Experimental investigation of the formation of secondary flow structures and interactions of a finite-span synthetic jet in a cross-flow at chord-based Reynolds numbers between 50,000 and 400,000 and angles of attack from 00 to 200.

Drones and High Altitude Long Endurance vehicles typically operate at moderate to high Reynolds numbers based on airfoil chord length, i.e., Rec ≈ 105 to 106. These vehicles are becoming increasingly important to applications like national security-related surveillance, search and rescue in dangerous terrain, scientific research, and animal conservation, among others. As such, the understanding flow conditions in such a way to ensure the safety of these aircraft is of paramount importance.

experimental investigation was performed to study the formation of secondary flow structures due to the interaction of a finite-span synthetic jet with a three-dimensional boundary layer over a finite and swept-back wing configuration (cross-sectional profile of the NACA 4421, aspect ratio of 4 and sweep back angle of 30o).

Separation is an adverse aerodynamic phenomenon resulting in loss of aerodynamic performance. Previous studies on separation have mainly dealt with a two-dimensional analysis due to the assumption that the third dimension was negligible or that it was too complicated to analyze, leading to an incomplete analysis. Literature has indicated however, that this is insufficient in understanding separation and needs to be studied as such as spanwise instabilities have been shown to play a major role in the flow field and physics.