Different approaches to asymptotic expansions in turbulent boundary layers

The present approach to matched asymptotic expansions in turbulent flow is based on a systematic application of the Millikan-Kolmogorov hypothesis, and leads to functional equations in appropriate overlap domains. The solution of these equations, and the consistent application of an associated procedure, have led to useful results for a wide variety of turbulent flows, which are often suggestive of unsuspected relationships between associated parameters. Attention is given to the functional equation approach