Effect of lateral, downward, and frontal gusts on flapping wing performance

The effect of lateral, downward, and frontal wind gusts on the aerodynamic characteristics of a rigid wing undergoing insect-based flapping motion is studied numerically. The turbulent flow near the flapping wing is described by the 3-D unsteady compressible Reynolds-Averaged Navier-Stokes equations with the Spalart-Allmaras turbulence model. The governing equations are solved using a second-order node-centered finite volume scheme on a hexahedral body-fitted grid that rigidly moves along with the wing. A low-Mach-number preconditioner is used to accelerate the convergence of subiterations at each time step. Our numerical results show that the aerodynamic response of the centimeter -scale wing to various gust conditions strongly depends on the mutual orientation of the wing stroke plane and the gust velocity vector.