Meeting Abstract
A reduced-order computational model that simulates the dynamics of complex animal flight maneuvers is introduced. The body of the animal is treated as a rigid mass connected to two wings and is free to translate and rotate. Each wing is represented by an assembly of short segments with a unique length, orientation and mass. In this way we can model non-planar wing morphologies that can not only flap and pitch, but can also perform complex motions such as twisting and folding. At present, the wing kinematics are prescribed and the model computes both inertial and aerodynamic forces and torques. Blade element momentum theory is used to estimate aerodynamic forces and torques on each wing segment. The wake is modeled using actuator disk theory so that the computed induced velocity field can be used to correct the effective angles of attack. The resultant inertia of the wing and the fluid (the added mass), along with the aerodynamic forces are used as inputs to a Lagrangian equation which computes the animal’s translation and rotation. Finally, an optimization scheme finds the kinematics required to execute a wingbeat cycle with minimum energy expenditure under imposed constraints of overall body translation and rotation. Equipped with this model, we are able to simulate a wide variety of flapping flight behavior representative of insect, bird, bat and bio-inspired robotic flight. We can also assess the relative roles of inertial and aerodynamic forces, and estimate power expenditures. Using symmetric wing motions, we study steady, level, climbing and descending flight as well as pitching maneuvers. Considering non-symmetric wing motions, we can also explore more complex maneuvers such as rolling and turning. In all cases, comparisons with previous simulations and with experimental observations are made.
