An aerodynamic evaluation of insect wing shapes and kinematics optimised for efficiency or effectiveness

Many constraints act on selection of wing planform shape and kinematics (motion) for insects including aerodynamics, physiology and body configuration. The primary constraint is understood to be driven by aerodynamic performance; however, understanding in this area remains incomplete. This presentation evaluates the aerodynamic performance of a variety of insect wings using a quasi-steady aerodynamic model recently developed by the authors. The aim is to understand the degree to which designs in nature are optimal with respect to aerodynamic performance. Two aspects of aerodynamic performance are considered: the effectiveness of the wing (what is the maximum aerodynamic force that can be generated), and the efficiency (how much power is required to generate a given amount of lift). Analytical solutions derived for optimal planform shapes and kinematics are compared with those of a range of species. It is shown that, for example, the wing planform of the fruit fly is more biased towards effectiveness, rather than efficiency. Alternatively, the wing planform and kinematics of a hummingbird (as a surrogate for an insect that hovers whilst feeding) is shown to be biased more strongly towards the theoretical shape most adapted to efficient flight.