Meeting Abstract

42.2  Tuesday, Jan. 5  Rotational flapping counter torque in insect flight CHENG, Bo*; DENG, Xinyan; Purdue University; Purdue University xdeng@purdue.edu

We studied the aerodynamic torque generation of flapping wings during roll, pitch and yaw rotations of the stroke plane. The counter torques generated by the wing pair due to body rotations were previously termed as flapping counter-torques (FCTs). For all three types of rotation, stroke-averaged FCTs are collinear with the rotation axes but opposite to the directions of rotation. Experiment results using dynamically scaled robotic wings shown that FCTs are linearly dependent on the flapping frequency and rotational velocity. For each type of rotation, we compared the measured FCT with the prediction of a mathematical model based on a quasi-steady analysis, where we show that FCTs can be explained by considering the asymmetries of wing velocity and effective angle of attack caused by each type of rotation. For roll and yaw rotations, our model provided close estimations of the stroke-averaged values. However, for pitch rotation, our model tends to underestimate the FCT, which may be largely affected by the unsteady aerodynamic mechanisms such as wake capture.