Detonation has received attention of late because of its role as the primary combustion mechanism in rocket and airbreathing Pulse Detonation Engines (PDEs). However, there are many unresolved issues related to the proper utilization of detonation combustion in these applications. The detonation process has been studied predominantly under the assumption of premixed gases. However, the unsteady nature of PDEs requires relatively small tunes to inject and mix the propellants prior to each cyclic detonation; and this condition is difficult to achieve experimentally. This paper addresses the injection and mixing processes, and presents new data aimed at supporting the development of practical PDEs. Results are given to illustrate the mixing characteristics of fuel-oxidizer mixtures, modeled with a CFD combustion code.