Aerodynamic Noise Calculation Of Landing Gear Based On The Coupled Method

Aerodynamic noise from the landing gear is the main noise source of civil aviation aircraft now,for example it even becomes the main part of the aircraft noise for some wide-body jets. Therefore,study on the landing gear noise, especially on the flow characteristics and mechanism of noisegeneration, has a great worth of engineering application.Detached eddy simulation (DES) is used to solve the flow field, where S-A model is used as theturbulence model; LES model of Smagorinski combining with S-A model is implemented in otherregions. And the dissipative term of surface in S-A model is appropriately modified, which makes theimproved model is not only acted as S-A turbulence model in RANS, but also acted as LES model ofSmagorinski. In order to capture the small vortex accurately, grid scale must meet the practicalrequirements, which enables the grid to meet the requirements of boundary layer thickness.Based on the above research methods and the unsteady RANS equations of fluid-structurecoupling method, the flow field and sound field of the noise characteristics of a certain type of aircraftmain landing gear components are studied in the paper. The landing gear structural noise behaves thecharacteristics of broadband noise, power spectral density and acoustic pressure level curve increasesas flow velocity enlarges. Using the coupled method, flow field around the landing gear is numericallysimulated; pressure oscillation and coefficient of sound pressure level from the bottom of the landinggear are shown by numerical calculation of flow field, sound field simulation and their correspondingcases under yaw conditions.Finally, Cp figure, vorticity diagram, flow chart and the sound pressure curve are shown in thepaper and comparisons with the results in the literatures are made, which is very meaningful for theresearch on flow field and sound field of landing gear. Also, it can provide data support to reduce thelanding gear noise.