Flow structure characteristics of the simplified compact car exposed to crosswind effects using CFD

Abstract

Aerodynamic characteristics of a car are important in reducing car accidents caused by wind loading and in lowering fuel economy, continuing to be a major topic of interest. The restrictions of wind tunnel tests and the rising trend of numerical methods have been complied with by past researchers to investigate vehicle aerodynamics computationally. This research aims to analyze comprehensively the effect of crosswinds on a moving vehicle in terms of aerodynamic loadings and flow structures using commercial fluid dynamic software ANSYS FLUENT. This paper will focus on the CFD-based simplified compact car body developed in CATIA V5 by neglecting the external parts such as side mirrors and underbody. The implementation of Standard k − Ɛ model with the inlet velocity, v is setup to 30.56 m/s and Reynolds number equal to 8.89 × 105 by using numerical analysis for this research. The generic compact car which represents car geometries are expected to influence the aerodynamic characteristics whereas the crosswind angles are increased, it will cause high values for the coefficient of side forces and rolling moments in terms of aerodynamic loads due to the existence of the vortices at the leeward region. At Ψ = 0°, the coefficient of side force (Cs) is close to zero and this is predicted because the flow to the body is aligned to the inlet velocity, v.