A turbulent convective flow of an incompressible fluid inside a staggered ribbed channel with high blockage at ReH ≈ 4200 is simulated with direct numerical simulation (DNS) and Reynolds-averaged Navier–Stokes (RANS) techniques. The DNS results provide the reference solution for comparison of the RANS turbulence models. The k–ε realizable, k–ω SST, and model are accurately analyzed for their strengths and weaknesses in predicting the flow and temperature field for this geometry. These three models have been extensively used in literature to simulate this configuration and boundary conditions but with discordant conclusions upon their performance. The model performs much better than the k–ε realizable while the k–ω SST model results to be inadequate.