Flap Edge Noise Reduction Fins

NASA’s Langley Research Center has developed aircraft flap tip modifications that reduce noise produced during approach and landing. The modifications are rigid open lattice (honeycomblike) and fin structures (closely packed columns) that delay the formation of a noise-generating vortex at the flap side edge. The designs are low-profile, with control action limited to the steady and fluctuating fields in a very small region at the flap edge. By limiting the control action to a very small region, aerodynamic characteristics of the structure remain nearly unchanged. The noise-reducing structures may be used in a variety of applications where tip vortices produce undesirable noise. These applications may include helicopter or wind turbine rotors. The technology has been validated using computational fluid dynamics analysis and wind tunnel testing. NASA is seeking partners who are interested in co-development or licensure of the technology for a variety of applications.