Transition studies on a two-dimensional NACA63 isolated airfoil at high Mach numbers

Experimental and numerical studies have been performed on the boundary layer transition process on an isolated NACA63 airfoil for varying inlet Mach numbers, incidence angles and free-stream turbulence levels. The experimental results show that for a free-stream turbulence of 0.3% and an inlet Mach number of 0.5, transition starts at about 60% chord for zero incidence and ends at about 85% chord. For increasing incidence, the suction side transition onset rapidly moves towards the leading edge and at 3 degrees incidence, the boundary layer is entirely turbulent. The pressure side transition onset moves towards the trailing edge for increasing incidence and the transition zone is prolonged. Increasing Mach number gives an earlier and shorter transition zone and increased turbulence intensity gives an earlier transition onset. The numerical investigation captures the same trend as the experiments, but fails to detect the same transition positions.