Experimental Comparison of Flow Control techniques on Helicopter flight deck of Frigates

Abstract

Helicopter operations on frigates provide important support for navies. However, the non-aerodynamics shapes of a frigate generates complex airflow characterized by low-speed regions, flow detachments and high turbulence intensities. This makes an increase in the helicopter pilot workload that can lead to dangerous situations. Flow control can be used for reducing the flow detachment above the flight deck of a frigate and minimize the risk of such operations. In this paper, a comparison of different flow control methods applied to a Simple Frigate Shape 2 are performed. On one hand, passive flow control by means of vortex generators and hangar shapes modifications are analyzed. On the other hand, active flow control using plasma actuators, blowing and suction from the hangar and flight deck, and Coanda Effect are presented. All methods are compared using velocity contours obtained with Particle Image Velocimetry (PIV) in wind tunnel. The results show that geometrical modifications of the hangar and active flow control using blowing or suction can reduce drastically the flow detachment and the recirculation bubble on the flight deck.