Large-eddy simulations of a vortex generator embedded upstream of a normal shock boundary-layer interaction followed by a subsonic diffuser were conducted. In particular, the ""ramped-vane"" flow control device was placed in a supersonic boundary layer with a freestream Mach number of 1.3 and a Reynolds number of 2400 based on momentum thickness. The ramped vane had a height of 0.52 delta and generated strong streamwise vorticity that entrained the high-momentum flow to the near-wall region. This contributed to decreasing the shock-induced flow separation while significantly increasing the skin friction coefficient in the diffuser where a strong adverse pressure gradient was present. In addition, it was found that the high-momentum flow persisted far downstream of the shock interaction region, which yielded reductions of both the displacement thickness and the shape factors compared to the uncontrolled case.