Invisid flow about a blunt object involves limiting to 0 viscosity. There should be 0 drag according to the theory, but there is significant drag. There is a boundary layer.

The boundary layer tends to seperate from the object when the cross section of the object decreases. In order to avoid momentum loss by the object it is desirable to keep the boundary layer next to the object as long as possible. Methods:

• streamlining
• inducing turbulence
• drag crises

source psfile jl@crush.caltech.edu index laminary_boundary laminar_boundary drag_crises