Drag reduction technology and devices for road vehicles - A comprehensive review

This paper addresses the critical role of drag reduction technology in the evolution of road vehicle design amidst the ongoing climate crisis. With transportation accounting for a substantial portion of the EU's greenhouse gas emissions, the shift towards alternatively powered vehicles highlights the need for innovative solutions to extend range, reduce fuel consumption, and lower emissions. This review thoroughly outlines the literature on appendable drag reduction devices, encompassing both passive and active techniques, and their applicability across a variety of road vehicles, including light and heavy-duty transport. Methods applied to simplified bodies such as the Ahmed or other commonly studied generic bluff bodies are clearly distinguished from those applied to more detailed road vehicles, where results hold greater practical significance due to authentic geometry. A combination of both wind tunnel and CFD works are outlined with insights given into how advancements in both computing power and CFD will greatly enhance the future outputs of drag reduction research for road vehicles. Finally, an outlook is provided on the future of the technology and how increased consumer demand for configurable vehicles will encourage increased engagement between drag reduction device manufacturers and automakers to improve the device mounting process.