Wind-Tunnel Study of the Traffic-Wake Impacts for Road-Vehicle Aerodynamics

2026-01-0613

4/7/2026

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When driving in traffic, the wakes of leading vehicles reduce the wind speed experienced by a following vehicle, lowering its drag relative to isolated driving. These wake effects can persist to large inter-vehicle distances, on the order of hundreds of meters, while lateral convection due to cross winds can influence vehicles in adjacent lanes. Wind tunnel testing was conducted at 30% scale for light- and heavy-duty-vehicle models in a large wind tunnel with a traffic-wake simulation system, expanding upon a previous study that examined only heavy vehicles. Three variants of the DrivAer model, four variants of the AeroSUV model, and three variants of a zero-emission heavy-duty-truck model were tested with a range of simulated wake conditions that varied the type, forward distance, and lane position of the wake-source vehicle(s), for a range of yaw angles up to 11°. Results show drag reductions of up to about 10% for the heavy-duty-truck model, and up to about 20% for the passenger-vehicle models. Surface-pressure measurements provide insights about the sources of drag reduction in wake effects, highlighting the balance between strongly-varying forward-surface pressure differences and mild base-pressure increases.
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Citation
McAuliffe, B., Ghorbanishohrat, F., and Barber, H., "Wind-Tunnel Study of the Traffic-Wake Impacts for Road-Vehicle Aerodynamics," WCX SAE World Congress Experience, Detroit, Michigan, United States, April 14, 2026, https://doi.org/10.4271/2026-01-0613.
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Publisher
Published
Apr 07
Product Code
2026-01-0613
Content Type
Technical Paper
Language
English