CFD Study of Coupled Flow due to Frigate Airwake and Helicopter Rotor Downwash on Flight Deck

This paper discusses the effect of modifying the hangar shape on the dynamic interaction of ship airwake and rotor downwash of the helicopter using computational fluid dynamics (CFD). A traditional 1:100 scaled simplified frigate ship (SFS-2) is modified to obtain trapezoidal and rectangular configurations of the hangar. The coupled interaction of ship airwake formed behind the ship subjected to free stream velocity of 6 m/s with the downwash generated by helicopter rotor hovering at 5000 rpm is simulated using STARCCM + CFD solver. The Reynolds-averaged Navier–Stokes equation is solved with conventional k-ω two-equation turbulence model to simulate the flow. The helicopter rotor thrust coefficient on hovering plane and landing plane is calculated for all the three SFS-2 configurations. The resultant velocity flow field of the ship airwake and rotor downwash is surveyed to compare the turbulence intensities at four equidistant lateral planes along the flight deck for a zero wind-over-deck (WOD) angle. The modified hangar configurations are shown to improve the coupled flow aft of the hangar.