Effect of Trailing-Edge Morphing on Flow Characteristics Around a Pitching Airfoil

Abstract

This paper investigates suppressing the pitching oscillation of a NACA 0012 airfoil at a Reynolds number of [Formula: see text] by using phase-shifted trailing-edge morphing. The latter considering geometric nonlinearity is simulated numerically based on spatiotemporal polynomial surface fitting. Flowfield results and aerodynamic forces are obtained by solving the unsteady Reynolds-averaged Navier–Stokes equations accompanied by a low-Reynolds-number modified-shear-stress transport model. Dynamic meshing combining a sliding mesh and Laplacian diffusion is developed to deal with the deformation of the computational grid due to the large-amplitude coupled pitching and morphing motion of the airfoil. The airfoil is subjected to stall-flutter analysis from an energy perspective by calculating the energy extracted by the airfoil from the freestream in an oscillation cycle. The flow control mechanism of the phase-offset trailing-edge morphing is analyzed in terms of the pressure distribution and moment contribution. The results suggest that trailing-edge motion with a phase of [Formula: see text] reduces the energy extraction by more than 300% and could be effective for suppressing the stall-flutter limit-cycle oscillation amplitude in specific ranges of amplitude and frequency.