THE EFFECTS OF A FAVORABLE PRESSURE-GRADIENT AND OF THE REYNOLDS-NUMBER ON AN INCOMPRESSIBLE AXISYMMETRICAL TURBULENT BOUNDARY-LAYER - PART2 - THE BOUNDARY-LAYER WITH RELAMINARIZATION

This is an experimental investigation of two turbulent boundary layers (cases 2 and 4) where the streamwise negative pressure gradient chang es mean properties of the flow, e.g. mean velocity profiles and skin f riction, so that they display laminar-like behaviour. The maximum acce leration parameter K less than or equal to 4 x 10(-6) and the starting value of the Reynolds number is 862 or 2564. Relaminarization occurs in both boundary layers as a gradual change of the turbulence properti es and is not catastrophic. Retransition, however, is a fast process d ue to the remaining turbulence structure and may be compared with bypa ss transition. Together with an extensive investigation of the turbule nce structure as in the companion paper, Part 1, which describes two c ases (1 and 3) of boundary layers which remain turbulent, spectra and integral length scales for all four boundary layers are discussed.