Drag Reduction in a Slanted Ahmed Body using Rod Inserts.

This work investigates the impact of the installation of rod inserts on the aerodynamic drag of a 1:30 scaled 25° slant angle Ahmed body (SAAB). The research was accomplished using planar particle image velocimetry measurements of a SAAB model in a water tunnel, complemented with finite element-based COMSOL Multiphysics simulations. For each methodology, the SAAB was tested at a Reynolds number (based on the SAAB length) of 5.61×10⁴. At a deviation of 2%, the L-VEL Reynolds averaged Navier-Stokes turbulence model was found to best match the basic structural features of the experimental flow results. By modeling the placement of a single row of rods at porosities ranging from 60% to 95%, a proportional relationship between the midspan rear-end recirculation length and the drag coefficient (C_D) was observed. Specifically, the C_D trend was non-monotonic, with a drop of 5% reached when a 95% insert was installed. The results indicate the potential of implementing such rod arrangements in the automobile industry to offer substantive fuel consumption and environmental impact reduction.