Air curtains for landing gear noise reduction

This paper examines the implementation of air curtain nozzles to reduce the aerodynamic noise radiated from a modified scaled LAGOON landing gear and a detailed trailing-arm Main Landing Gear representing a generic Bizjet wing mounted gear provided by Dassault Aviation and Safran Landing Systems. At approach to landing, landing gear noise is still a significant contributor to environmental noise in the vicinity of airports. Progress is being made with ambitious projects which aim to develop significantly reconfigured aircraft architectures to reduce airframe noise. The current project examines a noise abatement concept which could be retrofitted to existing landing gear configurations as an interim measure or as part of a longer term solution. Flow control in the form of “air curtain” nozzles which create a fluidic shield or virtual fairing are examined. The air curtain concept was examined as a low test-readiness-level (TRL), high-risk, high-gain technology tested in the EU funded H2020 collaborative research project: INVENTOR, InnoVative dEsign of iNstalled airframe componenTs for aircraft nOise Reduction. The nozzles operate at high pressure with rows of choked-flow sub-millimeter holes. Narrow and broadband noise attenuation was achieved, with reductions of over 7 dB measured. The air curtains were examined in DLR's AWB aeroacoustic facility in Braunschweig, Germany. • Air curtain nozzles with choked micro-outlets reduce noise and enhance shielding. • Wind tunnel tests assessed nozzle performance on landing gear models at DLR. • Upstream nozzles reduced noise by up to 7 dB in the 1 kHz – 10 kHz range. • High-frequency noise (>10 kHz) increased, revealing a shielding–noise trade-off. • Mass flow rate affected noise reduction; further optimization is recommended.