Active Control of Wing-Engine-Slat Cut-Out Region Flow Separation

This paper describes the CleanSky 2 project INAFLOWT. The project aims to investigate an innovative flow control concept, including steady suction and oscillatory blowing, to control the local flow separation taking place downstream of the slat cut-out over a generic high lift wing with integrated ultra-high bypass ratio flow-through engine. The wide slat cut-out causes premature flow separation. A team of five partners performed experiments and simulations on two differently scaled wind tunnel models in a collaborative environment. The baseline flow on the small-scale model has been found to be similar to the one on the large-scale model, despite differences attributed to Reynolds number and wind tunnel wall effects. This work focuses on the small scale experimental results of the baseline flow and the flow with activated steady suction. It is demonstrated that steady suction from nine discrete holes on the inboard side of the engine pylon at 1.5% chord location is capable to provide significant lift recovery, which is in agreement with CFD predictions. We present and discuss here the experimental effort and outline the route to the large-scale wind tunnel experiment, using steady suction and pulsed blowing, in an attempt to reduce the mass flow requirement and fulfil the performance recovery target