Implicit LES Computations with Applications to Micro Air Vehicles

Implicit large eddy simulation (ILES) computations have been performed for canonical model problems associated with flexible, flapping-wing micro air vehicles. This computationally intensive approach, which is able to directly model laminar/transitional/turbulent flowfields, requires the use of the best high performance computational platforms available. Computations are first performed for an SD7003 airfoil section at α_o=4° plunging with reduced frequency k=3.93 and amplitude h_o=0.05. For Re_c=4×10⁴, the dynamic-stall vortex system is laminar at inception, but experiences an abrupt breakdown associated with the onset of spanwise instability effects. The aerodynamics solver is then coupled with a nonlinear finite element solver to compute the flow over a flexible membrane wing. A description of the unsteady fluid/structure interaction for α=14° is presented indicating a close coupling between the unsteady flow behavior and the structural response. Good agreement of the computed results with available experimental measurements is shown for both problems considered.