Biomimetic Flow Control

Biologic flight has undoubtedly intrigued man for thousands of years, yet it has been only the last 100 years or so that any serious challenge has been mounted to the pre-eminence of birds. Although present-day large-scale aircraft are now clearly able to fly higher, faster and farther than any bird or insect, it is obvious that these biological creatures have a mastery of low Reynolds number, unsteady flows that is unrivaled by man-made systems. This paper suggests that biological flight should be examined for mechanisms that may apply to engineered flight systems, especially in the emerging field of small-scale, uninhabited aerial vehicles (UAV). This paper discusses the kinematics and aerodynamics of bird and insect flight, including some aspects of unsteady aerodynamics. The dynamics of flapping wing flight is briefly examined, including gait selection, flapping frequency and amplitude selection, as well as wing planform and angle-of-attack dynamics. Unsteady aerodynamic mechanisms as practiced by small birds and insects are reviewed. Drag reduction morphologies of birds and marine animals are discussed and fruitful areas of research are suggested.