Contour Generation
Precision Geometry from Throat to Exit
Technical Methodology
NozzlePy provides three primary contour generation programs for the design of axisymmetric, supersonic rocket nozzles: The Ideal Nozzle, the Truncated Ideal Contour (TIC), and the Thrust Optimized Parabola (TOP).
Ideal Nozzle
The Ideal Nozzle module computes a fully expanded, shock-free nozzle contour using the Method of Characteristics (MoC) for a user-defined exit Mach number. A complete characteristic mesh is generated, ensuring uniform flow properties at the nozzle exit. This contour represents the theoretical optimum in terms of expansion efficiency, but typically results in a relatively long nozzle geometry.
Truncated Ideal Contour (TIC)
The Truncated Ideal Contour is derived directly from the MoC-based ideal nozzle. The full contour is truncated at a user-defined axial location in order to reduce nozzle length and structural mass while maintaining a high thrust coefficient. Optionally, a geometric envelope can be applied to constrain the nozzle shape.
Thrust Optimized Parabola (TOP)
The Thrust Optimized Parabola implements the method established by G. V. R. Rao. In this approach, the divergent section of the nozzle is approximated by a parabola that is optimized to maximize thrust within a limited axial length. Compared to the ideal contour, the TOP nozzle achieves a higher thrust, at the cost of a non-uniform exit flow and the formation of an internal shock structure. This method is widely used in practical rocket engine designs.
Every Contour can be exported as a .DXF file - optimal for direct implementation into a CAD software.