Meeting Abstract

P1.113  Tuesday, Jan. 4  Theoretical modeling of flying snake glide trajectories JAFARI, F.*; SOCHA, J.J.; Virginia Tech jafari@vt.edu

Gliding represents an efficient mode of locomotion for arboreal animals, but gliders must move through the air without losing control. Although most gliders create aerodynamic forces using static structures such as outstretched patagia to form ‘wings’, flying snakes (genus Chrysopelea) produce lift acting as a long, half-cylinder that continuously undulates during flight. Although the kinematics of snake gliding have been determined, the effects of body orientation and undulation on trajectory dynamics are not known. Here, we develop theoretical models to understand how flying snakes produce and control aerodynamic forces required for a stable glide. In a first model, we considered the snake to consist simply of three evenly spaced, coplanar rectangular segments oriented perpendicular to the air flow. To simulate the dynamics of undulation, these three segments changed length sinusoidally throughout the trajectory under the influence of gravity and aerodynamic forces. Lift and drag forces were calculated using coefficients determined from a previous physical modeling study. Under certain conditions, this model produced trajectories that resembled real snake glides. In other cases, the model failed, producing only ballistic trajectories. Additionally, when pitching rotation was allowed, the model failed due to instability, suggesting that real snakes require active control movements in the pitch axis. These models provide a first step to understanding how snakes produce controlled glides; future models will incorporate greater details of the snake’s complex motion and form. Research supported by DARPA (W911NF1010040).