A wall-modelled large eddy simulation approach based on large scale parallel computing for post stall flow over an iced airfoil

Abstract

Safety evaluation for ice accretion is one of the most important jobs for the airworthiness certification of commercial aircraft. Ice accretion would induce strong performance degradation of lifting surfaces by modifying the geometry of the leading edge and the state of boundary layers, and inducing premature flow separation. In this paper, a wall-modelled large eddy simulation (WMLES) approach combined with high performance computing is presented and evaluated for numerical simulation of post stall flow at Mach number 0.12 and Reynolds number 3.5 million over an iced airfoil with angle of attack 6 degrees for business jet, which is known as the GL305/944 airfoil with horn ice. Both RANS and an improved DDES (IDDES) based on SST model are also completed to validate the results. The results are compared with the experimental data in details that includes total forces, velocity profile, averaged velocity field, RMS of pulsating velocity, et al. It is concluded that the WMLES approach presented here can greatly improve the numerical accuracy for post stall flow with large separation; Basically, WMLES can relatively accurately predict the total forces, the pressure rooftop length and the pressure recovery, and the shear layer instability induced by the horn ice.The relative error of lift coefficient for WMLES is only 0.47%, which is far less than RANS with -26.7%.