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Title: The Queen Elizabeth Class Aircraft Carrier: Airwake Simulation and Validation for ASTOVL Operations

Author(s): M F Kelly, M D White, S Hodge, I Owen

Abstract: This paper will outline current progress towards development of a high-fidelity piloted flight simulation environment for the UK’s Queen Elizabeth Class (QEC) aircraft carriers that are currently under construction. Piloted flight simulation will be used to inform operation of Advanced Shipborne Take-Off/Vertical Landing (ASTOVL) aircraft to the ship, helping to identify potential wind-speeds/directions requiring high pilot workload prior to First of Class Flight Trials (FOCFT). By identification of areas of highest pilot workload using flight simulation, test pilots will be able to concentrate their efforts on these conditions during full-scale testing, minimising both required flight hours and time spent at sea dedicated to FOCFT. The air flow over and around the QEC has been generated using Computational Fluid Dynamics (CFD). The resultant air-wake will be incorporated into the flight simulators at the University of Liverpool and BAE Systems Warton, enabling unsteady aerodynamic loads to be imposed upon the aircraft. Owing to the necessity for fixed wing aircraft to traverse through the highly turbulent, massively separated “burble” region immediately aft of the aircraft carrier during a Shipborne Rolling Vertical Landing (SRVL) attempt, particular attention is given to accurate reproduction of the air-wake in this region, presenting unique challenges in terms of both solution accuracy and data look-up/storage during piloted flight simulation exercises. Vertical Take-Off and Landing (VTOL) imposes additional requirements upon a QEC CFD solution, further increasing the air-wake grid-density. The University of Liverpool has considerable experience of simulating helicopter operations to frigate and destroyer sized Royal Navy (RN) ships, however the fixed-wing requirement for an accurate reproduction of the carrier burble region up to 0.25mi aft of the ship necessitates experimental validation of CFD data to ensure solution accuracy. QEC air-wake validation efforts are outlined, in particular development of an Acoustic Doppler Velocimetry (ADV) experiment in the University’s 80,000 litre recirculating water channel, for which a 1:202 scale (1.4m) physical model of QEC has been produced. To ensure spatial accuracy of ADV measurement during validation, an electronic, programmable three degree-of-freedom traverse system has also been incorporated into the water channel, allowing automated positioning of the ADV probes along the SRVL glideslope with sub-millimetre accuracy. The development of this experiment is outlined, while comparisons will be performed with CFD results.