Computational and Experimental Study on Noise Generation from Tire-Axle Regions of a Two-Wheel Main Landing Gear

Abstract

The purpose of this paper is computational and experimental investigation of flowfield related to noise generation mechanism from tire-axle regions of a two-wheel main landing gear. Flowfield around tire-axle is complicated with the existence of complicated geometries such as torque link, brake-caliper, and wheel cap. The unsteady flowfields around tire-axle are investigated with change of the torque link setting by unsteady CFD computations on the detail geometry. Three configurations; (1) baseline configuration with backward torque link, (2) configuration without torque link, and (3) configuration with forward torque link are computed. The contributions to the noise level and the directivity of the noise are investigated by the computations and far-field noise measurements. By the computations and wind tunnel tests, the characteristics and physics of the noise from the tire-axle regions of a two-wheel main landing gear are discussed. NomenclatureC P = pressure coefficient FW-H = Ffowcs Williams and Hawkings OASPL = overall sound pressure level R Aircraft = distance to evaluation location of far field noise at aircraft-scale R Model = distance to evaluation location of far field noise at model-scale Re = Reynolds number RTRI = Large-Scale Anechoic Wind Tunnel in Railway Technical Research Institute SPL = sound pressure level T = free-stream temperature U inf = free-stream velocity U Aircraft = aircraft speed U Model = free-stream velocity of wind tunnel test VR = variable resolution

Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

“…The present results are in consistence with the experimental ones. Overall, it is comparably good with the one from the up-wind scheme but B-spline [10] Upwind [20] Fig. 7 Ensemble averaged streamwise velocities at y = 0.…”

“…These flow properties require very fine meshes and the low-dissipation numerical schemes in LES, since the location of the transition point is very sensitive to numerical dissipation. Large numerical dis-sipations could delay the transitions and increase the lengths of laminar shear layers [10]. The noise calculations raise two more challenges: the broadband dipole noise generated by pressure fluctuations on the cylinder surfaces and the broadband quadrupole noise by turbulent wake structures.…”

Numerical Simulation of a Two-Wheel Main Landing Gear with Low-Noise Fairings around Tire-Axle Region

“…They found the largest contribution of the torque arm to the noise level and difference of SPL in the mid-and high-frequency range between fully-dressed and partially-dressed configurations. JAXA has conducted research work on noise generation mechanism and reduction technologies about two-wheel landing gears since 2008 [9][10][11][12][13] . The research model geometry is based on the current two-wheel landing gears design for regional jets.…”

Effect of Cavity Flow on Landing Gear Aerodynamic Loads

“…Although, the NLG geometry is not as detailed as a realistic landing gear, the present case is geometrically complex when compared to previous configurations which were utilized to study cavity flow 15 . A number of previous studies involving simulation of complex NLG were found in the literature [16][17][18][19][20][21][22][23] . However, in those studies, cavity flow associated with the NLG was not considered.…”