Parametric Study of a Switchable Vortex Generator for Load Alleviation in Transonic Conditions

This paper investigates the impact of introducing a switchable vortex generator (SVG), acting as a minitab, on the aerodynamic performance of a high-aspect-ratio wing’s outer section in transonic regime. A parametric study is conducted employing computational fluid dynamics two-dimensional simulations, focusing on the aerodynamic effects of changing the chordwise position and height of the vane of a SVG located on the airfoil upper surface in both nominal cruise conditions and for varying angles of attack. The analysis reveals that minitabs can strongly affect the aerodynamic forces produced by the wing section, showing great potential for load alleviation and control, but also emphasizing the need for a careful parameter selection to reduce undesirable effects such as the generation of shock waves. In cruise conditions, lift reduction increases with the vane height and has its maximum for chordwise positions at 60% of the chord length. However, SVGs located in the first half of the chord length yield more robust performance for varying angle of attack, without sharp lift variations or generated shock waves, and a delayed stall onset. High SVGs (greater than or equal to 3% chord length) can also lead to strong shock waves on the airfoil lower surface at small or negative angle of attack, while small SVGs (less than 1% chord length) can generate normal shock waves on the upper surface, with limited lift reduction in cruise conditions and at higher incidence.