Airframe noise prediction with installed landing gear for a complete aircraft

The reduction of landing gear noise of aircraft on approach has been a focus of the aerospace community for many years. The present paper describes a method that predicts the noise from the landing gear, accounting for local flow variations due to the wing geometry, the interaction of the landing gear wake with high-lift devices, and a method for approximating the shielding of noise caused by the landing gear geometry. The prediction of the landing gear noise is performed using the Landing Gear Model and Acoustic Prediction code (LGMAP) developed at The Pennsylvania State University. A line of sight algorithm based on scattering by a two-dimensional cylinder approximates the effect of acoustic shielding caused by the landing gear. Two-dimensional FLUENT calculations of approximate wing cross-sections are used by LGMAP to compute the noise change due to the change in local flow velocity in the vicinity of the landing gear. A three-dimensional immersed boundary CFD calculation of isolated LGMAP representations of landing gear geometries provides relatively quick estimates of the mean flow features caused by the landing gear for the prediction of trailing edge noise associated with the interaction of the landing gear wake with the high lift devices. Comparisons with measurements show the accuracy of the predictions of landing gear noise levels and directivity. Airframe noise predictions for the landing gear of a complete aircraft are described.