Comparison of Transonic Flow Solutions in C-D Nozzles

The method of characteristics has proven to be a highly accurate and relatively straight forward technique for computing the supersonic flow field in a two-dimensional or axisymmetric nozzle. However, the method of characteristics requires an initial value line traversing the flow in the fully supersonic region on which the flow properties are known. A parametric study of the effect of different transonic flow calculation methods for establishing the initial value line for axisymmetric converging-diverging nozzles was conducted. The Mach number and radial velocity distributions along a reference start line were calculated and compared for several different transonic solutions for a series of nozzles with different throat radii of curvature. These initial value lines were then used to initiate a method of characteristics analysis of several geometrically different axisymmetric nozzles in order to investigate the impact on calculated performance.