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Investigations of the Rear-End Flow Structures on a Sedan Car
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 05, 2016 by SAE International in United States
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The aerodynamic drag, fuel consumption and hence CO2 emissions, of a road vehicle depend strongly on its flow structures and the pressure drag generated. The rear end flow which is an area of complex three-dimensional flow structures, contributes to the wake development and the overall aerodynamic performance of the vehicle.
This paper seeks to provide improved insight into this flow region to better inform future drag reduction strategies. Using experimental and numerical techniques, two vehicle shapes have been studied; a 30% scale model of a Volvo S60 representing a 2003MY vehicle and a full scale 2010MY S60.
First the surface topology of the rear end (rear window and trunk deck) of both configurations is analysed, using paint to visualise the skin friction pattern. By means of critical points, the pattern is characterized and changes are identified studying the location and type of the occurring singularities. The flow field away from the surface is then analysed using PIV measurements and CFD for the scale model and CFD simulations for the full scale vehicle. The flow field is investigated regarding its singular points in cross-planes and the correlation between the patterns for the two geometries is analysed.
Furthermore, it is discussed how the occurring structures can be described in more generalized terms to be able to compare different vehicle geometries regarding their flow field properties.
The results show the extent to which detailed flow structures on similar but distinct vehicles are comparable; as well as providing insight into the complex 3D wake flow.
- Charalampos Kounenis - Durham University
- Sabine Bonitz - Chalmers University of Technology
- Emil Ljungskog - Chalmers University of Technology
- David Sims-Williams - Durham University
- Lennart Lofdahl - Chalmers University of Technology
- Alexander Broniewicz - Volvo Car Corporation
- Lars Larsson - Chalmers University of Technology
- Simone Sebben - Chalmers University of Technology
CitationKounenis, C., Bonitz, S., Ljungskog, E., Sims-Williams, D. et al., "Investigations of the Rear-End Flow Structures on a Sedan Car," SAE Technical Paper 2016-01-1606, 2016, https://doi.org/10.4271/2016-01-1606.
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