Title page for ETD etd-04202000-14540007


Type of Document Dissertation
Author Limache, Alejandro Cesar
Author's Email Address alimache@vt.edu
URN etd-04202000-14540007
Title Aerodynamic Modeling Using Computational Fluid Dynamics and Sensitivity Equations
Degree PhD
Department Aerospace and Ocean Engineering
Advisory Committee
Advisor Name Title
Cliff, Eugene M. Committee Chair
Anderson, Mark R. Committee Member
Grossman, Bernard M. Committee Member
Lutze, Frederick H. Jr. Committee Member
Rogers, Robert C. Committee Member
Keywords
  • stability derivatives
  • aerodynamic forces
  • sensitivity equation method
  • CFD
Date of Defense 2000-04-10
Availability unrestricted
Abstract
A mathematical model for the determination of the aerodynamic forces acting on an aircraft is presented. The mathematical model is based on the generalization of the idea of aerodynamically steady motions. One important use of these results is the determination of steady (time-invariant) aerodynamic forces and moments. Such aerodynamic forces can be determined using computer simulation by determining numerically the associated steady flows around the aircraft when it is moving along such generalized steady trajectories. The method required the extension of standard (inertial) CFD formulations to general non-inertial reference frames. Generalized Navier-Stokes and Euler equations have been derived. The formulation is valid for all ranges of Mach numbers including transonic flow. The method was implemented numerically for the planar case using the generalized Euler equations. The developed computer codes can be used to obtain numerical flow solutions for airfoils moving in general steady motions (i.e. circular motions). From these numerical solutions it is possible to determine the variation of the lift, drag and pitching moment with respect to the pitch rate at different Mach numbers and angles of attack. One of the advantages of the mathematical model developed here is that the aerodynamic forces become well-defined functions of the motion variables (including angular rates). In particular, the stability derivatives are associated with partial derivatives of these functions. These stability derivatives can be computed using finite differences or the sensitivity equation method.
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