Aerodynamic Characteristics of Rotating Beetle Wings

Ariel insects, a low Reynolds number flyer, feature various flight mechanisms (flapping wings, multiple wings motions, etc.). Insects’ wings are configured in various forms over the body, with different shapes and proximities to each other. When an insect flap its wings, it generates two distinct wakes: one from each of its wings. If the wings are located closely, their proximity will cause an interaction between the two wakes in the near field. One open question is: How does this interaction affect aerodynamic loads as well as the wake flow dynamics, during forward flight? We study this flight mode, at low Reynolds numbers and body/wing ratio, by using a rotating wing reference frame to perform controlled experiments that will simulate the motion. With a set of wings locked to the same axis and planar height, the effect of the wake generated by one wing on another can be observed. Experiments were performed using a 3D-PTV (particle tracking velocimetry) system in a closed glass chamber where an electrical motor was used to rotate a set of beetle wings. Using a 3D system allows for measuring of all velocity components of the flow around the rotating wings creating a volume of information. The beetle wings used in the experiments were from the species Batocera rufomaculata. This species has several morphological features that can be altered to perform ample experimentation such as size of the wings and angle of attack (AoA). By characterizing the aerodynamic performance, understanding of the impact of wing orientation (i.e., AoA), wing size, and distance between wings on the wake-flow dynamics and their interactions (i.e.: constructive or destructive) can be achieved.