Contouring optimal three-dimensional nozzles

The contouring of near-optimal three-dimensional nozzles with subsonic flow regions is considered with reference to certain examples. The contouring is carried out in accordance with the earlier-developed direct optimization technique using the approximation of the surfaces of the objects under consideration by the Bernstein-Bézier polynomials and tested against both the solution of the optimization problem for the supersonic region of an axisymmetric convergent-divergent nozzle and the problem of contouring the supersonic region of a nozzle from the dense multi-nozzle maximum-thrust nozzle cluster. The problems of contouring three-dimensional transonic nozzles of an infrared stealth engine and the three-dimensional nozzle of a high-velocity ramjet are considered. The transonic nozzle optimization is realized within the framework of the Reynolds equations. A modified technique for describing the geometry under consideration using the inhomogeneous Bernstein-Bézier surfaces is proposed to more completely describe the set of the possible shapes.