Modern aspects of high-reynolds-number asymptotics of turbulent boundary layers: From fully attached to marginally separated flows

Abstract

This contribution reports on recent efforts with the ultimate goal to obtain a fully self-consistent picture of turbulent boundary layer separation. To this end, it is shown first how the classical theory of turbulent boundary layers having an asymptotically small streamwise velocity deficit can be generalised rigorously to boundary layers with a slightly larger, i.e. moderately large, velocity defect and, finally, to situations where the velocity defect is of O(1). In the latter case, the formation of short recirculation zones describing marginally separated flows is found possible, as described in a rational manner.