Experimental Flow Control on a Simplified Ship Helideck

The airwake of a simplified frigate shape is analyzed with an active flow control system embedded on the hangar sides, as part as a global study aiming at improving the complex flow topology encounter in helicopter launch and recovery operations. The flowfield above the helideck is experimentally analyzed using stereo particle image velocimetry, unsteady pressure sensors, and hot-wire anemometry. Results show a successful reduction of the recirculation region with continuous steady blowing around the hangar, observed at different yaw angles. It is shown that active flow control alters the airwake in a manner different from that passive devices. Locally, the turbulence levels are increased around the separated region boundaries when control is applied, whereas they are decreased in the wake downstream of the helideck. The frequency contents of the different airwake structures are not modified.