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Abstract

The Ahmed body is one of the most well-investigated vehicle bodies for aerodynamic purposes. Despite its simple geometry, the flow around the body, especially at the rear, is very complex as it is dominated by a large wake with strong interaction between vortical structures. In the present study, the flow around the 25° Ahmed body has been investigated using Large Eddy Simulations (LES) and compared to high-resolution particle image velocimetry (PIV) measurements. Special emphasis was put on studying three commonly used Sub-Grid Scale (SGS) models and their ability to capture vortical structures around the Ahmed body. The ability of the SGS models to capture the near-wall behavior and small-scale dissipation is crucial for capturing the correct flow field. Excellent agreement between simulations and PIV measurements were seen when using the dynamic Smagorinsky-Lilly and the Wall-Adopting Local Eddy-Viscosity SGS models, respectively. However, the standard Smagorinsky-Lilly model was not able to capture the flow patterns when compared to the PIV measurements due to shortcomings in the near-wall modelling in the standard Smagorinsky-Lilly model, resulting in overpredicted separation.

Item Type:	Article
Authors/Creators:	Ekman, P and Venning, J and Virdung, T and Karlsson, M
Keywords:	vehicle aerodynamics, computational fluid dynamics
Journal or Publication Title:	Journal of Fluids Engineering
Publisher:	Asme-Amer Soc Mechanical Eng
ISSN:	0098-2202
DOI / ID Number:	https://doi.org/10.1115/1.4048351
Copyright Information:	Copyright 2021 ASME
Related URLs:	Google Scholar: Venning, J UTAS Profile: Venning, J
Item Statistics:	View statistics for this item

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