Numerical investigation of pitching airfoil subjected to incoming gust

This work investigates the aerodynamic and acoustic response of a pitching airfoil subjected to time-harmonic gust flows. A low-dissipation and dispersion numerical solver of compressible Navier–Stokes equations was developed with the kinetic energy preserving flux scheme. The incoming gust perturbations were introduced via the momentum source method. Then, the interaction between a gust and a pitching airfoil is subsequently analyzed. In the absence of incoming gusts, the wake of the airfoil is composed of a series of vortex pairs convected downstream, while the lift and drag curves exhibit stable periodic variations. The presence of the gust has significant impact on the wake structure and aerodynamics of the pitching airfoil. Specifically, when the gust has a small wavenumber, the phase of the gust significantly influences the far-field sound. Interestingly, the symmetry of the lift and drag curves, as well as the wake structure, varies with the wavenumber of the incoming flow. The phase angle of the inflow gust also impacts the wake pattern and the aeroacoustics of the pitching airfoil evidently. A gust with a smaller amplitude has minor effects on the aerodynamics and aeroacoustics of the pitching airfoil.