Title page for ETD etd-01272004-110610


Type of Document Master's Thesis
Author Heim, Eugene Henry DeWendt
Author's Email Address eheim@vt.edu
URN etd-01272004-110610
Title Development of Methods for Improved Data Integrity and Efficient Testing of Wind Tunnel Models for Dynamic Test Conditions in Unsteady and Nonlinear Flight Regimes
Degree Master of Science
Department Aerospace and Ocean Engineering
Advisory Committee
Advisor Name Title
Mason, William H. Committee Chair
Brandon, Jay M. Committee Member
Woolsey, Craig A. Committee Member
Keywords
  • Static
  • Forced Oscillation
  • Data Integrity
  • Efficient Testing
  • Wind Tunnel Testing
  • Uncertainty
Date of Defense 2003-12-18
Availability unrestricted
Abstract
Today’s high performance aircraft are operating in expanded flight envelopes, often maneuvering at high angular rates at high angles-of-attack, even above maximum lift. Current aerodynamic models are inadequate in predicting flight characteristics in the expanded envelope, such as rapid aircraft departures and other unusual motions. Unsteady flows of aircraft are of real concern. The ability to accurately measure aerodynamic loads directly impacts the ability to accurately model and predict flight. Current wind tunnel testing techniques do not adequately address the data fidelity of a test point under the influence of fluctuating loads and moments. Additionally, forced oscillation test techniques, one of the primary tools used to develop dynamic models, do not currently provide estimates of the uncertainty of the results during an oscillation cycle. Further, in testing models across a range of flight conditions, there are frequently parts of the envelope which are well behaved and require few data points to arrive at a sound answer, and other parts of the envelope where the responses are much more active and require a large sample of data to arrive at an answer with statistical significance. Currently, test methods do not factor changes of flow physics into data acquisition schemes, so in many cases data are obtained over more iterations than required, or insufficient data may be obtained to determine a valid estimate. Methods of providing a measure of data integrity for static and forced oscillation test techniques are presented with examples. A method for optimizing required forced oscillation cycles based on decay of uncertainty gradients and balance tolerances is also presented.
Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  FO_pitch.JPG 103.89 Kb 00:00:28 00:00:14 00:00:12 00:00:06 < 00:00:01
  FO_roll.JPG 100.71 Kb 00:00:27 00:00:14 00:00:12 00:00:06 < 00:00:01
  FO_yaw.JPG 86.56 Kb 00:00:24 00:00:12 00:00:10 00:00:05 < 00:00:01
  Pitch_Oscillation.avi 2.10 Mb 00:09:43 00:05:00 00:04:22 00:02:11 00:00:11
  Roll_Oscillation.avi 3.22 Mb 00:14:54 00:07:40 00:06:42 00:03:21 00:00:17
  Thesis_v326.pdf 4.29 Mb 00:19:51 00:10:12 00:08:56 00:04:28 00:00:22
  Yaw_Oscillation.avi 2.95 Mb 00:13:40 00:07:02 00:06:09 00:03:04 00:00:15

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