Aerodynamic Tests Conducted on a Large-Scale Nose Landing Gear and Cavity Model in the ARA Transonic Wind Tunnel

Flow diagnostics capability for the ARA Transonic Wind Tunnel has been enhanced through the procurement and development of several state-of-the-art measurement systems, commissioned through an investigation of cavity flow physics funded by the UK government Department for Business, Innovation and Skills. New techniques have been trialled on a large scale, civil nose landing gear / cavity model designed, manufactured and tested by ARA, providing a database of test cases for the future development of computational aerodynamic and aeroacoustic tools by UK industry. Consistent high quality unsteady data has been obtained from pressure transducers, hot-wires, door and strut balances, high-speed video, and 3-D PIV, with a range of data analysis and presentation techniques demonstrated. A new correction methodology for hot-wire measurements in a transonic pressurised wind tunnel is briefly described. For cavity flows, both internal and shear layer resonances have been identified using unsteady pressure data. The significant effect of Mach Number on frequency, dominant mode and mode shape emphasises the need for high-speed testing of landing gear configurations. Analysis of data gathered in the test has shown that the largescale model with multiple gear & door positions is an ideal vehicle for investigating unsteady flow physics phenomena associated with landing-gear. It is believed that the flow physics observed with this model are representative of those observed in flight, implying that the model and associated diagnostics can be used to inform aircraft design decisions.