Reynolds Stress Transport Modeling for High-Lift Airfoil Flows
Numerical predictions of high-lift airfoil flows are performed on refined grids using a Reynolds stress model that is a variant of Launder and Shima model [Launder, B. E., and Shima, N., "Second Moment Closure for the Near Wall Sublayer: Development and Application," AIAA Journal, Vol. 2710, 1989, pp. 1319-1325.] and a standard k - ∈ model. In this study, the test case of the turbulent flow over the A-airfoil designed by Aerospatiale is considered. Three incidence angles 7.2, 13.3, and 15.3 deg, which correspond to attached and separated flows, are examined for analyzing the performances of the Reynolds stress turbulence model. In particular, emphasis is put on the case 13.3 deg near the static stall which constitutes a challenging test in turbulence modeling since the flow presents complex physics such as a laminar separation bubble, a turbulent reattachment, and a turbulent separation near the trailing edge. Comprehensive comparisons with wind tunnel experiments for the lift and drag coefficients, the pressure and skin friction distributions, as well as the computed velocity, and Reynolds stress turbulent profiles, are worked out. Special attention is devoted to the evolving profiles of the velocity and the turbulent stresses in the boundary layer at six locations on the suction side of the airfoil for incidence angles 7.2 and 13.3 deg. As a result of interest, it is found that the Reynolds stress model predicts both attached and separated flows in a very good agreement with the experimental data. As expected, the k - e model reveals very poor performance near the static stall.