A CFD Simulation Approach for Optimizing Front Air-Dam to Improve Aerodynamic Drag of a Vehicle

The front air-dam diverts the airflow flowing through the underbody, thereby reducing aerodynamic drag. The height, shape and position of air-dam must be optimized to get improved drag. Extensive iterations are carried out to finalize the front air-dam size and position until the target is achieved. Researchers used to study the effect of air-dam height, then with fixed height will work to finalize position. Studies with interactive effect of front air-dam height and position are scanty. The existing process is time consuming as the front air-dam size and position is adjusted manually and simulation is being performed for each design and requires detailed analysis for all design iterations. The objective of this study is to couple CFD solver with design optimization software to reduce overall manual design iterations to choose the effective front air-dam geometry. A method is developed to couple CFD solver and optimization tool, with parameters defined as front air-dam size (Minimum and Maximum) and response as drag coefficient. SHERPA algorithm is chosen for this optimization study. Base design CFD aerodynamic drag value is validated with wind tunnel test and the same method is applied for all design iterations. By using this optimization method 1.3% improvement in drag value compared to base design aerodynamic drag value for the considered vehicle geometry and reduction of about 40% manual effort.