A DNS study on the Mach number effect for a supersonic microramp

Microvortex Generators (MVGs) are passive control devices with heights below the boundary layer thickness that have been proposed to mitigate the detrimental effects of Shock Wave/Boundary Layer Interaction (SBLI). Although their control effectiveness has been largely demonstrated, several aspects of the flow generated by MVGs in supersonic boundary layers still need to be characterized. In this work, we present a campaign of Direct Numerical Simulations (DNSs) of a turbulent boundary layer on a microramp, to investigate the effect of the Mach number, from subsonic to the supersonic regime. An in-depth analysis characterizes the properties of the flow generated by the microramp, showing that the flow topology changes significantly because of compressibility effects, and that typical wake features do not scale linearly with the geometry dimensions but rather depend on the incoming flow conditions as well.