Transition control of hypersonic boundary layer through non-uniform surface temperature distribution*

The location point of laminar to turbulent transition in hypersonic boundary layers has a significant influence on viscous drag and aerodynamic heating of external surfaces of hypersonic vehicles. This is a dominant source of uncertainties during the design process, and it motivates further research on transition control.

Previous work investigated the stabilization of hypersonic boundary layers by optimally growing streaks. More recently, a highly tuneable, practical implementation of this control method has been proposed through the use of smart surfaces that exploit the thermodynamic characteristics of the surface material, and the high heat flux typical of hypersonic flows.

In this work, compressible direct numerical simulations of a hypersonic boundary layer over a flat plate are used to assess the effect of streaks on laminar to turbulent transition. This work opens new routes to passive transition control through manipulation of the surface temperature. The method promises significant improvement on the aero-thermal-structural efficiency of hypersonic vehicles.