Microvortex generators in high-speed flow

A review of the state-of-the-knowledge of microvortex generators (MVGs) and their effect on separated shock/boundary-layer interactions is provided. The flowfield around and behind an MVG is discussed, paying attention on the major and minor vortical features. A detailed discussion is provided of the MVG wake where symmetry breaking and Kelvin–Helmholtz instability give rise to unsteadiness characterized by large, vortex ring structures. While MVGs are thought to be effective in reducing the separation zone, details of how they affect the separation zone remain to be understood properly. Ideas on how the MVG affects separated shock/boundary-layer interactions are reviewed. The review suggests that further optimization studies are needed to put MVGs to practice. In addition, performance metrics are proposed.