93-6 Wednesday, Jan. 6 14:45 Snakes in a Cube: high-resolution kinematics of gliding in flying snakes YEATON, I.J.*; BAUMGARDNER, G.A.; WEISS, T.M.; NAVE, G.; ROSS, S.D.; SOCHA, J.J.; Virginia Tech; Virginia Tech; Virginia Tech; Virginia Tech; Virginia Tech; Virginia Tech firstname.lastname@example.org http://www.thesochalab.org
Gliding by flying snakes of the genus Chrysopelea is distinguished by complex, three-dimensional body undulations. Undulation may enhance lift, as it places a greater percentage of the body perpendicular to the flow, but it may also be destabilizing, as unsteady aerodynamic forces are constantly redistributed over the body. Quantifying the undulation waveform is therefore necessary to determine the contributions of aerodynamic and inertial effects on stability. However, previous experimental studies under-resolved the undulation waveform during gliding. Here, we report on recent glide experiments for two species of Chrysopelea to improve the temporal (6X) and spatial (4X) measurement resolutions of the body, and to provide the first measurements of tail motion. We recorded a total of 97 glides from 7 individuals of C. paradisi and 34 glides from 5 individuals of C. ornata in a large indoor arena (“The Cube” at Virginia Tech). Snakes were marked with between 12 and 17 landmark points along the trunk and tail, and allowed to jump and glide from a height of 8.5 m. Landmark points were tracked using a 23-camera motion-capture system (179 fps, Qualisys Oqus 500) and two high-speed cameras (500 fps, Photron APX-RS). We reconstructed body posture throughout the glide by fitting arc-length constrained quintic splines to the measured points and calculating the curvature and torsion. C. paradisi had better overall glide performance and more uniform lateral undulation than C. ornata. Supported by NSF 1351322.