Mean Flow Features Around the Inline Wheels of Four-Wheel Landing Gear

摘要: Landing gear are noted to be a signie cant, sometimes dominant, airframe noise source for commercial aircraft. Aerodynamicnoiseis directresultofthee uctuating e owand its interaction with surfacecomponents. Knowledge of the mean ow, however, can used aid in determination sources. The complex geometry multiple-wheel-set landing has thus far precluded even this basic information. In study owe eld is determined streamwise plane surrounding inline wheels generic four-wheel landing-gear cone guration using digital particle image velocimetry. velocity and vorticity elds highlight vortex that persists between on ground side axle midplane. formation believed resultfrom thegeometricasymmetry caused by presenceofthecentersupportstrut.Evidenceis also presented shows does not remain stationary, but oscillates fore aft wheels. Its position hypothesized dependon thestateofan unstablevorticity layerthatdevelopson theground sideoftheforewheel.