The aerodynamic and aeroacoustic effects of a landing gear door on landing gear noise is determined using a high order, in-house, compressible N-S solver using DES. The results obtained will help provide additional information to the landing gear noise prediction code present at the technology centre. Acoustic analysis is done by applying several integration surfaces that are used to perform FW-H calculations to predict the far-field noise.
The simulations have been carried out on a simplified geometry modelling the interaction between a landing gear strut and door. The results show that the presence of the door affects the shedding characteristics of the strut, which in particular cases leads to a reduction in the overall noise generated.
The present implementation of a landing gear door in the noise prediction code models the landing gear door as a flat plate inline with the flow and scattering the noise generated by the turbulent boundary layer convecting past its trailing edge. On Airbus landing gears, the door is placed at an angle offset from the bogie wheel-line axis. This suggests that the door may be generating bluff body noise due to the shedding behind an inclined surface.
The literature on the interaction between bluff bodies near a flat plate boundary are clear, in that the shedding off a bluff body can be changed. Therefore a similar behaviour is expected in the interaction present for this project. The landing gear system is complex and the effect of the door is believed to be greatest on the landing gear strut. The geometry used for the study was a spanwise extrusion of a two dimensional profile, outlining the exact measurement of the Airbus landing gear door and strut, taken from the upper section of the strut.
The present studies have shown that the landing gear door may modify the noise generation of interacting components. Further studies will be conducted to see whether this behaviour is still present with a model of increased complexity.