In this paper the behavior of a turbulent boundary layer perturbed from its equilibrium state, due to the presence of an obstacle on an otherwise smooth surface, was investigated. The data of the equilibrium turbulent boundary layers are presented in terms of dimensionless integral parameters, where the flow features can be simply estimated. It was found that the rate of recovery to equilibrium, at highly adverse pressure gradients, is almost instantaneous in the inner part of the new boundary layer initiated by the reattachment process. The flow recovery downstream of an obstacle is correlated in term of Clauser’s profile parameter ratio,G/G′. ©1996 American Institute of Physics.