Problems with leading-edge flow control experiments

A guide has been reported for future leading-edge flow control activities conducted in wind tunnels operating at low to medium Reynolds numbers and is specifically applied to civil transport aircraft. The objective of this guide is to provide a review of relevant literature, identify airfoil geometric parameters relevant to designing leading-edge flow control experiments, and describe a wind-tunnel experiment that highlights many of the problems associated with subscale testing of leading-edge flow control. The control experiments regarding Reynolds number of 10 x 106 should be documented as transition control and not separation control, unless alternative ways are found to turbulate the flow while ensuring that the turbulence level is representative of flight conditions.