Date of Award

3-22-2012

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Andrew J. Lofthouse, PhD.

Abstract

Difficulties in obtaining accurate Stability and Control (S&C) data for nonlinear regions in the flight envelope early in the design phase often lead to costly fixes late in the acquisition process. Work examined herein addresses this problem by utilizing recent advances in Computational Fluid Dynamics (CFD) to create a high-fidelity database before any parts have to be physically produced. In combination with CFD, System Identification (SID) is used to characterize the S&C characteristics of aircraft by some Reduced Order Model (ROM). The method of obtaining enough data in the right places, via some optimized maneuver, to create an accurate ROM is the main focus of this work. A series of metrics was created and validated to help identify the quality of any maneuver before it is even run. To validate the metrics, seven different maneuvers were generated, run, and used to create models. These models are then evaluated against sets of results from validation maneuvers to show the accuracy of modeling a given regressor space -- the regressor space being the required variations of the model variables (angle of attack, pitch rate, etc.). From the validated metrics, the best maneuver for creating the most accurate model of a given grid within a specified regressor space is defined.

AFIT Designator

AFIT-GAE-ENY-12-M04

DTIC Accession Number

ADA558277

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