Flow field past a generic car body (Ahmed car body) equipped with wheels and wheelhouses was determined by means of RANS (Reynolds averaged Navier-Stokes-equations) modelling. The aim of this investigation was to find the large scale differences in the structure of the flow field due to the presence of wheels and wheelhouses. The interpretation of the 3-dimensional complex flow field was carried out by using iso-surfaces covering regions of low total pressure and high Q values. The low velocity part of the wake region could be captured by iso-surfaces of total pressure, while the dynamically active vortices were found by the iso-surfaces of Q. It was also found that the qualitative structure flow field was very similar to that obtained by the authors of this paper in their former works focusing on the determination of the flow field structure inside wheelhouses of cars. The addition of wheelhouses and rotating wheels led to a dramatic increase both in lift and drag coefficients of the vehicle. The obtained values of the increase of both drag and lift (24% and 42.3%, respectively) were in good agreement with the experimental values published in the corresponding literature for several type (non-generic) cars. The origin of the increase in drag and lift was investigated by integration of pressure and wall shear stress on the individual surfaces, so called sub-parts of the vehicle model to find the components of the forces. It was found that drag increased mainly due to the drag acting on the wheels and wheelhouses, out of which wheels contributed with majority, while lift was increasing mainly due to the overall flow-field modification effect of the wheels past the vehicle model and not due to the lift force acting on them individually.
The effect of wheels on the aerodynamic characteristics of an Ahmed body
Einfluss der Räder auf die aerodynamischen Kennwerte einer Ahmed-Karosserie
2007
11 Seiten, 8 Bilder, 3 Tabellen, 22 Quellen
Aufsatz (Konferenz)
Englisch
The Effect of Wheels on the Aerodynamic Characteristics of an Ahmed Body
British Library Conference Proceedings | 2007
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TIBKAT | 1969
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