Flow Control and Passive Low Noise Technologies for Landing Gear Noise Reduction

This paper examines the use of both flow control and passive low noise technologies to reduce the aerodynamic noise radiated from a modified LAGOON landing gear, as tested in the EU funded H2020 collaborative research project: INVENTOR, InnoVative dEsign of iNstalled airframe componenTs for aircraft nOise Reduction. 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 noise abatement measures which could be retrofit to existing landing gear configurations. Flow control in the form of low TRL "air curtains" which form a fluidic shield or virtual fairing are examined. Amongst the most interesting passive solutions are a selection of higher TRL porous materials in the form of wire mesh, perforated plates and 3D materials. In order to provide a simplified baseline landing gear mock-up on which to test the low noise technologies, the LAGOON NLG is modified with the addition of a torque-link and brakes and is called the "LAGOON-SLG". The porous materials are assessed experimentally in the A-Tunnel aeroacoustic facility in TU Delft, the Netherlands and the air curtains are examined in DLRs AWB aeroacoustic facility in Braunschweig, Germany.