Importance of Sub-Grid Scale Modeling for Accurate Aerodynamic Simulations

Ekman, Petter,1988-Linköpings universitet,Mekanisk värmeteori och strömningslära,Tekniska fakulteten (författare)

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 this study, the flow around the 25 deg Ahmed body has been investigated using large eddy simulations 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. Very good 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 modeling in the standard Smagorinsky-Lilly model, resulting in overpredicted separation.

Venning, JamesDepartment of Mechanical and Aerospace Engineering, Monash University, Victoria, Australia (författare)
Virdung, TorbjörnVolvo Car Corporation Department, Göteborg, Sweden (författare)
Karlsson, Matts,1965-Linköpings universitet,Mekanisk värmeteori och strömningslära,Tekniska fakulteten(Swepub:liu)matka16 (författare)
Linköpings universitetMekanisk värmeteori och strömningslära (creator_code:org_t)

Av författaren/redakt...: Ekman, Petter, 1 ...; Venning, James; Virdung, Torbjör ...; Karlsson, Matts, ...

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