Title

Incorporation of computational fluid dynamics into flight vehicle preliminary design

Date of Award

2012

Degree Name

Ph.D. in Aerospace Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Advisor: Franklin E. Eastep

Abstract

Nonlinear, high fidelity aerodynamic analysis methods are considered computationally expensive and impractical for use in the preliminary design environment. In lieu of nonlinear methods, linear aerodynamic methods are utilized in the execution of design tasks because of their computational efficiency. Linear codes are considered accurate in low Mach number flight regimes where aerodynamics is generally linear but are not accurate in transonic flight regime due to the simplified assumptions that are required by such codes. This investigation demonstrates that nonlinear aerodynamic analysis methods are necessary when performing design tasks in the presence of nonlinear phenomena. To reduce the cost of using nonlinear aerodynamic analysis, the velocity transpiration boundary condition was employed to simulate surface deformations and control surface deflections. Observations showed velocity transpiration offers significant computational savings when compared to mesh motion enabled codes. To improve turnaround, a distributed computing framework was adopted to distribute workload and information storage across a network. A comparative design study was carried out comparing linear and nonlinear analysis tools in design. A rectangular wing's structural mass was optimized to perform both a roll and pull-up maneuver while subjected to roll effectiveness and skin stress constraints. At a subsonic design point, the linear and nonlinear tools produced similar designs. However, at a transonic design point, the tools produced significantly different designs. The addition of aerodynamic shape variables to the design space at the transonic design point led to a further enhanced design. The results of this study reaffirm the notion that nonlinear high-fidelity aerodynamic analysis methods must be utilized when designing vehicles that will operate in nonlinear regimes. Further, several methods were demonstrated that could reduce the cost of using nonlinear analysis methods.

Keywords

Aerodynamics, Transonic Methodology, Jet planes Design and construction

Rights Statement

Copyright © 2012, author

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