CFD study of aerodynamic sensitivity to air deviation angle for a hatchback vehicle

Abstract

Abstract Movement is the base of most nowadays activities. For this purpose, vehicles that have specific characteristics for various needs were developed. The current legislation enforces an aerodynamic homologation process to assess a vehicle’s CO2 footprint. This process has to be done in specific conditions, with airflow at 0 degree deviation. The increasing concerns toward pollution will soon lead to the introduction of new rules meant to closely simulate real life vehicle usage, like the RDE test. The current paper has the purpose to analyse, using the CFD method, the influence of the directionality of the airflow (i.e. front-at 0 degree deviation and at various deviation angles) on the aerodynamic performance of a vehicle. The paper studies the airflow behaviour of a hatchback body type vehicle for airflow direction angles between 0 and 20 degrees, through Cd parameter. The focus of the analysis was on air direction (± angles) and simulating time. Due to vehicle asymmetry, the results were different in case of positive and negative values of the airflow angle. The simulation time leads to slightly different Cd due to different averaging periods. Obtained results indicate the necessity of future investigations towards the optimisation of aerodynamic elements in crosswind conditions.