Nonequilibrium radiative hypersonic flows: Aerospace applications

Hyperenthalpic flows are encountered when spatial vehicules reenter the atm osphere (Anderson 1989) or in some astrophysical situations as in envelopes of cool pulsating stars (Lafon 1991). In reentry applications, a bow shock is created at the front of the vehicule. The plasma in the shock layer is highly collisional and the radiative heat flux is of the same order of magn itude as the convective heat flux. It is then necessary to take into accoun t the coupling between aerodynamics and radiation. For high mach numbers, electronic collisional processes are out of equilibr ium, and each atomic electronic level has to be considered as a distinct ch emical species. The structure of the system is globally non-linear and the coupling is taken into account by mass conservation, energy exchange, and r adiation-matter interaction. The radiative transfer also depends on atomic and molecular spectra in conditions of nonequilibrium for which cross secti ons and reaction rates are not well known and difficult to calculate.