gliding and flapping. The results demonstrate a flow turning effect in the boundary layer inboards, which extends along the chord over distances of multiples of the barb lengths. The inboard flow-turning effect described here, thus, counter-acts the outboard directed cross-span flow typically appearing for backward swept wings. From recent theoretical studies on a swept wing, such a way of turning the flow in the boundary layer is known to attenuate crossflow instabilities and delay transition. A comparison of the comb-induced cross-span velocity profiles with those proven to delay transition in theory shows excellent agreement, which supports the laminar flow control hypothesis. Thus, the observed effect is expected to delay transition in owl flight, contributing to a more silent flight
