Numerical Studies of Active Flow Control Applied at the Engine-Wing Junction

This paper presents a numerical study of active flow control applied at the engine-wing junction to increase the high-lift performance of a generic full scale wind tunnel model representing a landing configuration of conventional airliners with engines mounted under backward swept wings. The use of UHBR (Ultra High Bypass Ratio) engines is currently one of the most promising approaches to further increase the efficiency of transport aircraft. However their large engine diameter prevents the mounting of leading edge devices at the engine-wing junction. This leads to a local flow separation on the wing suction side in the wake of the nacelle which may trigger the total wing stall and hence compromises the high-lift performance and therefore the total aircraft efficiency. At DLR (German Aerospace Center) numerical simulations of AFC (active flow control) at the engine-wing junction were conducted to study the capability of suppressing this local flow separation. The effects of steady and pulsed jet blowing with the same actuator geometry are compared. The results show that the steady blowing reduces the size of the nacelle-wake separation. However the pulsed blowing of the analyzed setup shows a low effect on the size of the nacelle-wake separation.

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