Analysis of Power Losses and Wake Entropy Production for Hypersonic Flight Vehicles


We examine the governing relationships between forces experienced by a vehicle, vehicle power usage, losses and entropy production. Vehicle wake losses (like losses associated with the vehicle itself) are shown to be directly related to lost force power increments on the vehicle. Conventional exergy (or availability) methodology without explicit consideration of the wake and, specifically, without consideration of vehicle flow-field/wake entropy relationships, is shown to be problematic for accurate assessment of losses. The methodology is then re-formulated with explicit consideration of the vehicle/wake entropy relationship. Lost power increments are derived, hence allowing the detailed analysis/auditing of vehicle performance. This methodology is rigorously related throughout its entire development to the concept of wake entropy production and the important impact of vehicle entropy production and characteristics on the wake entropy production. The fundamental thermodynamic linkages and relationships between force, entropy, and power for an individual streamtube are examined. These analytical results are then expanded to entire flow-fields characteristic of vehicles in flight (multiple streamtubes in and over vehicle surfaces and downstream wake equilibration of those streamtubes) in order to unify explicit force-based methodology and the entropy method. The ongoing research represented by this and previous work should ultimately enable the integration of all vehicle subsystems (not just aerodynamic and propulsive subsystems) using a synergistic currency for analysis, design, and, ultimately, optimization of aerospace vehicles.

Meeting Name

14th AIAA/AHI Space Planes and Hypersonic Systems and Technologies Conference (2006: Nov. 6-9, Canberra, Australia)


Mechanical and Aerospace Engineering

Keywords and Phrases

Power Usage; Vehicle; Vehicle Wake Losses

Document Type

Article - Conference proceedings

Document Version


File Type





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

Publication Date

09 Nov 2006

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