Numerical Investigation of Air Jets for Dynamic Stall Control on the OA209 Airfoil

Abstract

The design and numerical investigation of constant blowing air jets as Fluidic Control Devices (FCDs) for helicopter dynamic stall control is described. Prospective control devices were first investigated using 3D RANS computations to identify effective configurations and reject ineffective configurations. Following this, URANS investigations on the dynamically pitching OA209 airfoil verified that configurations had been selected which reduced the peaks in pitching moment and drag while preserving at least the mean lift and drag from the clean wing. Two configurations using jets at 10% chord on the airfoil top were identified, and one configuration using a tangential slot at 10% chord on the airfoil top, with each configuration evaluated for two jet total pressures. For the best configuration, a reduction in the pitching moment peak of 85% and in the drag peak of 78% were observed, together with a 42% reduction in the mean drag over the unsteady pitching cycle.