A CONTRIBUTION TO THE PHYSICAL ANALYSIS OF SEPARATED FLOWS PAST 3-DIMENSIONAL HUMPS

The aim of this article is to present a few improvements in the unders tanding of both mathematical and physical aspects of three-dimensional separated flows past a protuberance on a flat plate. Only steady lami nar incompressible hows are considered here. The asymptotic structure of boundary-layer flows with strong viscous-inviscid interaction has b een extensively studied by several authors, mainly with the triple-dec k theory. The first part of this paper presents the results of a syste matic analysis of the asymptotic structure when the obstacle's dimensi ons vary. This work explains why the triple-deck properties are so muc h characteristic. The three-dimensional boundary-layer equations are t hen solved with a quasi-simultaneous interacting technique, and the re sults are examined in order to describe the three-dimensional topology of the flow. Two types of flows are described, corresponding to a den t and a hump, that exhibit completely different behaviours. (C) Elsevi er, Paris.