ABSTRACT
The basic aim of the material in this chapter is to acquaint readers with the state of the art in the study of receptivity and relate the same with instability and transition of fluid flow. This subject area remains the pacing item in understanding many natural phenomena, as well as in the analysis and design of many engineering systems. For example, this is pursued in civil aviation to design newer lifting surfaces with drag reduced by passive means. In this context, keeping the flow laminar (stable) over a wing, to as large an extent as possible, is the primary goal. With reduced drag, the aircraft speed and range can be increased for the same power consumed or have a less powerful engine for the same endurance and range of the flight envelope.
