Numerical simulations of single and tandem wheels for aerodynamic loads prediction

The aim of this work is to improve the accuracy and effciency of unsteady aerodynamic loads prediction of landing gears in fight conditions, as part of the UK ATI ALGAAP (Advanced Landing Gear Aero-loads and Aero-noise Prediction) project. Delayed Detached-Eddy Simulations (DDES) with the Spalart-Allmaras turbulence model are performed to obtain the desired prediction improvement, both with the fully-turbulent in flow and with laminar in flow and fixed transition. The reference geometries for the current simulations are generic scaled landing-gear wheels in single and tandem configurations, which have been experimentally tested within the project. An experimental database, consisting of mean and unsteady aerodynamic loads, on-surface pressures and velocity fields from particle image velocimetry, is used for CFD validation. The results show the importance of modelling the transition in order to reproduce the experimental data in the transitional regime and to correctly capture the physical flow features. The proposed high-effciency DDES simulations improve the accuracy of the results with respect to the standard DDES model both on single and tandem wheels. The discrepancy between simulations and experiments on the total mean drag coefficient of tandem wheels is within 7% at zero angle of attack and up to 15% at higher angles of attack.