Aeroacoustic Noise Analysis And Noise Reduction Method Of A Landing Gear Structure

Large aircraft is the focusing project of the development of our country in recent years. Aircraft noise directly affects the certification of civil aircraft and its market competitiveness. In the process of landing, the landing gear acoustics noise is one of the important parts of aircraft noise. Therefore, it is important to carry out the research on the development of the acoustics noise about landing gear and its structure, which is of great signif icance to the development of general aviation industry. In this paper, the influence of the strut of the typical components of aircraft landing gear and the aerodynamic noise of the landing gear is studied. The aerodynamic noise analysis model is established by means of numerical simulation.Detached Eddy Simulation combined with Spalart-Allmaras equation is performed to obtain the flow field characteristics including velocity, pressure and turbulent kinetic energy of the flow field around the the landing gear structure including strut and torque link. The noise f ield is calculated via FW-H equation integral extrapolation of Lighthill sound analogy to obtain the frequency spectra characteristics and the radiation directivities of the noise. The simulation results show that the noise radiating from the structure inc ludes bluff body noise and interaction noise and it has the radiation characteristics of a dipole source.In order to reduce the acoustics noise of landing gear effectively, according to the occurrence mechanism of the acoustics noise of landing gear, the noise reduction scheme based on torque arm edge jet is proposed in landing gear, established the adding jet configuration of the landing gear structure model, set the appropriate jet veloc ity to ensure the effectiveness of jet. The influence of the jet on the noise of the structure is studied by numerical simulation. Characteristics of flow field,spectrum characteristics of sound field and overall sound pressure level of the structure were obtained by simulation. Through the comparision of the original wor king condition and the noise reduction method, indicating that the addition of jet changes the around flow field of the landing gear structure and effectively reduce the noise of bluff body and the interference noise of the landing gear. Through the comparative analys is of the noise reduction's effect of different working conditions, the jet velocity range of effective noise reduction is obtained.The results can be the foundation of landing gear aeroacoustic noise study and references of the low noise landing gear design.