IN-FLIGHT BOUNDARY-LAYER STATE MEASUREMENTS ON A HIGH-LIFT SYSTEM - SLAT

Flight experiments on NASA Langley Research Center's B737-100 airplane were conducted to document flow characteristics for further understan ding of high-lift now physics. The measurements included surface press ure distributions measured using flush pressure taps and pressure belt s on the slats, main element, and flap elements, and boundary-layer st ate changes measured using hot-film anemometry and infrared thermograp hy. In this paper, results obtained in the final phase of flight exper iments are presented and analyzed. The analysis primarily focuses on c hanges in the boundary-layer state measured on the slat as a result of changes in nap setting and/or flight condition. The measurements show that extended runs of laminar now exist on the slat at relevant angle s of attack. Flow mechanisms that affect the extent of laminar flow in clude attachment-line contamination, crossflow instability, and relami narization.