Separation Control on Oscillating Airfoils Using Moving Surface Control

Abstract

A numerical investigation has been conducted to study the effectiveness of Moving Surface Control method in controlling dynamic stall in oscillating airfoils. The momentum imparted by the moving surface to the free shear layer is utilized for dynamic stall vortex suppression. In this way, effective flow control is achieved and adverse effects of dynamic stall are eliminated. The results are of interest as they provide insight into flow control for airfoils operating under unsteady conditions. Particular emphasis has been laid on the applicability to delaying I suppressing dynamic stall on rotorcraft blades to avoid extreme stresses and broadband noise radiation. The numerical study was based on the solution of 2D RANS equations using Baldwin-Lomax turbulence model and a solver based on Beam-Warming approximate factorization technique. The effect of moving surface flow control was analyzed with reference to control strength as well as reduced frequency of airfoil oscillation. For the finite time, moving surface control was applied successfully to achieve effective control of the dynamic stall phenomenon in oscillating airfoils at a realistic Reynolds' number (Re=l06).