MEASUREMENTS OF REYNOLDS STRESS PROFILES ON A HIGH-LIFT AIRFOIL

Reynolds stress profiles are presented for a high-lift airfoil at 9 and 16 million chord Reynolds numbers at multiple angles of attack. A crossed hot-wire probe was used to survey the wakes of the slat and the main element at various stations on the airfoil. A single normal hot-wire probe was used to investigate the small slat wakes and unsteadiness emanating from the cove region. At low angles of attack it appears that flow unsteadiness alters the mean flow profile significantly and that this causes the slat wake to essentially disappear by the end of the main element. Three airfoil configurations were tested. The first, a baseline configuration designated 30P30N, the second designated 30P35T, has an increased flap deflection, and the third designated 30P30AD, has a flap gap change. For 30P30N, at chordwise stations from the middle of the main to the middle of the flap only small quantitative but essentially no qualitative differences were observed in the Reynolds stresses for the different Reynolds numbers. Increasing the flap deflection had a significant effect on the slat wake as it passed over the flap. For the stations surveyed on 30P30AD, only a vertical offset due to the gap change was noted.