This work makes an attempt to determine an effective streamwise and spanwise arrangement of a relatively novel control device, the sub-boundary-layer slotted vortex generator, having a slot radius of 60% of device height, to minimize the flow separation in a realistic mixed-compression inlet geometry. The inlet considered for the simulations is based on the experiments conducted by S. Emami et al. at NASA Langley Research Center at Mach 4.03 to determine performance of an inlet/isolator configuration. The present work uses a computational domain based on one such inlet configuration, having the smallest-sized cowl and a large convergence angle, to produce a strong cowl-lip shock. Results indicate that the extent of flowseparation gets successively reduced, as the device trailing edge ismoved closer to the interaction region. It is also observed that the inlet width determines the optimal spacing of the device, and that in presence of sidewall boundary layers, the device performs better when positioned closer to the inlet center plane than the sidewall. The computations in thiswork are performed using the REACTMB code, suitable for high-speed turbulent flows. The turbulence model used is Menter's shear stress transport model. Copyright © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.