Control of Wing-Engine-Slat Cut Out Flow Separation Using Nacelle Nozzle Modification

A numerical study on active flow control (AFC) to a swept wing in a take-off configuration was conducted. The focus of this study is the feasibility of the innovative active flow control (AFC) method by using the engine jet, and the control of the jet was achieved through the modification of the nacelle nozzle geometry. The modification included a partial cut or extension at the trailing edge of the nacelle. This AFC method is designed mainly for the flow control of wing-engine-slat cut-out position and it is an alternative design to the outboard nacelle strake. The target configuration integrated with this AFC design was a typical twin-engine jetliner with close-coupled High Bypass Ratio (HBR) engine nacelles. The basic take-off configuration was integrated with regular powered nacelles. Two modified configurations with different engine nozzle designs were also investigated and compared. The surface flow visualization and the spatial particle traces illustrated how the different nozzles affected the engine exhaust flow and the further impact on the aerodynamic performance of the wing. The simulation results showed this innovative AFC device can mitigate the aerodynamic performance degradation caused by the installation of large-diameter nacelles, and suppress the flow separation near the wing-engine-slat cut-out position. Meanwhile, the AFC method did not require additional mechanical mechanisms or any special maintenance, nor had any weight penalty. Therefore, this type of AFC device shows a high application potential in commercial transport aircraft.