School of Mechanical Engineering, Purdue University, 500 Allison Rd., Chaffee Hall, West Lafayette, IN 47907, USA.
Bioinspir Biomim. 2009 Dec;4(4):046003. doi: 10.1088/1748-3182/4/4/046003. Epub 2009 Nov 17.
We investigated inertial and aerodynamic power consumption during hovering flight of the hawk moth Manduca sexta. The aerodynamic power was estimated based on the aerodynamic forces and torques measured on model hawk-moth wings and hovering kinematics. The inertial power was estimated based on the measured wing mass distribution and hovering kinematics. The results suggest that wing inertial power (without consideration of muscle efficiency and elastic energy storage) consumes about half of the total power expenditure. Wing areal mass density was measured to decrease sharply from the leading edge toward the trailing edge and from the wing base to the wing tip. Such a structural property helps to minimize the wing moment of inertia given a fixed amount of mass. We measured the aerodynamic forces on the rigid and flexible wings, which were made to approximate the flexural stiffness (EI) distribution and deformation of moth wings. It has been found that wings with the characteristic spanwise and chordwise decreasing EI (and mass density) are beneficial for power efficiency while generating aerodynamic forces comparative to rigid wings. Furthermore, negative work to aid pitching in stroke reversals from aerodynamic forces was found, and it showed that the aerodynamic force contributes partially to passive pitching of the wing.
我们研究了 Hawk 蛾属六翅目昆虫悬停飞行时的惯性和空气动力功耗。基于模型 Hawk 蛾翅膀的空气动力和力矩以及悬停运动学，估算了空气动力功率。基于测量的翅膀质量分布和悬停运动学，估算了惯性功率。结果表明，（不考虑肌肉效率和弹性储能）翅膀惯性功率约占总功耗的一半。翼面质量密度从前缘向后缘以及从翼根向翼梢急剧减小。这种结构特性有助于在给定的质量下最小化机翼的转动惯量。我们测量了刚性和柔性机翼上的空气动力，这些机翼的设计旨在近似模拟蛾类翅膀的弯曲刚度（EI）分布和变形。结果表明，具有特征性的沿展向和沿弦向减小 EI（和质量密度）的机翼有利于在产生空气动力时提高功率效率，与刚性机翼相比具有优势。此外，在反向冲程中发现了有助于俯仰的负功，这表明空气动力部分有助于机翼的被动俯仰。
