On the Aerodynamic Loading and Deformation of Convertible Car Roofs

Convertible vehicle hoods are known to deform away from their designated showroom shape as a result of aerodynamic loading. The ultimate aim of the work is to produce a computer-based methodology to model the fluid-structure interaction over a convertible vehicle hood. To develop an appropriate flow-structure coupling methodology, steady-state computations have been carried out for a two-dimensional model geometry. A commercial computational fluid dynamics (CFD) package is used to calculate the pressure on the model roof. This CFD package is coupled to an in-house structural code that models the structural mechanics of the flexible roof. Furthermore, a very rapid hybrid means of generating the aerodynamic loading is developed because the multiple solutions required in a complete wall-flow iteration procedure can be computationally very expensive. Solutions generated using the modelling concepts have been compared with wind-tunnel testing on a physical model.