Towards on-road aerodynamics: Evaluation and implementation of real-world conditions

Abstract

As newer regulations require improved energy efficiency for road vehicles to reduce their environmental impact, the need to study the effect of real-world conditions becomes a strategic step for improving the on-road performance and range of new vehicles. The aerodynamic performance of a road vehicle is sensitive to the turbulence it undergoes in realistic conditions, making the introduction of turbulence to simulations a must. It also provides a better base for an early understanding of a car’s behaviour and optimizations that will perform better in the high turbulence conditions experienced on-road. Adding turbulence levels experienced on the road to aerodynamic simulations will ultimately benefit the end-users, with improved high-speed stability and decreased fuel or energy consumption. The study starts by evaluating literature based on related topics to gather common findings and recommendations. Based on the literature review, the simulations are run with different turbulence settings and further bench-marked to standard quasi-steady simulations in the Computational Fluid Dynamics (CFD) software StarCCM+. Furthermore, coast-down test data is used to extract the aerodynamic load from the total road load using a proprietary method. This serves as a comparison to find what settings are the most representative of realistic conditions. Based on the findings from the comparison between real-world data and in-house simulations, an optimized set of parameters is proposed for a possible standardized method of computing on-road conditions in CFD.