Reducing aerodynamic drag is a key objective in engineering design due to its direct impact on fuel efficiency, environmental sustainability, and overall system performance. This study explores drag reduction by addressing both pressure and skin friction components. Initially, numerical simulations using the open-source SU2 solver were performed to validate the drag coefficient of a flat plate perpendicular to the flow. This phase included verifying the simulation setup and conducting a mesh sensitivity analysis. In the second phase, passive flow control was examined using a single surface cavity as a simplified representation of porosity. A parametric study on cavity depth and spacing identified the optimal configuration, 1.5 mm depth and 10 mm spacing, yielding a maximum drag reduction of 10.42% compared to the baseline. The effectiveness of this approach is attributed to cavity-generated vortices that help re-energize the boundary layer. Overall, the findings offer promising insights into geometry-based passive drag reduction techniques relevant to aerospace, automotive, and wind energy applications.