Numerical Simulation of Transition in Hypersonic Boundary Layers
Final rept. 1 Apr 2008-30 Nov 2010
ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
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The laminar-turbulent transition process in supersonic and hypersonic boundary layers was investigated using spatial and temporal Direct Numerical Simulations DNS. Our previous research indicated that oblique breakdown might be a highly relevant nonlinear mechanism for supersonic boundary layers. However, a nonlinear mechanism would only be relevant for the transition process if this mechanism can lead to fully developed turbulence. Hence, to address this question, the late nonlinear transition regime of a supersonic flat-plate boundary layer at Mach 3 was studied using spatial DNS. These simulations demonstrated that a fully turbulent flow can develop via oblique breakdown. We also investigated the nonlinear disturbance development in a hypersonic boundary layer on a sharp circular cone at Mach 8 using spatial and temporal DNS. It was confirmed in these simulations that fundamental resonance and oblique breakdown are the viable paths to transition in hypersonic boundary layers.
- Fluid Mechanics