Major mechanisms governing the mixing process of a gas injected into a long confined chamber is analyzed when there’s a relative motion between the two. Such applications arise in a wave rotor combustor where the moving combustion chambers receive gas from stationary injectors for fueling and ignition. Counter rotating vortices govern the mixing process in such problems, which moves across the channel enhancing mixing. The actions of vortices were seen to localize the injected gas in the vicinity of the injector end wall which can prove advantageous during fueling to make a rich mixture near the ignition source and during hot gas injection for ignition to minimize the drop of temperature. The vortex structures can alter the exit conditions of the injector due to its strong near field interactions. The confinement is also important in which it suppresses the development and motion of such vortices and hence affect mixing. Predictions using multi-dimensional numerical tools are presented in this book to analyze the mixture preparation, ignition potential and flame propagation in a wave rotor combustor fueled and ignited by translating jets.