Unsteady boundary layer transition experiments are performed in a modified Ludwieg tube setup. The transition is initiated by means of a moving bar mechanism which translates cylinders in front of a test plate. The intensity of the wakes shed by the cylinders is so large that transition starts at the leading edge. In streamwise direction the wake-induced transition area grows and keeps its initial shape. Also experiments are performed in which the moving cylinders are combined with a static grid. In the time between two wakes, individual turbulent spots develop which grow in streamwise direction. These spots merge with the wake-induced transition until a completely turbulent boundary layer is obtained. When the experimental results are transformed in intermittency distributions based on the turbulent-to-laminar time fraction, the superposition principle proofs to be applicable. However, the intermittency distribution based on the mean heat flux cannot be determined unequivocally. This is due to the fact that there does not exist a unique turbulent heat flux. This flux appears to be dependent on the origin of the transition.