In-flight boundary-layer state measurements on a high-lift system: Main element and flap

Flight experiments on NASA Langley Research Center's B737-100 airplane were conducted to document flow characteristics for further understanding of the flow physics on multielement high-lift systems, The measurements presented in this paper show that significant regions of laminar flow exist on the main element and the foreflap of the airplane. Flow mechanisms that affect the extent of laminar now include relaminarization of the flow in the leading-edge region of the main element and contamination of the laminar now on the nap by turbulent shear layers emanating from upstream elements. This information should be valuable in the development and assessment of high-Reynolds-number wind-tunnel experiments and numerical models for predicting the flows around multielement wings at full-scale high-lift conditions.