The Second-Law based Analysis of Aerospace Vehicle Performance


The work presented here is part of research to develop a methodology for complete system-level integration of flight vehicles. Specifically, this work focuses on the development of a common currency for loss assessment for the aerodynamics and propulsion sub-systems of an aerospace vehicle with particular focus on high-speed flight. Theory, methodology, and example applications are developed and shown for the systematic analysis of overall vehicle forces in terms of irreversibility and heat. The methodology presented involves analyzing and deconstructing vehicle forces using individual stream tubes as components within the overall fluid control volume in which the vehicle is embedded. This provides the capability for the complete fluid/thermo-dynamic 'audit' of vehicle performance in terms of irreversibility, combustion (heating), and fluid dynamic flow turning and area change. Sample results are shown for a simplified hypersonic vehicle configuration modeled with constant specific heats and Raleigh heating. The role of overall entropy generation and wake mixing processes in the production of vehicle forces in atmospheric flight is next discussed and clarified. Specifically, the direct analytical relationship between entropy, wake mixing processes, and overall force production for the vehicle is developed from fundamental considerations of the global control volume with inclusion of the wake in the analysis. This analysis is demonstrated using the same simplified high-speed configuration and is finally developed for the completely general problem of an aerospace vehicle with variable specific heats, thermal loading, variable composition, fuel injection, and chemical reaction.

Meeting Name

44th AIAA Aerospace Sciences Meeting and Exhibit (2006: Jan. 9-12, Reno, NV)


Mechanical and Aerospace Engineering

Keywords and Phrases

Aerospace Vehicle; Flight Vehicles; System-Level Integration

Document Type

Article - Conference proceedings

Document Version


File Type





© 2006 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Publication Date

12 Jan 2006

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