Aerodynamic Effect on Vehicle Handling

<div class="section abstract"><div class="htmlview paragraph">Vehicle handling is significantly influenced by aerodynamic forces, which alter the normal load distribution across all four wheels, affecting vehicle stability. These forces, including lift, drag, and side forces, cause complex weight transfers and vary non-linearly with vehicle apparent velocity and orientation relative to wind direction. In this study, we simulate the vehicle traveling on a circular path with constant steering input, calculate the normal load on each tire using a weight transfer formula, calculate the effect of lift force on the vehicle on the front and rear, and calculate the vehicle dynamic relation at steady state because the frequency of change due to aerodynamic load is significantly less than that of the yaw rate response. The wind velocity vector is constant while the vehicle drives in a circle, so the apparent wind velocity relative to the car is cyclical. Our approach focuses on the interaction between two fundamental non-linearity’s: the nonlinear aerodynamic forces and the nonlinear relationship between tire lateral force, attack angles, and normal loads. Real-time calculation of the understeer coefficient is performed as the vehicle traverses the circular path. We then compared how yaw rate, tire slip angles, and understeer changed for different types of cars (neutral, understeer, and oversteer) at various car and wind speeds. The understeer car showed high variation as at certain speeds the vehicle switched from understeer to slight oversteer due to loss of traction at rear tires.</div></div>