Unsteady Loads of a Scaled Rotor on and Near the Landing Deck of the NATO Generic Destroyer with Concurrent Stereo PIV and Surface Pressure Measurements

Abstract

Rotorcraft shipboard operations are risky and demand high piloting skills. To gain further understanding and familiarize pilots with these complicated scenarios, various methods of computational simulations have been used in the past decades. Yet, some simulation methods may not capture a realistic response of the rotorcraft due to simplified modeling of the interactional aerodynamics in order to achieve real-time capability for pilot training. Thus, improvements to these simulations are required, and experimental data that unveil the interactional aerodynamics and dynamics between the rotor and ship are needed for computational validation efforts. In this study, an extensive experimental investigation of the ship–rotor dynamic interface problem was conducted to gain a general understanding of the interactional aerodynamics between a 1:100 wind-tunnel-scale NATO Generic Destroyer and a representative single main rotor, operating both stationary and dynamically moving in space in the vicinity of the landing deck. Data obtained through simultaneous measurements of rotor hub loads, ship deck surface pressures, and stereoscopic particle image velocimetry flow fields gave valuable insight into the highly coupled aerodynamic phenomena. Results showed that the rotor hub loads exhibited a high dependency on both the wind direction and also the position of the rotor relative to the landing deck. A bifurcation in the regions of high unsteady thrust was observed under certain wind conditions due to the ship airwake, impacting different portions of the rotor disk. The inflow angles across the rotor disk were estimated and assessed through flow field measurement, revealing how the ship airwake altered the rotor inflow and wake structure that contributed to the unique change in rotor loads under various hovering conditions.