| Ship airwakes is the main flow environment for shipboard-helicopters landing and take-off process, having an important influence on the ship-helicopter dynamic interface, which is one of the major causes of safety accident. In this paper, a wind tunnel experiment and CFD simulations of the SFS2 simplified frigate ship airwakes have been performed respectively. Wind tunnel tests adopt PIV method to obtain a two-dimensional flow field on spatial cross sections, and CFD simulations select the FLUENT solver, the RNG k-? turbulence model to calculate steady three-dimensional flow fields under the condition of scaled in wind tunnel and full size at sea, the flow field results have been studied in detail at several wind –over-deck(WOD) angles. Then, “SH-60B” model is established based on the FLIGHTLAB flight simulation system and import the steady flow field data of full-size CFD simulation into SFS2 ship model. Assume that the helicopter is keeping station on the flight deck landing point, a preliminary computation of the ship-helicopter launch and recovery flight limitations has been completed.SFS2 ship airwakes shows a typical characteristics of the flow around a bluff-body, that is, flow separation on the edge of the hangar and deck could result in a backflow zone, in which air velocity changes drastically, leading to deck flow disorder. At small WOD, flow field of the station-keeping zone is hardly affected by the recirculation region, air longitudinal velocity is given priority and lateral velocity and downwash velocity proportion is small, the helicopter hover trimming can overcome larger wind speed.With WOD increasing, air horizontal velocity component grows up, airflow environment in deck landing point area affected by the deck edge becomes poor, the wind speed limit for the helicopter hovering decreases, and port side wind is more suitable for helicopter landing than starboard side wind on account of roll attitude and tail rotor pitch control margin at hover. |
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