分区LES/DES混合方法及缝翼三维流场模拟

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

提出一种分区大涡/脱体涡模拟混合方法,采用高阶空间有限差分方法和二阶隐式LU-SGS时间推进方法,对有限展长缝翼的三维流场进行了数值计算。该混合方法吸收了脱体涡模拟方法和大涡模拟方法各自的优点,在非核心区域使用脱体涡方法进行计算,相对于大涡模拟方法具有较高的计算效率;相对于分区脱体涡模拟中采用的雷诺平均方法,在计算量没有明显增加的条件下提高了对流场各尺度流动的模拟能力。计算结果与风洞实验数据吻合良好,同时缝翼流场主要观测点的压力脉动数据为后续缝翼噪声分析和低噪声优化提供了基础。

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 simula-tion 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 pro-vides basis for further studies in the slat noise analysis and low-noise high lift optimization.