Investigation of Drag Coefficients for Various Car Models

The main motivation to pursue this research was to reduce the aerodynamic drag of vehicles so that it may lead to better fuel efficiency. The aim of this research was to investigate the aerodynamic forces on various car models through Computational Fluid Dynamics (CFD) and then validating those results experimentally in a wind tunnel. Two car shapes were chosen based on the commonly found Toyota Corolla EU (2014) and Toyota Land Cruiser 200 (2016). These shapes remodeled with the help of CATIA V5 and Design Modeler. These models were then analyzed using ANSYS FLUENT 14 with different grid sizes until mesh independence was achieved. The results obtained for the drag coefficients were 0.354 and 0.265 for Toyota Land Cruiser 200 and Toyota Corolla respectively. The analysis was done at a wind speed of 20 m/s. The results of the numerical investigation were validated by the already tested values available in the literature, which are 0.35 and 0.27 for Toyota Land Cruiser 200 and Toyota Corolla respectively. For wind tunnel testing, these models were scaled and then 3D printed to be tested in a subsonic wind tunnel. The scale of the models was set to be 1:37 as dictated by the constraints of the wind tunnel. The results obtained during experimentation are comparable only qualitatively nevertheless, a drag coefficient of 0.36 and 0.42 were obtained for Corolla and Land Cruiser 200 by wind tunnel testing. Furthermore, based on our investigation different physical drag reduction techniques were applied to reduce the drag on these models and analysis was performed using CFD. A reduction of 6.26% was observed in the value of drag coefficient by modifications in the Corolla car model.