ABSTRACT
Hypersonic flight is characterized by very high values of temperature and heat flux reached at the wall, which can compromise the structural integrity of the vehicle. This is due to the large amount of kinetic energy converted into thermal energy by the shock forming in front of the body and by viscous effects inside the boundary layer. This produces high temperature peaks inside the boundary layer at small normal distances from the wall, which results in a high wall heat flux. In order to understand the heat-exchange mechanism between the flow and the wall and to predict the temperature levels and heat load to which the vehicle surface is exposed, it is necessary to consider the main thermal characteristics of a hypersonic boundary layer. The cooling techniques considered for the thermal protection system of hypersonic vehicles can be divided into two main classes, namely, active cooling and passive cooling.
