Computational Investigation of Drag Reduction on An Ahmed Body Using Square Grooves

Abstract

In Pakistan 96% of the freight transportation is done through trucks. These bluff body vehicles do not have a streamlined shape and hence have a high pressure drag. This aerodynamic pressure drag causes up to 15-20% extra fuel consumption. Aerodynamic drag can be reduced by using different passive techniques of fluid flow control. In this paper, the influence of square grooves on the passive drag reduction has been evaluated. In the first phase simulations have been performed to investigate the skin friction coefficient of smooth flat plate with square groove in it. These grooves are placed transverse to the incoming flow. This results in increasing the friction drag along the boundary causing the transition of laminar flow to turbulent. Similar technique is used in the second phase around a square back Ahmed Body and then finally on a scaled model of Pakistani dumper truck. The study has been conducted with computational fluid dynamics (CFD) simulations using ANSYS Fluent. Unsteady Reynolds Averaged Navier-Stokes (URANS) formulation has been employed in the simulation. The focus of this study is to help the transportation sector of Pakistan by making efficient aerodynamic design. This study is applicable to Pakistani heavy transport vehicles with an intention to reduce the high fuel consumption which is caused due to high pressure drag