Wake Signature of Finite-Span Flapping Rigid Wings

Abstract

A numerical study is conducted in order to investigate the wake signature and aerodynamics forces of finite-span flapping wings. The unsteady laminar incompressible Navier-Stokes equations are solved on moving overlapping structured grids using a second-order accurate in space and time finite-difference scheme. Specifically, finite-span rigid wings undergoing pure heaving and root-flapping motions are studied. From the results presented, it is found that root-flapping wings produce wake structures similar to those of heaving wings, but with the difference that the latter wing kinematics generates larger vortices and forces than root-flapping wings; aside from this, similar wake regimes occurs at comparable values of the Strouhal numbers. The numerical simulations are performed at a Reynolds number of Re=250 and at different values of Strouhal number and reduced frequency.