Comprehensive Analysis, Prediction, and Validation of UH-60A Blade Loads in Unsteady Maneuvering Flight

摘要

This paper describes the prediction of rotor blade loads in unsteady maneuvering flight using lifting line comprehensive analysis. A multibody based finite element structural dynamics model is tightly coupled to an unsteady lifting line aerodynamic model. The aerodynamic model is a N_bbladed transient model which combines 2D airfoil property tables with a Weissinger-L near wake model, a time marching free wake model, and a semi-empirical dynamic stall model (Leishman-Beddoes). The aerodynamic and structural loads are predicted for UH-60A flight 11029, which is an unsteady pull-up maneuver, and the effect of rotor wake and dynamic stall on the maneuver load prediction is studied. The analysis is able to predict the correct trends for the pitching moments and peak-to-peak structural loads. The servo loads trends are also predicted. Three stall cycles are predicted for intermediate revolutions (11-14). It is concluded that this flight is a stall dominated, and not a wake dominated flight.