Tracking the Nacelle Vortex Above Aircraft Wing in the ETW at Real Mach- and Reynolds Numbers by Means of PIV

Stereo PIV measurements have been performed in multiple planes of the flow above the wing of a high-lift aircraft configuration in order to investigate the performance of strake vortex generators attached to the nacelle with regard to the evolution of flow separations on the main wing at high angles of attack. The measurements have been carried out in the cryogenic pressurized transonic wind tunnel facility of ETW that allows to perform the measurements at real flight Mach and Reynolds numbers by using total gas temperatures and pressures down to 110 K and up to 450 kPa, respectively. Because of this extreme wind tunnel conditions a specific cryo-PIV measurement system has been used. To provide insights into the streamwise development of the vortical flow a light-sheet, oriented perpendicular to the direction of free stream velocity, has been positioned to different chord stations of the wing. This paper focuses on a description of the employed PIV setup in the ETW showing first results for a standard configuration obtained at flight Reynolds numbers.