Delaying the Stall: LERX Flow ControlJaden WenigerAward: Top 100
School: saint john's preparatory school This 3d printed Sukhoi SU-27 Fighter jet generates a lift-providing vortex with Leading Edge Root Extensions (LERX). When a fighter jet maneuvers, it loses energy. As it slows down, the wing must move at a higher angle relative to the direction it's moving through the air. This angle is called the angle of attack (AoA), and is very important in aerodynamic engineering. This, however, creates an issue. Air is not "required" to flow smoothly over the wing. The higher the AoA, the sooner critical flow over the wings separates. Designing a fighter jet that is both fast and maneuverable encounters that issue specifically. The solution to this was leading edge root extensions. I put the model in my specialized wind tunnel, and as demonstrated, the root extension at the base of the wing is generating a Vortex; a spinning column of air. The LERX vortex acts as a flow-control device, mechanically delaying flow separation by 'pinning' the air to the wing's upper surface, generating a low pressure zone and in turn, lift. You can also identify its efficiency by analyzing the turbulent flow behind the aircraft, where almost all air in the system has been directed downwards into coherent flow rather than chaotic, high-drag turbulence, making for efficient maneuvering. 
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