Optimally Actuated Spanwise-Segmented Aerodynamic Effectors for Rotorcraft Power Reduction

摘要

This paper examines the use of optimally actuated, spanwise-segmented aerodynamic effectors for rotorcraft power reduction. Four effectors, extending from 50-60%, 60-70%, 70-80% and 80-90% span, were considered and actuated at frequencies of 1/rev and 2/rev. A gradient-based optimization scheme was used to determine the actuation schedule that minimized rotor torque, while satisfying vehicle trim. Simulations were based on a UH-60A type aircraft with CFD-based increments (deltas) in aerodynamic coefficients due to the effectors added to the base SC-1094R8 airfoil characteristics. At high gross-weights, and/or very high speed, reductions in rotor power ranging from 5.7- 6.6% were predicted (depending on the specific effector used). The effectors were primarily deployed on the retreating side of the disk, moved lift inboard, and unloaded the outer rim of the rotor disk along with a corresponding large reduction in outer rim drag. The increased lift generated by the effectors reduced rotor collective and longitudinal cyclic pitch and reduced angles of attack around the disk, especially on the retreating side. Reduced power requirement came primarily from profile power reduction associated with a more optimal airload distribution enabled by the effectors.