Guidelines for SUV Bodywork Design Focused on Aerodynamic Drag Reduction Using the Generic AeroSUV Model 2020-01-0478
SUV Aerodynamics has received increased attention as the stake this segments holds in the automotive market keeps growing year after year, as well as the direct impact it has on fuel economy. Understanding the key physics in order to accomplish both fuel efficient and aesthetic products is paramount, which indeed gave origin to a major initiative to enhance collaborative aerodynamic research across academia and industry, the DrivAer model.
In addition to this sedan-based DrivAer model, a new dedicated SUV generic model, called AeroSUV (Zhang C. T., 2019), has been introduced this year, likewise intended to provide a common framework for aerodynamic research for both experimental and numerical simulation validation.
The present work provides an area of common ground for SUV bodywork design focused on minimization of aerodynamic drag making use of the new AeroSUV model in its three available configurations, namely estate back, fastback and notchback. This allows for maximum representativeness and utilization of results across the industry and academia. Dimensionless parameters are presented in the form of height- to-width ratios and departure angles, looking at an efficient way to characterize vehicle proportions which can lead to aerodynamic efficiency improvements very early in the concept design stage. Although previous work has been performed on this matter not only for sedans (Le Good, 2011) but for some particular SUV models too (Krishnani, 2009), the present paper is intended to establish a first approach for SUV design which incorporates aero efficiency criteria based on its main drag contributors.
Spalart-Allmaras Delayed Detached Eddy Simulations are performed for 6 seconds of physical time, presenting drag coefficient-averages for the last two seconds of the solution as the reported metric to assess the effectiveness of the design parameters investigated. Conclusions are drawn based on a signal-to-noise ratio methodology in order to rank those parameters identified as first order contributors for aero drag and distinguish from those secondary aspects that might have been considered relevant and that CFD results have subsequently proved otherwise.