Aeroacoustic Analysis of a Simplified Landing Gear

A hybrid approach is used to investigate the noise generated by a simplied landing gear without small scaleparts such as hydraulic lines and fasteners. The Ffowcs Williams and Hawkings equation is used to predict the noiseat far-eld observer locations from ow data provided by an unsteady computational uid dynamics calculation. Asimulation with 13 million grid points has been completed, and comparisons are made between calculations withdifferent turbulence models. Results indicate that the turbulence model has a profound effect on the levels andcharacter of the unsteadiness. Flow data on solid surfaces and a set of permeable surfaces surrounding the gearhave been collected. Noise predictions using the porous surfaces appear to be contaminated by errors caused bylarge wake uctuations passing through the surfaces. However, comparisons between predictions using the solidsurfaces with the near-eld CFD solution are in good agreement giving condence in the far-eld results.