Numerical study on coupling effect of landing gear and cavity noise

This paper aims at researching the influence of rectangular cavity (gear bay) on landing gear noise. The unsteady flow field and aerodynamic noise from a two-wheel landing gear named LAGOON is simulated by applying LES model and FW-H equation. Good agreement is achieved between the numerical simulation and wind tunnel measurements in case of aerodynamic and aeroacoustic results. According to the size of LAGOON, a simple rectangular cavity is designed as the gear bay of it. Both the gear bay combined with the landing gear and the cavity alone are simulated in the same way. The noise level will increase 5-10 dB when adding the cavity to the landing gear. The contribution of different noise sources is analyzed separately. It turns out that the existence of cavity has little influence on the noise radiated from landing gear. However, the existence of landing gear increases noise from cavity notably. The main noise source of the cavity is positioned at the upper part of the after wall due to the impingement by shear layer. The pressure fluctuation of this part is enhanced when coupling landing gear is inserted into the cavity, leading to the increase of far-field noise.