Numerical Investigation of Separation Control for Wing Sections

Abstract

Numerical simulations of the unsteady separated flow over wing sections at flight Reynolds numbers are challenging. Direct numerical simulations which resolve all scales of the fluid motion promise the highest degree of fidelity but are computationally very expensive. Even large-eddy simulations can be prohibitively expensive because of the high grid resolution required near the walls. Hybrid turbulence models employ Reynolds-averaged NavierStokes near the walls and adjust the turbulence model contribution away from the walls according to the local physical grid resolution. In this paper hybrid simulations based on a one-equation renormalization group model are presented for a modified NACA643-618 airfoil at a chord Reynolds number of 1 million and for 10, 20, and 30 degrees angle of attack. For these conditions a short laminar separation bubble develops near the leading edge and the flow separates turbulent from the suction side downstream of the leading edge bubble. For 10 degrees angle of attack the lift and drag data obtained from the simulations are in good agreement with XFoil predictions and active flow control by harmonic blowing through a spanwise slot upstream of the turbulent separation is investigated.

Numerical Investigation of Separation Control for Wing Section at Re=300,000

“…[6][7][8] The experiments were complemented by simulations for Re=64,200,9,10 Re=322,000, 11,12 and Re=1 Million. 13 The full-size cruise Reynolds number is 3.2 Million. Thake et al 14 investigated separation control by steady vortex generator jets for the original NACA 64 3 -618 airfoil.…”