基于IDDES方法的翼型结冰失速分离流动数值模拟

应用基于k-ωSST湍流模型的IDDES(Improved Delayed Detached Eddy Simulation)方法,就失速点附近翼型前缘典型双角状积冰导致的复杂分离流动进行了数值模拟研究.通过与风洞试验结果进行对比,表明对于此类分离流动问题,IDDES方法能够在壁面附近取得良好的速度预测结果,有效解析分离区域内的中小尺度湍流结构,较为准确地描述大尺度时均分离泡的再附位置和形态特征,适用于翼型结冰后复杂流动的精细分析.同时计算结果显示当此带冰翼型位于失速点附近时,角状冰后方脱落剪切层内部的旋涡不稳定析出和输运过程促进了外部流动与回流区域流动间的掺混,将导致流动发生非定常再附现象.

Numerical simulation of the stall separated flow around an iced airfoil based on IDDES

The accurate prediction of complex flow phenomena leading by ice accreting of airfoils demands the improvement of turbulent flow prediction methods.The improved delayed detached eddy simulation (IDDES)based on the SST turbulent model is applied in the study of numerical simulation about complex stall separation flow cased by a typical dual horn ice on the leading edge.Comparing with the experimental measurements,numerical simulation results show that IDDES can achieve good prediction results near the wall,effectively resolve middle and small scale vortex structures in the flow separation area and more accurately describe the reattachment position and shape characteristics of the large scale time-averaged separation bubble for such separation flow problem.It is demonstrated that the method is suitable for the analysis of the complex flow after the airfoil icing.At the same time,the calculation results show that when the iced airfoil is near the stall point,the unstable vortex separation and transport process of the shear layer behind the horn ice promote the mixing between the external and reversing flow regions.This effect leads the unsteady reattachment phenomenon of separated flow.