Meeting Abstract

119.4  Saturday, Jan. 7  How aerodynamic induced power scales with body mass and wing span in British dragonflies and damselflies HENNINGSSON, Per*; BOMPHREY, Richard/J; University of Oxford; University of Oxford per.henningsson@zoo.ox.ac.uk

The efficiency with which a flying animal generates lift has wide ranging implications and impacts upon its maximum flight range, peak load lifting capacity, flight duration, accelerations during manoeuvres and other performance metrics that are dependent on energy budget. Some measures of aerodynamic efficiency can be directly measured using flow diagnostic techniques. Measuring the flow around insects in flapping flight presents an exciting challenge because they are typically small, have high wingbeat frequencies, and the aerodynamics can be highly time variant and complex. Nevertheless, if the flow fields they generate can be measured then the efficiency of the process can be assessed using well-established aerodynamic theory. We used high-speed stereo Particle Image Velocimetry (repetition rate 1 kHz) to measure the distribution of induced flow of freely flying species of damselflies and dragonflies flying in a wind tunnel and calculated the efficiency of lift production at many intervals during the stroke cycle. The species included in the study covered a three-fold range of wingspan, and a forty-fold range in mass. We present how time-varying span efficiency scales with size and mass in British Odonata over these ranges.