Influence of forward-facing steps on laminar-turbulent transition

The influence of forward-facing steps on laminar-turbulent transition is investigated by means of numerical methods. The context for the present work is the development of a future laminar wing. An important step in the development process is the quantification of the influences of surface imperfections on the transition location. Until now, the effect of steps on laminar-turbulent transition in realistic in-flight conditions was either investigated by experiments or by linear stability theory (LST). In the present study, direct numerical simulation (DNS) and LST are used to calculate additional amplification factors ∆N, based on the eN-method. This ∆N-factor quantifies the influence of a step on the transition location. Both the generic case on a plate without pressure gradient as well as the case with pressure gradient on an airfoil are studied.