The Aerodynamic Influence of Rim Design on a Sports Car and its Interaction with the wing and Diffuser Flow
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Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Automotive engineering (MPAUT), MSc
Publicerad
2010
Författare
Cederlund, Johan
Vikström, Jakob
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Global climate change and increasing fuel prices demand more efficient vehicles. Today the automotive industry invests significantly into developing more efficient engines and to reduce the required force to propel the vehicles. For a passenger car the aerodynamic drag is a dominant part of the total resistance at highway speeds. In the area of sportscars, aerodynamic drag is even more dominant due to higher speeds and the fact that aerodynamics is also used in order to increase downforce. This result in contradictory demands as downforce often comes with a drag penalty. There has to be a delicate balance between the two. Even though the fuel price is not an issue when racing, there is a demand for efficient vehicles in order to obtain as much performance as possible within the rules. The wheels have been shown to have a large influence on the global aerodynamic properties of a vehicle. It has also been shown that the local flow field around the wheels and wheel housings is highly dependent of the rim design. In this project the influence on the global as well as the local aerodynamic properties from the rim design was studied. In addition the interaction between rim design and diffuser was investigated as well as the interaction between the diffuser and the wing. The simulations showed clearly that a substantial decrease in drag can be achieved with proper rim design. Blocking the crossflow through the rims result in increased static pressure in the front wheel house and thereby an increase in lift, whereas blocking the crossflow in the rear result in increased downforce due to an increased flow rate through the diffuser. It was however shown that the resulting flow around the rear wheel was highly dependent of the rim design in the front. Furthermore it was shown that removing the lower wing increase the downforce generated from the upper wing whilst the base wake aft of the vehicle was substantially reduced and thus also the driving force for the diffuser leaving it less efficient.
Beskrivning
Ämne/nyckelord
Energi , Transport , Hållbar utveckling , Innovation och entreprenörskap (nyttiggörande) , Teknisk mekanik , Energy , Transport , Sustainable Development , Innovation & Entrepreneurship , Applied Mechanics