A Prediction of Open and Closed Wake in Plug Nozzles

The capability of predicting the wake behavior during flight operations is necessary to design and fully exploit plug nozzle engines. This capability can be improved by a continuous growth of the knowledge of flow phenomena involved. In particular, analysis of CFD and experimental results are of great help to this goal. This paper presents a study of the plug nozzle wake and of the main flow features affecting its behavior. The study relies on the results of numerical simulations carried out by a validated RANS solver, based on the fitting of flow discontinuities. Differences between the flow features depending on the flight Mach number are emphasized and discussed, with the evidence of a possible deterioration of performance for increasing flight speed in the upper end of the open wake regime.