When air flows around a car, it creates pressure differences between the front, sides, roof, and rear. These pressure gradients generate aerodynamic forces. Engineers measure these forces using a balance system mounted beneath the vehicle that calculates drag force, lift, and side forces with high precision. Reducing drag is critical. The aerodynamic drag force is proportional to the drag coefficient (Cd), the frontal area of the vehicle, air density, and the square of velocity. Even small reductions in Cd can significantly improve fuel efficiency or extend electric vehicle range at highway speeds. Wind tunnel testing also reveals complex flow features that are difficult to predict purely through simulation. These include: • Boundary layer behavior along the vehicle surface • Flow separation at sharp edges or the rear of the car • Turbulent wake formation behind the vehicle • Airflow through cooling systems and brake ducts To visualize airflow, engineers often use smoke streams, tu...