Boundary Layer Theory

References:

1. Chapter 17 Fundamentals-of-AerodynamicsJohn-D.-Anderson-Jr-2010
2. Abbott & von Doenhoff, Theory of Wing Sections
3. Schlichting, H. (1968) Boundary-Layer Theory, McGraw-Hill, New York
4. White, F. M. (1991) Viscous Fluid Flow, McGraw-Hill, New York 

Boundary layer properties

Boundary layer

The boundary layer is the thin region of flow adjacent to a surface, where the flow is retarded by the influence of friction between a solid surface and the fluid

Displacement thickness

Displacement thickness is the distance by which an external flow streamline is displaced by the presence of the boundary layer