Title page for ETD etd-11152007-125641


Type of Document Dissertation
Author De Oliveira Neto, Pedro Jose
Author's Email Address pneto@vt.edu
URN etd-11152007-125641
Title An Investigation of Unsteady Aerodynamic Multi-axis State-Space Formulations as a Tool for Wing Rock Representation
Degree PhD
Department Aerospace and Ocean Engineering
Advisory Committee
Advisor Name Title
Mason, William H. Committee Chair
Cliff, Eugene M. Committee Member
Durham, Wayne C. Committee Member
Hall, Christopher D. Committee Member
Woolsey, Craig A. Committee Member
Keywords
  • Wing Rock
  • Nonlinear Dynamics
  • Stability Derivatives
  • Unsteady Aerodynamics
  • High Angle of Attack
Date of Defense 2007-08-29
Availability unrestricted
Abstract
The objective of the present research is to investigate unsteady aerodynamic models with state equation representations that are valid up to the high angle of attack regime with the purpose of evaluating them as computationally affordable models that can be used in conjunction with the equations of motion to simulate wing rock. The unsteady aerodynamic models with state equation representations investigated are functional approaches to modeling aerodynamic phenomena, not directly derived from the physical principles of the problem. They are thought to have advantages with respect to the physical modeling methods mainly because of the lower computational cost involved in the calculations. The unsteady aerodynamic multi-axis models with state equation representations investigated in this report assume the decomposition of the airplane into lifting surfaces or panels that have their particular aerodynamic force coefficients modeled as dynamic state-space models. These coefficients are summed up to find the total aircraft force coefficients. The products of the panel force coefficients and their moment arms with reference to a given axis are summed up to find the global aircraft moment coefficients. Two proposed variations of the state space representation of the basic unsteady aerodynamic model are identified using experimental aerodynamic data available in the open literature for slender delta wings, and tested in order to investigate their ability to represent the wing rock phenomenon. The identifications for the second proposed formulation are found to match the experimental data well. The simulations revealed that even though it was constructed with scarce data, the model presented the expected qualitative behavior and that the concept is able to simulate wing rock.
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