Available Technology

Biologically Inspired Wing Flow Control

Flaps can significantly alter wing aerodynamics for high lift generation. Conventional flaps are mainly deployed for takeoff and landing but are not suitable for in cruise flight. It is widely speculated that birds and insects utilize their wing flexibility particularly at the trailing edges for...
Abstract: 
Applied to a typical aluminum airfoil on a fixed wing aircraft, the technology involves adding a flexible strip which can adjust itself to the air flow to obtain drag reduction. Alternatively, sensors and actuators can be used for feedback control to make adjustments to the strip to optimize drag reduction. Depending on specific applications, the strip could be of an aluminum plate, polymer membrane, composite sheet or smart material plate. The effects of SETE on the wing aerodynamics are mainly due to modifications of the airfoil camber and of the flow structure at the trailing edge. The resulting improvement in aerodynamic efficiency leads to greater fuel efficiency and vibration control. For small aircraft like unmanned aerial vehicles (UAVs), the device can prevent flow separation, which can lead to stalling. The cover photo shows the asymmetry of the flow field induced by SETE where wake is turned downward, indicating a deflected momentum stream tube and generation of additional lift. The wake structure is not appreciably altered indicating that the parasite drag is not significantly affected. Figure 2 is a CFD simulation at 6 degree deflection.
Benefits: 
Improves fuel efficiency -Allows greater suppression control -Can prevent stalling from flow separation -Existing airframes can be easily modified to use technology -Technology can be mounted on trailing edge or in other locations
applications: 
Agency
NASA
State: 
Virginia
Lab Representatives
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