Low order supersonic nozzle design using superimposed characteristics

This paper presents a new technique in the development of non-axisymmetric 3D nozzle geometries via application of the 2D method of characteristics. A novel superimposed characteristics technique is presented herein, which provides a low order scheme for preliminary nozzle design. This design method is illustrated by application to a scarfed nozzle with non-uniform exit flow. However, the general technique may be expanded and applied to a range of nozzle geometries and other applications. In this investigation a desired exhaust velocity profile for a scarfed nozzle exit is initially defined and the superimposed characteristics technique is then applied to generate a nozzle geometry. This nozzle and therefore the approach are assessed using experimental methods and commercial CFD analysis. The results of the investigation show that a high level of agreement between the predicted and experimental data can be attained using the design technique presented. Furthermore, it was found that improved design accuracy can be achieved by the inclusion of viscous effects and the application of the resulting boundary layer corrections. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.