Abstract: The high enthalpy gas flows, associating high velocities, and high temperatures, are the scene of physical and chemical processes such as molecular vibrational excitation, dissociation, ionization, or various reactions. The characteristic times of these processes are of the same order of magnitude as aerodynamic characteristic times so that these reactive media are generally in thermodynamic and chemical non-equilibrium. This book presents a general introductory study of these media. In a first part their fundamental statistical aspects are described, starting from their discrete structure and taking into account the interactions between elementary particles: the transport phenomena, relaxation, and kinetics as well as their coupling are thus analysed and illustrated by many examples. The second part of the work is devoted to the macroscopic aspects of the reactive flows including shock waves, hypersonic expansions, flows around bodies, and boundary layers. Experimental data on vibrational relaxation times, vibrational populations, and kinetic rate constants are also presented. Finally, experimental aspects of reactive flows, their simulation in shock tube and shock tunnel are described as well as their applications, particularly in the aero-spatial domain.

Keywords: statistical description, non-equilibrium flow, high speed flow, transport processes, vibrational relaxation, chemical kinetics, shock tube, aerospace