An Assessment of Detached-Eddy Simulations of Unsteady Crosswind Aerodynamics of Road Vehicles

In this paper, the availability of Detached-Eddy Simulations (DES) for simulating unsteady crosswind aerodynamics in industrial applications is explored and reported. The flow around a simple car geometry under headwind, steady crosswind and time-dependent wind gust respectively, is analysed for two different types of mesh using a commercial software, STAR-CD. The typical Reynolds number of the flow cases studied is 2.0 · 10⁶ based on the vehicle length. The performances of polyhedral meshes together with a comparable hexahedral mesh are evaluated for capturing the time development of the flow structures during a gust. From the results presented, it can be concluded that the aerodynamic coefficients can be reliably calculated using both polyhedral and hexahedral meshes, although the fine turbulent structures in the wake are better captured with the hexahedral mesh. Using turbulence methods like DES in order to resolve the flow scales provides a significant insight for designing a ground vehicle and, due to the reasonable computational times involved, can hence be foreseen to be incorporated in a design process in a near future.