Issued patent
Low, Drag, Variable-Depth Acoustic Liner
An issued NASA patent from the Technology Transfer catalog.
About this technology
Overview
A low-drag, variable-depth acoustic liner has been designed for aircraft noise reduction. The technology can be used as a conventional engine nacelle liner, or on the external surfaces of an aircraft to reduce acoustic scattering. As compared with conventional liners, the technology provides increased broadband acoustic performance with less drag. Conventional liners use a perforated facesheet as the outermost portion of the liner exposed to flow. The perforated facesheet has a higher drag than a smooth surface, but is necessary to reduce noise. The proposed innovation reduces the open area of the facesheet, and therefore reducing the drag of the liner, without compromising acoustic performance.