Physics-based flow control for swept and tapered wings using steady blowing*

Abstract: An experimental investigation of flow control by steady blowing over swept and tapered wings was performed in a series of wind tunnel experiments with a mean-chord Reynolds number of 247,500. Two wings were explored each with a semi-aspect ratio of 2 and taper ratio of 0.269. One wing had an unswept leading edge and a 30 degree swept forward trailing edge and one wing had a 30 degree swept back leading edge and an unswept trailing edge. Both wings were instrumented for steady blowing from seven equally spaced jets across the leading edge. Aerodynamic loads were collected for multiple combinations of jets at a blowing ratio of 1. Volumetric mean flow fields were collected using SPIV to understand the effects of the jets on the large-scale wake structures at an angle of attack of 18 degrees. For the wing with the swept forward trailing edge, a single jet at the third-span location was the most effective at improving lift to drag ratio and alleviating pitch break. SPIV measurements show that this jet acted as a virtual fence, blocking the formation of the tip-to-root inverted ram’s horn structure that has been previously observed to form on this type of wing. Flow control on several planforms will be presented.