Effect of modifications to island shape and geometrical configuration on the external aerodynamics of a generic aircraft carrier

Abstract

The external aerodynamics of an aircraft carrier plays a vital role in the safe landing of aircraft during take-off and recovery. The hull, flight deck, and the island create a turbulent disturbance behind the aircraft carrier, leading to a simultaneous reduction in forward velocity and a downwash, which together create a sinking effect on the aircraft along its glideslope path. This phenomenon is known as the burble effect. It could potentially increase the pilot’s workload and strain their mental and physical faculties. Any design change that obviates or reduces the burble effect would potentially increase the probability of safely landing the aircraft on an aircraft carrier. There are only a few studies on the external aerodynamics of an aircraft carrier. The primary motivation of this study is to evaluate the effect of modifications to the island structure on the external aerodynamics of a generic aircraft carrier, especially the burble behind the carrier. The first part of the study pertains to the parametric changes to the aspect ratio of the island, that is, its length to width ratio and the consequent impact on the aerodynamics behind the carrier along the flight glide path. The second part of the study focuses on changing the geometry of the island by rounding the assumed cuboid island’s sharp corners, and evaluating its effect on the burble along the glideslope path of the aircraft. For the study, computational fluid dynamics (CFD) analysis on a generic aircraft carrier model has been carried out using the commercially available CFD solver Ansys FLUENT. The CFD studies have been validated by results of experiments conducted in a wind tunnel on the same generic aircraft carrier model. From the studies, it is seen that the aspect ratio of the island greater than one and rounding the sharp edges of the island have beneficial effects in reducing the impact of the burble behind the carrier.