Meeting Abstract

97.1  Saturday, Jan. 7  A theoretical investigation of static stability in gliding snakes JAFARI, F.*; SOCHA, J.J.; Virginia Tech jafari@vt.edu

Flying snakes undulate while gliding, using their entire body as a continuously morphing ‘wing’ to produce flight forces. Studies of static 2D airfoils using the snake’s aerial cross-sectional shape have demonstrated that this shape maintains high lift at angles of attack as large as 35&deg. However, the unsteady effects of undulation on gliding in flying snakes has never been studied. In particular, the role of the highly dynamic postural reconfiguration in the control system is unknown; how the snake remains stable in the pitch, roll and yaw directions is not understood. Whereas the simplest hypothesis posits that the snake is passively stable in all directions, active control may indeed be required about all axes. Here, we developed a theoretical model to investigate the transient motions and stability characteristics of an airborne flying snake. This two-dimensional model was developed in a way to simulate dynamics in the configuration space resembling the behavior of an aerially undulating snake. Previously obtained experimental aerodynamic data were incorporated into the model, and undulation was modeled by varying area and mass distribution. Bilateral symmetry was assumed to allow decoupling of the motions in the longitudinal and lateral directions. Stability (considered quasi-statically) in the pitch axis was examined by testing the proposed model against the static stability criterion. Additionally, we used this model to test the hypothesis that, given enough time, equilibrium gliding could be achieved.