A flat plate rectangular wing subjected to grid - generated turbulence

Micro air vehicles (MAVs) are low speed, small, remotely piloted aircraft designed for low altitude reconnaissance and sensory missions. The low speed flight through the lower levels of the atmospheric boundary layer results in relatively high turbulence levels and low Reynolds numbers. In recent studies of low Reynolds number airfoils, the effects of turbulence are rarely considered nor replicated, since traditionally aeronautical testing is almost always conducted in smooth flow. In this paper turbulence intensities comparable to those experienced by MAVs flying at low speed and altitude are replicated via grids in a wind tunnel. A thin, pressure-tapped, flat-plate aerofoil was used to investigate the effects of Reynolds number and turbulence on coefficients of pressure, lift, drag and pitching moment. The lift at high angles of attack was found to increase with raised turbulence intensity, although a drag penalty was incurred.