Transonic Shocks In Multidimensional Divergent Nozzles

We establish existence, uniqueness and stability of transonic shocks for steady compressible non-isentropic potential flow system in a multidimensional divergent nozzle with an arbitrary smooth cross-section, for a prescribed exit pressure. The proof is based on solving a free boundary problem for a system of partial differential equations consisting of an elliptic equation and a transport equation. In the process, we obtain unique solvability for a class of transport equations with velocity fields of weak regularity(non-Lipschitz), an infinite dimensional weak implicit mapping theorem which does not require continuous Frechet differentiability, and regularity theory for a class of elliptic partial differential equations with discontinuous oblique boundary conditions.Comment: 54 page

Design and analysis of an axisymmetric aerospike supersonic micro-nozzle for a refrigerant-based cold-gas propulsion system for small satellites

The cold-gas propulsion system being developed by M-SAT requires improvements to its original nozzle design. This study documents the research, design, and analysis of a supersonic plug nozzle concept that could be integrated to the refrigerant-based cold-gas propulsion system to possibly improve its performance. As documented in this thesis, CFD analysis showed that the outlined nozzle design method resulted in a feasible nozzle concept that has the ability to out-perform a conventional nozzle of the same area ratio. The flow-fields and thrust of the aerospike nozzle, for the full and truncated nozzles, were investigated. The purpose of this study is to investigate other rocket nozzles that might have the ability to improve performance of a propulsion system without a large penalty on vehicle mass or cost. Based on the information presented in this thesis, university-based satellite teams can manipulate the inputs of the design and analysis methods to investigate the use of an aerospike nozzle design concept to meet their design goals --Abstract, page iii

Aeronautical Engineering: A special bibliography with indexes, supplement 67, February 1976

This bibliography lists 341 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1976

A semi-quantitative schlieren high-speed flow diagnostic : analysis of high-pressure-ratio, overexpanded planar flow in rocket nozzles

This work introduces a semi-quantitative schlieren (SQS) method which is used to qualitatively and quantitatively analyze complex, unsteady, compressible flows in a small, planar convergent-divergent nozzle. A basic schlieren system is used to image the evolution in time of complex supersonic flow structures, including Prandtl-Meyer expansion fans, internal shocks, near-wall oblique shocks, quasi-normal shocks, shock/boundary layer interactions, shock/shock interactions, and shock trains. The first images of shock trains in high nozzle-pressure-ratio flows are shown, and the underlying processes are described. A flow-field decomposition method is presented which allows the entire flow field to be separated into unit processes and analyzed. Various methods of analysis are presented, including a new method for the determination of node locations along a defined nozzle wall geometry using the method of characteristics. A numerical solution is developed for the analysis of a blow-down process. Computer programs which implement these solutions are presented