A numerical study of transonic buffet on a supercritical airfoil

Abstract

The steady/unsteady flow of the BGK No. 1 supercritical airfoil is investigated by the solution of the Reynolds-Averaged Navier-Stokes equations with a two-equation k-ω turbulence model. The dual-time stepping method is used to march in time. Two steady cases (Ma = 0.71, α = 1.396° and Ma = 0.71, α = 9.0°) and one unsteady case (Ma = 0.71, α = 6.97°), both with a far-stream Re = 20×10 6, are computed. The results are compared with experimental data obtained by Lee et al. The mechanism of the self-excited oscillation for supercritical airfoils is explored. The oscillation period calculated based on the mechanism proposed by Lee is consistent with the Fourier analysis of the computed lift coefficient.