Three-Dimensional Analysis of Vortex Generators for Load Alleviation at Transonic Speeds

This study investigates the load alleviation performance of the spoiler function of switchable vortex generators (SVGs) in transonic conditions. Using three-dimensional computational fluid dynamics (CFD) simulations, the effects of design parameters—including the height, aspect ratio, and spacing between the vortex vanes—are analyzed on an unswept wing with a supercritical cross section. The results demonstrate that finite-span spoiler devices such as SVGs can effectively reduce lift at high speeds, though their performance is highly dependent on geometric characteristics. Distinct aerodynamic regimes can be induced by SVGs placed on the upper surface, characterized by different degrees of flow separation downstream of the device. Significant lift reduction is only observed when the vane size is sufficient to trigger full flow separation. In arrays of SVGs, the interaction between devices is strongly influenced by their spacing, size, and wall ratio. Large SVGs can be operated at low wall ratios, as they can induce flow separation independently, while smaller SVGs perform well in denser configurations, where mutual interactions contribute to a more uniform separation across the upper surface.