Zonal LES/DES method and its application in slat flow field simulation

Noise source of high-lift device consists mainly of slat noise and flap side noise. Development of accurate numerical methods is important to the aerodynamic design of low-noise high-lift systems. In this paper, a zonal LES/DES hybrid method is proposed and implemented. High-order finite difference method and three-point backward LU-SGS implicit time marching scheme are employed to solve the flow field of a three dimensional slatted airfoil of finite span. The hybrid method takes advantage of the capabilities of both large-eddy simulation (LES) and detached-eddy simulation with improved efficiency over direct LES method for the complete flow field. The computation efficiency is improved by the use of detached-eddy simulation in the non-core region, and it also helps to capture the details of the flowfield compared to RANS method; large-eddy simulation is implemented in the core region which contains complex flow to improve the simulation capabilities of full-scale flow. Computation results are validated comparing with that of the experiment data, and some analysis is carried out based on the pressure-observer near the slat cove. The research provides basis for further studies in the slat noise analysis and low-noise high lift optimization.