Experimental evidence has shown that the transition process in a boundary
layer starts locally at a number of points, which are more or less randomly distributed
in both stream wise direction near the wall in region of finite stream wise extent at
some distance from the leading edge. These transitions probably occur because of
local instabilities of the mean basic flow to disturbances.
In this chapter, the transition from laminar to turbulent flow zone discussed physically
and theoretically. The stability of flow and their relation with disturbance of flow
presented in brief way.
The boundary layer velocity profile and all the related divination are derived by
assuming that the momentum thickness will remain constant across the transition
position.
Finally, the methods of boundary layer control to prevent separation in order to reduce
and attain nigh lift described.
Keywords: Boundary layer control, Momentum thickness, Stability of flow,
Transition flow zone.
