Aeroacoustic Noise Analysis And Noise Reduction Method Of Landing Gear Under Plasma Excitations

With rapid development of civil aviation industry in our country,aircraft noise directly affects the difficulty of airworthiness certification and its market competitiveness in recent years.Carrying out research on the aerodynamic noise related to landing gear and its structural components is of great significance to the development of general aviation industry.In this paper,a nose landing gear of a certain aircraft is used to simplify some characteristics of the landing gear,and a model of four components of tire,fork,torsion arm and strut is established.Through the derivation process of Lighthill equation of aerodynamic acoustics was expounded and the generation mechanism and simplified model of plasma flow were analyzed.The combination of electric field force of plasma flow and volume force of N-S equation was used to provide theoretical support for the analysis of noise reduction method and calculation method.The static pressure distribution of landing gear,velocity section distribution and turbulent kinetic energy distribution around the landing gear are obtained by the method of Detached Eddy Simulation.Combined with the FW-H equation integral extrapolation,the far-field sound field distribution of the landing gear model is obtained.The noise source contains a large number of dipole and quadrupole sourcesAiming at the main noise source of landing gear flow,a plasma noise reduction method is proposed.The electric field force is compiled into the numerical simulation method by UDF,and the appropriate voltage intens ity and electrode frequency are set to ensure that the plasma noise reduction method effectiveness.Different intensity of plasma flow is used to analyze the noise reduction effect aiming at the model.Through the simulation gaining the flow field and spectral characteristics,compared with different conditions of the noise reduction effect,it is concluded that the intensity of the plasma flow has a noise reduction effect when the intensity of the plasma flow is similar to that of the flow field.An excessively strong plasma flow will impede the flow and cause a new noise source.The proper intensity plasma flow can achieve 3.85% and 1.70% noise reduction effects on landing gear noise at the two observation points,which provides reference for the research on active noise reduction methods of the landing gear.