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Methodology Results and discussion
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Methodology Results and discussion
For all the cases, the pressure coefficients in front of the bumper and
00the windscreen were positive, but that associated to the roof was always
00negative.
there are more positive pressure coefficients on the upper wing of the
00spoiler for case 4 than other cases as shown in Fig. 5d.
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Methodology Results and discussion
Fig. 6 shows the comparison of the drag and
00lift coefficients for the six cases studied.
it is important to point out that only the
00spoiler for case 4 produced a negative lift
00coefficient. This implies that, among the
00design considered, the spoiler design
00number 4 produces the greatest vertical
00stability but that without a spoiler yields the
00worst.
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Methodology Results and discussion
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Methodology Results and discussion
The vorticity distributions for these cases are
presented in Fig. 8.
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Methodology Results and discussion
For each of the case studied, four
monitoring points were put in the
computational domain at different
locations to record the pressure
parameter.
These positions are shown in Fig. 9 and
their coordinates are listed in Table 3.
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Methodology Results and discussion
Fig. 10 compares the sound pressure levels at those four record points
00shown in Fig. 9
it is found that the installation of a spoiler structure may increase or
00reduce the sound pressure level. With an inappropriate spoiler design
00(cases 5 and 6), the sound pressure level may increase as much as
0020%. An appropriate design can subdue the production of sound
00pressure level by roughly 10% and also lower the lift coefficient.
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4. Summary
1.
2.
3.
4.
Computational fluid dynamics (CFD) simulations of the transient flow
field around a 2D cylinder and six vehicle models with different spoiler
designs were presented and compared to relevant experimental data
reported in the literature .
Based on the cases considered in this work, the installation of a spoiler
reduces the lift coefficient that leads to better conditions for high speed
driving and improves the vertical stability of driving.
The lift coefficient of case 4, which is approximately -0.001, is the lowest
among all the cases studied. This indicates that the spoiler design of of
disordered flow. case 4 has the best vertical stability.
The spoiler configuration in case 4 represents the best design as far as the
aerodynamics and aero-acoustics are concerned.
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