One of the primary challenges in hypersonic flights is the intense aerodynamic heating due to shock-wave boundary layer interactions. The flow across surface roughness or protrusions interferes with the freestream flow, leading to a three-dimensional interaction creating flow features such as a bow shock and horseshoe vortex in front of the protrusion. This affects the local convective heating on the vehicle’s surface, particularly on the reattachment region. This study employs an open-source, density-based, second-order accurate finite volume Navier–Stokes solver to simulate the flow around a wall-mounted rectangular protrusion. The numerical results are validated against experimental data. While the RANS-based approach shows reasonable agreement with measured wall heat flux distributions, it exhibits limitations in accurately predicting regions of high vorticity concentration. The computed heat flux distributions reveal elevated values near multiple reattachment lines, including the primary reattachment following the separation shock, secondary reattachments, and side reattachments induced by vortices generated at the protrusion’s sharp edges. The hotspot appears just ahead of the protrusion, where the combined influence of the main and side reattachment flows converge.