Analysis of aeroacoustics characteristics of high lift device using LES method

The accuracy of flow field has a significant impact on the details of vortex turbulence and aeroacoustic calculation results. LES method is used for high lift device flow field simulation, and Ffcows Williams-Hawkings integral surface is used for far-field noise calculation. In this paper, numerical results are validated comparing with test results of flow around cylinder, comparison shows that LES method used in this paper can capture unsteady flow like vortex shedding and detachment, and provide accurate near field flow solution for the following far field noise calculation, acoustic analogy based on FW-H equation can solve far-field noise accurately and efficiently. Based on this, the flow characteristics, far-field characteristics and flow speed influence of high lift device noise generation are numerically studied in this paper. Results show that the slat noise is mainly caused by the unstable turbulence between slat and main element of high lift device and slat trailing edge vortex shedding; while the flap noise is mainly caused by small scale high frequency and large scale low frequency vortices generated around the flap.