Prediction of the aerodynamic behaviour of a full-scale naval ship in head waves using Detached Eddy Simulation

The airwake behaviour around a ship provides useful information for the safe operation of helicopters on naval ships as well as in helicopter pilot training. This study investigates the impact of ship motions on the airwake behind the superstructure of a naval ship using Detached Eddy Simulation. A full-scale simplified frigate geometry is analysed stationary and in head waves at three different wavelengths under a uniform wind field and in the presence of an atmospheric boundary layer. The results reveal that an atmospheric boundary layer impacts significantly the airwake, as well as the vertical wave-induced motions of the ship, which reduce in amplitude by between 20.9% and 22.39% in heave, and up to approximately 38% in pitch. Moreover, the results show that the presence of an atmospheric boundary layer impacts the ship's heave and pitch motion periods. The flow field is also significantly altered depending on the ambient wavelength and period of motion, particularly in the case where an atmospheric boundary layer is modelled

The Development, Validation, and Integration of Aircraft Carrier Airwakes for Piloted Flight Simulation

This thesis reports on an investigation into the effects of ship airwake upon piloted aircraft operating to the United Kingdom’s newly commissioned Queen Elizabeth Class (QEC) aircraft carriers. Piloted flight simulation has been used to inform operation of aircraft to the ship, helping to identify potential wind-speeds/directions requiring high pilot workload prior to First of Class Flight Trials (FOCFT) aboard HMS Queen Elizabeth. The air flow over the QEC was generated using full-scale, time-accurate Computational Fluid Dynamics (CFD) at a range of wind azimuths, with the resultant airwakes incorporated into the flight simulators at both the University of Liverpool and BAE Systems Warton, enabling unsteady aerodynamic loads to be imposed upon rotary-wing and fixed-wing aircraft models, respectively. An additional CFD airwake was generated around a US Navy LHA helicopter carrier, and a comparison was made with real-world anemometer data in an attempt to validate the CFD method used for QEC. LHA at-sea measurements were found to be unreliable for CFD validation due to the inherent unpredictability of at-sea testing. As a result, an experimental validation experiment was recommended to validate the QEC CFD airwakes. A comparison was also made between LHA and QEC, with the twin-island QEC found to have increased turbulence gradient across the flight deck when compared with the single-island LHA. A description is given of the development of a novel Acoustic Doppler Velocimetry (ADV) experiment in a recirculating water channel, for which a 1:202 scale (1.4m) physical model of QEC was produced. To ensure spatial accuracy of ADV probe measurements 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. Finally, the validated CFD airwakes were incorporated into the HELIFLIGHT-R piloted flight simulator at Liverpool, for which a QEC simulation environment has been developed. Two former Royal Navy test pilots then performed a series of landings to the deck of the QEC in a Sikorsky SH-60 Seahawk, to demonstrate this newly developed capability at Liverpool, and to provide an initial assessment of pilot workload in varying wind speeds and azimuths, prior to real-world FOCFTs. The findings of this initial flight testing is reported in this thesis, as are conclusions and recommendations for future work

1995 BRAC Commission

ARD Detachment, Naval Surface Warfare Center Carderock Division, Naval Surface Warfare Center Carderock Division Detachment Annapolis, Naval Surface Warfare Center Carderock Philadelphia Detachment. Features and capabilities, special facilities and equipment. Box 181, L-113