Application of a New Compressible Time Domain Aerodynamic Model to Vibration Reduction in Helicopters Using an Actively Controlled Flap

摘要

This paper describes an aeroelastic simulation of a fully elastic hingeless helicopter rotor incorporating a partial span trailing edge flap. Aerodynamic loads are provided by a new, two-dimensional, compressible flow unsteady aerodynamic model developed for an airfoil/flap combination and unsteady freestream. Aerodynamic loads are approximated in the frequency domain as rational functions of the Laplace variable using a least squares fit to oscillatory response data. Transformation to the time domain yields a state space model for the unsteady aerodynamic loads. Frequency domain loads are obtained using a two dimensional doublet-lattice analysis. Vibration control studies using the actively controlled flap are presented, with comparisons to results obtained using quasisteady aerodynamics.