DNS of Complete Transition to Turbulence Via Oblique Breakdown at Mach 3: Part II

The nal stage of transition to turbulence in a supersonic at-plate boundary layer at Mach 3 is investigated using Direct Numerical Simulations (DNS). A set of six simulations was performed to study the development of a pair of oblique waves from their initiation at low amplitudes to nal breakdown to turbulence. In a previous paper (part I of this study), the linear and early nonlinear regimes of this so-called "oblique breakdown scenario " were discussed. The focus of the present paper (part II) is on the early turbulent regime, i.e. the region of the ow downstream of the maximum of skin friction. In this region, the ow is shown to have lost periodicity in time and to exhibit the typical mean ow and spectral properties of a turbulent boundary layer as known from the literature and theory. The DNS data clearly demonstrate that oblique breakdown can lead to a fully developed turbulent boundary layer and therefore may be a relevant mechanism for practical applications. I