Impact of Forward-Facing Steps on Laminar-Turbulent Transition in Transonic Flows

The influence of forward-facing steps on the amplification of disturbances in transonic flows is studied numerically. The main goal is to find a function for an additional amplification factor N that can be incorporated into the eN method. In the present study, both two-dimensional direct numerical simulation of disturbances as well as linear stability theory are used to gain detailed information on the flow. Good agreement between N-factor results from direct numerical simulation and linear stability theory is obtained. Subsonic and slightly supersonic results show differences in the flow topology and in the shape of the N-factor curve, but effective N factors are in the same order of magnitude.