الفهرس 
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Abstract
The thesis is dedicated to investigate the dynamic effect of wheel rotation on the
aerodynamic coefficients of dry and wet-condition wheels of Formula One racing
cars. The study includes the evaluation of the tread design of wet-condition wheel as
a parametric study. A CFD approach was used to investigate the forces acting on the
wheel. This was performed using the Ansys Fluent CFD package. In spite of the
high level of confidence in the Ansys simulation package, a validation work should
be done. In this validation work, the coefficient of pressure on the dry wheel
circumference at middle plane was selected as an experimental data from literatures.
A comparison between the computed results and the experimental ones have been
accomplished and showed good agreement. Another computational model of
Formula One racing car rotating wet-condition wheel in contact with the ground is
studied as the main case study. The validation work supported the main case study
by defining the most reliable conditions of testing such as the optimal mesh method
and size, the computational domain size, and the best turbulence model.
The wet-condition wheel case was modeled using Rotating Reference Frame in
order to simulate the dynamic effect of its rotation. The value of resistive torque was
computed for each wheel model (dry and wet-condition). Also, a parametric study
on the tread design of the wet-condition wheel was performed by varying the tread
depth (h) and the pitch angle (θp) of the tread elements. In addition, general
schematic pictures of the flow behavior around the wet-condition wheel are
presented. The main conclusions reached in this study are summarized into three
main points:
Ansys Fluent can be used to produce realistic results using the dynamic analysis of
the flow around dry rotating wheel in contact with a moving ground. In general, it
shows good agreement to the experimental work in the verification case study. In
addition, in the case of rotating wet-condition wheels in contact with a moving
ground, it shows reasonable outcomes related to flow physics. The realizable k-ε option is a good approach in capturing the flow physics and features near the wheel
surface such as the turbulent boundary layer and the flow separation. However, the
model could not predict the spike and the DROP in the Cp values in the validation
case.
The values of the resistive torque are high especially in the wet-condition wheel
model. Consequently, the aerodynamic resistive torque has a relatively high effect
on the wheel performance and is a new parameter which has to be considered. The
moment coefficient of the wet wheel reaches a value of -0.085 at tread depth of 6
mm and 8 deg of pitch angle. The effect of decreasing the tread depth can
significantly decrease the moment coefficient to reach a value of -0.05 at a tread
depth of 2 mm. The decrease in tread depth does not show a noticed change in the
drag and lift coefficients. The decrease in the tread pitch angle decreases the
moment coefficient to reach a value of – 0.045 at 5.5 deg of pitch angle. On the
other hand, the decrease in the pitch angle slightly lowers the drag coefficient. This
difference in drag coefficient comes with a penalty of increasing the lift coefficient
by the double of its value.
The new parameters which have no corresponding experimental results, such as
tread design parameters, were only computationally evaluated. These parameters are
stated as interesting points for the future work in the recommendations in order to be
evaluated experimentally.