Drag reduction of a commercial bus with add-on aerodynamic devices

Abstract

In the automotive industry, the implementation of drag reduction systems has provided considerable decreases in fuel consumption. These outcomes are in line with the increasing demands of the environmental regulations and consumers’ requirements. Although some studies explain how aerodynamic devices reduce the aerodynamic drag on light and heavy vehicles such as Ahmed bodies and trucks, buses have received almost no attention. For this reason, the flow over the Marcopolo Paradiso 1200 G7 commercial bus and the influence of several aerodynamic devices on the drag force and fuel consumption of the bus are discussed in this article. Three distinct devices (vortex generators, lateral devices, and rails) were proposed after flow visualization tests on the baseline bus. Thus, the entire evaluation consisted of 11 arrangements by combining the three aerodynamic devices. The changes in drag due to all arrangements are estimated using wind tunnel tests, which are validated using Computational Fluid Dynamics simulations. The fuel consumption is evaluated in a simplified long-haul driving cycle between two cities. The devices were able to alter the flow behavior on the bus, resulting in a maximum decrease of 8.63% in the drag coefficient and 3.92% in fuel consumption. Given that the devices used are just first prototypes, we estimate that greater reductions can be achieved with optimized systems. Likewise, this paper probably leads to real applications in other commercial buses due to the evident drag reductions.