Analysis of URANS capabilities on modeling airfoil pitching flows

Abstract

Abstract – This document describes the investigation of the behavior of the flow over a pitching NACA 0012 airfoil at Reynolds number Re=100,000 and Re=2,500,000 of the analysis of a two-dimensional k-ω SST (Shear Stress Transport) simulation. The behavior of the flow wake at the trailing edge is studied by the analysis of streamlines for each incidence angle and results are compared by the study of theoretical concepts and experimental data. The use of standard Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation has shown accuracy in predicting stall and reattachment incidence angles for upstroke and downstroke. The simulations were also capable of capturing flow information in agreement with experiments despite the over prediction of lift and drag coefficients, due to the two-dimensional simplification. The study has also compared the two-dimensional URANS k-ω SST turbulence model simulation data with previous results from three-dimensional simulation Wall Resolved Large Eddy Simulation (LES) and two-dimensional URANS k-e Chien turbulence model analysis, showing that the qualitative behavior of the hysteresis loop is close for the computations, although there is a quantitative deviation in the results for upstroke and downstroke in the lift coefficient.