After Market Portable Drag Enablers to Improve Fuel Economy of on Road Car

Aerodynamic performance of on-road vehicle can be improved by using portable enablers on rear portion of the vehicle which can be attached or detached by the owner himself. Objective of this study is to explore the possibility of using such portable enablers to substantially reduce the drag of the vehicle. Enablers with specific convex shapes are created on various positions of rear portion of vehicle and simulated with CFD solver FLUENT. Compact sedan vehicle was considered in this study. Preprocessing is performed and specific fluid domains are captured. Generally, aerodynamic enablers are integrated parts of the vehicle. This paper emphasizes on consideration of portable enablers which can be used while cruising for longer distances. Drag improvement of ΔCD = 0.006~0.009 was achieved by introducing the specific enabler based on its position, shape and dimension. This paper also suggests methods of attachment of portable enabler to the vehicle. Simulation is performed using realizable k-ε model with non-equilibrium wall functions for turbulence modeling. Drag due to heat exchangers is included in the total drag of the vehicle. Standard CFD methodology adopted here has credible correlation for the drag coefficient with the wind tunnel measurements. The comparison plots for pressure distribution on rear portion of vehicle are presented to show the effect of enablers.