Abstract
Keywords: Car aerodynamics, car-truck overtaking process, unsteady flow, drag forces, Computational Fluid Dynamics, turbulence modelling
Numerical computations of an overtaking process approximated by fixing a truck model at characteristic stationary positions relative to a car model were performed. The reference database (geometry, operating parameters and surface pressure distribution) are adopted from an experimental investigation carried out in the wind tunnel of the BMW Group in Munich (Schreffl, 2008). Prior to the truck-car interaction during the overtaking maneuver the aerodynamics of the isolated car without the truck has been experimentally investigated to establish the reference pressure distribution for subsequent tests. The present computational study focuses on validation of some recently developed turbulence models for unsteady flow computations in conjunction with the universal wall treatment in such complex flow situations. The computational analysis includes both the isolated car and truck configurations in addition to their most critical relative position during the overtaking process corresponding to the largest drag coefficient.