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Car manufacturers have a growing interest in developing more efficient vehicles. New technologies have emerged in different areas one of them is vehicle aerodynamics. The aerodynamic resistance, i.e., the forces generated by the air in a vehicle, has considerable influence on fuel consumption. In this paper it´s presented a computational methodology using CFD (Computational Fluid Dynamics) and optimization tool to evaluate production vehicle and indicate possible ways to reduce its drag coefficient. Efforts are concentrated on modifying the geometry of the external design, a procedure whereby vehicle´s regions of interest are chosen to be valued on a pre-set geometric range parameters, arranging a DOE (Design of Experiments) that are evaluated virtually. In a fully automated procedure, changes are made to these parameters using morphing tools and then CFD calculations are performed. Software ANSA and Star-CCM + are respectively used.

It is known that aerodynamics influences directly on a vehicle´s fuel consumption, especially at speeds above 45-60km/h, where it becomes the main parasitic loss. With increasing pressure on automakers to develop more efficient vehicles, aerodynamics is playing a crucial role in the goal of saving vehicle´s fuel. Usually aerodynamic development starts in the early stages of the project, responsible engineer works together with designers and body/ergonomics engineers, using CFD simulations as tool. At certain point in the development time line, full scale or scaled models are manufactured and tested in wind tunnels, where vehicle gets a refinement on its external aerodynamics. However, the measurement of aerodynamic drag which is effectively used for homologated vehicle´s fuel consumption is done by coastdown testing. This paper shows a correlation between results from CFD simulations and results measured from wind tunnel and coastdown testing.