Plug Nozzles: Summary of Flow

This paper represents an overview of the activities carried out in the framework of RTO/AVT Working Group 10, Subgroup 1, dedicated to plug nozzle aerothermodynamics and performance. The subgroup worked out two main objectives: i) thorough understanding of the flow physics of plug nozzles trough literature review and recent experiments conducted in Europe and USA; ii) definition of CFD test cases, conduction of CFD calculations and comparison with experimental data. This paper summarizes the findings of the flow physics based on literature review and recent experiments. It is the result of the many interesting discussions promoted by all members participating to the subgroup, whose contribution is acknowledged by the authors. In particular, the following key topics are discussed in depth in the paper: Survey on Past AGARD Activities. The Fundamental Aspects of Plug Nozzle Flowfields. The Wake Structure Transition from Open to Closed. The Influence of the External Flow. Plug Nozzle Base Pressure versus Flight Altitude. Altitude Adaptive Character of Plug Nozzles with Regard to Performance. Contour Design Methods. Aerospike: Thrust Vector Control.