Drag Optimization of Light Trucks Using Computational Fluid Dynamics

There are 80 million light trucks on the road today with suboptimal aerodynamic forms. Previous research has found that several miles per gallon can be saved by specifically tailoring truck bodies for reduced aerodynamic drag. Even greater savings can be obtained if the shape of the trucks is numerically optimized. This could reduce fuel consumption in the United States by billions of gallons per year.

This paper demonstrates a method for drag reduction using CFD and traditional numerical optimization techniques. A method for efficient design variable reduction for CFD optimization of three-dimensional shapes is also presented and applied to light trucks. The optimized form is then physically constructed and installed on a recent model pickup truck. The vehicle is tested in several configurations and the effects on fuel economy are compared to the CFD prediction.

The results indicate that the CFD formulation provides an accurate predictor for improving fuel economy and drag characteristics. The prototype air dam and optimally shaped canopy generated a 21.23% savings in terms of fuel economy. This corresponded to an improvement in fuel economy from 19 mpg to 23.17 mpg. Ultimately, this research demonstrates a practical example of geometric optimization and validates the results with a full scale test.