The Aerodynamic Noise Analysis Of A Landing Gear With Tires

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 significance to the development of general aviation industry.The establishment of grid and a three-dimensional geometric model with a tire and its detailed features is completed.The landing gear noise generation mechanisms and the characteristics are researched.The thesis has the following major contents:Noise characteristics,prediction methods and reduction of the landing gear noise are reviewed based on current research status at home and abroad.The difficulties and problems are pointed out.Basic principle of landing gear noise generation mechanism is analyzed from the mathematical method based on fluid dynamic and acoustic.The control equations of the flow field and sound field around the landing gear in the later simulation are established.The solving means are given in detail.The Detached Eddy Simulation(DES)is applied for the landing gear noise simulation.The flow parameters in the flow field,the noise source intensity and location in the near sound field,the spectra results in the far field sound field are derived.Noise generated from the turbulent field around the landing gear and its acoustic characteristics are deeply understood via detailed analysis of the simulation results.Through comparison between the simulation results of this paper and the simulation results of the landing gear structural model without the tire,further research with the tire and its detailed features of the landing gear model are finished.Comparing the results between simulation and experiment by the predecessors,the simulation feasibility is verified.It is concluded that the total noise spectrum and tire noise spectrum is the most close,the farther the horizontal distance is and the smaller the sound pressure amplitude will be.The noise contribution amount of pillar and the torque arm is affected by the addition of the tire with a figure of 60% and 45%.