A Comparative Assessment of the NATO-GD and SFS2 Ship Airwakes and their Influence upon Helicopter Aerodynamic Loading

The purpose of this study was to assess and compare the airwakes of two generic ship models, the NATO-GD and the SFS2, and their impact upon helicopter aerodynamic loading in operations over a ship's deck. Airwakes were computed using Delayed Detached Eddy Simulation, a time accurate CFD approach, for each ship model in a headwind and a Green 30 wind. The CFD airwakes were then integrated with a helicopter flight dynamics model, representative of an SH-60B Seahawk. The helicopter model was held stationary at a number of points along a lateral traverse profile over the flight deck of each ship, and the unsteady aerodynamic loads on the fixed-position helicopter were recorded and compared for the two ships. It was seen that the NATO-GD airwake created higher levels of turbulence and greater unsteady loads on the helicopter model than did the SFS2 airwake, implying greater workload for a pilot.