Local Flow Effects on Noise Prediction of Transonic Truss-Braced Wing Landing Gear

The local flow velocity is a primary scaling parameter to the strength of noise sources on landing gear. Airframe geometry, particularly the landing gear integration details can result in large, localized deviations from the freestream velocity. The transonic truss-braced wing aircraft concept presents a unique situation where the main landing gear is integrated into a wing strut rather than the traditional wing- or body-mounted gear. Existing parametric models of the velocity in the gear region are limited to conventional aircraft; application to unconventional configurations has the potential to introduce error into the noise prediction. Reynolds-averaged Navier-Stokes simulations of the flow around a transonic truss-braced wing at several flight conditions comprise a database to model the local flow velocity near the gear. A polynomial function dependent on the distance from the strut and angle of attack is sufficient to model the flow dependence. This model addresses a gap in accurate system noise prediction of this particular unconventional configuration, resulting in a 2.4 EPNdB difference in main gear noise relative to a previously-used model.