AERODYNAMIC DESIGN FOR SUPERSONIC NOZZLES OF ARBITRARY CROSS-SECTION

A comparatively simple method for obtaining wall contours of supersonic nozzles of arbitrary exit cross sections from readily determined axisymmetric flows is presented. An initial axisymmetric flowfield is calculated using the method of characteristics in two dimensions from which the desired three-dimensional shape may be generated by specifying the appropriate cross section at the streamwise station giving the required overall nozzle length and exit Mach number. The describing points on the perimeter of this section are traced along corresponding streamlines back to the throat. The stream sheets formed by these streamlines then define the new nozzle contour. Elliptical and two-dimensional wedge-shaped nozzles are designed using this approach, and comparisons are reported between detailed finite-difference flowfield predictions and experimental measurement.