Boundary Layer Receptivity: A Retrospect

Transition from laminar to turbulent flow in a boundary layer is of fundamental and practical importance, and as a result has been widely studied. Receptivity is the first stage of the transition process. The term receptivity was first used by Morkovin (1969) to describe the mechanism by which energy from the free stream enters and excites instability waves inside the boundary layer. Due to important role of receptivity theory in transition process of boundary layers, quite a few research works have been carried out in past few decades. This research review report tries to highlight the major research activities in this field of study that includes: the theory, different types of receptivity, its effect in three-dimensional boundary layers and receptivity at high speeds.