Later Stages of Boundary-Layer Transition

The need for understanding and predicting the laminar-turbulent transition is imperative in many technologically important situations. The National Aerospace Plane, the Advanced Subsonic Transport, and the High Speed Civil Transport are but a few examples in which the vehicle dynamics are modulated by the transition process. The onset of transition controls whether the flow over an aircraft wing is laminar or turbulent and determines whether the flow will remain attached, become fully separated, or form a separation bubble and reattach. Drag reduction in external or internal flows depends on the detail of the transition process, and efforts to predict heat transfer and to cool the turbulent blades are hampered by lack of a reliable transition scheme. The present chapter discusses boundary-layer transition with emphasis on the incompressible case.