Instability of local supersonic regions over a flat-sided airfoil with a blunt trailing edge

Abstract

The two-dimensional turbulent transonic flow over a symmetric flat-sided airfoil with a blunt trailing edge is studied numerically. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained with a finite-volume solver on a fine computational mesh. The non-uniqueness of flow field in certain bands of the given free-stream Mach number and angle of attack is demonstrated. Intricate dependence of the lift coefficient on the free-stream parameters is discussed. Adverse free-stream parameters, which admit abrupt changes of the flow structure and lift, are identified.