Comparison Between the Conventional Body-Fitted and the Lattice Boltzmann CFD Methods for the Flow around a Generic Pickup Truck

Computational Fluid Dynamics (CFD) has gained popularity as a tool for many airflow situations including road vehicle aerodynamics. This trend, to bring CFD to bear on vehicle aerodynamic design issues, is appropriate and timely in view of the increasing competitive and regulative pressures being faced by the automotive industry. For a large portion of the engineering community, the primary source of CFD capabilities is through the purchase of commercial CFD codes. This paper summarizes the results of a series of benchmark external aerodynamic simulations that were carried out for a generic pickup truck model using two commercial CFD codes, namely Fluent and the PowerFLOW. For direct comparisons the computations and the experiments were performed for the same model (vehicle) geometry and under similar flow conditions.

The comparisons between time-averaged measurements and computations revealed that the CFD calculations were able to track the flow trends well, however, the ability of the codes to accurately predict the absolute values were limited. Also, the comparison the CFD results suggest that there is no significant differences between the two CFD codes in terms of predicting the flow characteristics for the problem considered in this study. The accuracy of predicting the drag coefficient for the pickup truck model is within 14%.