A Chapman-Korst-type analysis has been developed for estimating the bulk base flow properties of nozzle-afterbody configurations operating at supersonic speeds. The analysis includes the effects of both initial boundary layers, dissimilar thermodynamic properties of both streams, and a third base bleed gas. The inviscid portions of the jet and external flow are computed by the method of characteristics. The turbulent mixing analysis uses the turbulent kinetic energy method to determine the coefficient in a Prandtl-type eddy viscosity model. The empirical coefficients in the turbulent kinetic energy formulation are those developed for the turbulent mixing of jet flows. A new analytical model of the recompression process has been developed that eliminates the need for an empirical recompression factor to determine the stagnating streamline. The analysis is evaluated by comparing with experimental data for Mach 2.0 flow over a two-dimensional blunt base with hydrogen bleed, a two-dimensional backward-facing step and a hot and a cold rocket nozzle-afterbody configuration. Usually the theoretical base pressure is greater than experimental base pressure, indicating the mixing rate is too small. However, the recompression analysis predicts reasonable values of the recompression factor. (Author).