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.