A Brief Review on Ground Vehicles Aerodynamics due to the Presence of Streamwise Vortices

Flow past any solid bodies often generates three-dimensional trailing, swirling vortices. Such structures affect the aerodynamic performance of vehicles in motion. The presence of vortices changes the aerodynamic forces that are directly related to fuel consumption, maneuverability, and safety of the vehicles. In this manuscript, a brief review on the presence of three-dimensional vortices and their effects on the aerodynamic performances of the ground vehicles is presented. Specifically, the discussions cover the drag mechanism in passenger cars, heavy trucks, and motorbikes, which is highly affected by the presence of such three-dimensional vortices. Some attempts to reduce drag, both in conceptual prototypes and commercial cars are provided in this paper as well. One of the drag reduction methods, that is, by means of a vortex generator, is often installed in the racing cars and heavy trucks. Qualitative smoke-wire visualization of simple vortex generators on a flat plate is also included in this manuscript.