Papers Published

1. Thomas, J.P. and Dowell, E.H. and Hall, K.C., Nonlinear inviscid aerodynamic effects on transonic divergence, flutter and limit cycle oscillations, Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, vol. 1 (2001), pp. 230 - 241 .
   (last updated on 2007/04/10)

   Abstract:
   Using a state of the art computational fluid dynamic (CFD) method to model nonlinear steady and unsteady transonic flows in conjunction with a linear structural model, an investigation is made into how nonlinear aerodynamics can effect the divergence, flutter, and limit cycle oscillation (LCO) characteristics of a transonic airfoil configuration. A single degree of freedom (DOF) model is studied for divergence, and one and two DOF models are studied for flutter and LCO. A harmonic balance method in conjunction with the CFD solver is used to determine the aerodynamics for finite amplitude unsteady excitations of a prescribed frequency. A procedure for determining the LCO solution is also presented. For the configuration investigated, nonlinear aerodynamic effects are found to produce a favorable transonic divergence trend, and unstable and stable LCO solutions respectively for the one and two DOF flutter models.

   Keywords:
   Aerodynamics;Transonic flow;Flutter (aerodynamics);Oscillations;Computational fluid dynamics;Mathematical models;Degrees of freedom (mechanics);