With the crisis of energy becoming more severe, the research of cutting down the drag of commercial vehicles is more and more important. In this work, to reduce the drag of a van body truck, aerodynamic drag reduction designs are carried out by the method of numerical simulation. The external fluid flow physics over the complete 360 degree of van body is simulated numerically using CFD code considering various aerodynamic parameters. Spherical dimples are created on the trailer region of the van body in order to reduce drag. The results obtained numerically are validated with the experiments using wind tunnel carried out in the Fluid Machines laboratory of VIT University. Upon validation the numerical study is extended to parametric studies, by changing the size of dimples and distances between them. These modifications on the surface have been studied for their influence on aerodynamic drag, with the motive of reducing it and to conserve the engine power and reducing emissions. The study shows that as the diameter of the dimple are reduced the drag coefficient decreases. Reducing the effective distance between dimples also affects the drag experienced by the body. © Research India Publications.