ABSTRACT
Boundary layers are regions in which a rapid change occurs in the value of a variable. Some physical examples of situations where boundary layers may occur are: the fluid velocity near a solid wall, the velocity at the edge of a jet of fluid, the temperature of a fluid near a solid wall, solute concentration near an interface condensing vapor on a cool surface. The thermal boundary layer was associated with a uniform velocity field. Usually both a momentum and thermal boundary layer must be considered. It is possible to predict the thickness of the momentum and thermal boundary layers by an algebraic method based on orders of magnitude estimates. This chapter explores how the Prandtl's Matching Condition is refined to deal with higher order matching. It describes the model problem to consider the nature of higher order terms in the inner and outer expansions and develop a matching condition.
