Characterization of Noise Generation on a Canonical Nose Landing Gear Sub-system

Abstract

A series of aeroacoustic experimental and computational measurements were conducted for the case of flow around a complex, three-dimensional landing gear sub-system. The model under study is a canonical representation of a nose landing gear torque link apparatus that is present on numerous commercial aircraft. Experimental measurements consisted of model steady and unsteady surface pressures, far-field acoustic measurements, and three-dimensional flow field velocities using stereoscopic particle image velocimetry. The experiments were also accompanied by computational fluid dynamics simulations using PowerFLOW software, a lattice-Boltzmann solver. The computational aeroacoustic capabilities of this software were also utilized to predict the far-field acoustic radiation via a built-in Ffowcs-Williams and Hawkings solver. Excellent agreement between the simulation and experiments have been obtained for surface pressure measurements, mean flow field behaviors, and far-field acoustics. A modified linear stochastic estimation procedure was implemented on the SPIV data to develop a low-order time-resolved estimate of the acoustic source terms of the vortex sound analogy.