Two tools, one goal
Every aerodynamic surface on a Formula 1 car is designed using two complementary tools: the wind tunnel and computational fluid dynamics (CFD). The wind tunnel is a physical facility where scale models of the car are tested in real airflow. CFD is a digital simulation that models airflow using supercomputers.
Neither tool is perfect on its own. The wind tunnel gives real-world data but is limited by regulations on how much time teams can spend in it. CFD is unlimited in theory but can miss subtle real-world effects that only appear when air meets a physical surface.
How the wind tunnel works
F1 teams use 60% scale models of their cars, blown by fans that can generate wind speeds of over 150 mph. The model is instrumented with hundreds of sensors that measure downforce, drag, and airflow patterns. Engineers test hundreds of configurations — different wing angles, floor geometries, and bodywork shapes — to find the optimal setup.
But the FIA limits wind tunnel usage. Teams are allowed a certain number of runs per week, and the amount of time is tied to their championship position. The team that finished last in the constructors' standings gets more wind tunnel time than the team that finished first. This is designed to help struggling teams catch up.
How CFD works
CFD uses supercomputers to solve the equations of fluid dynamics around a digital model of the car. It can test thousands of configurations in the time it takes a wind tunnel to test dozens. It is also cheaper — no physical model needs to be built, and no facility needs to be operated.
But CFD is only as good as the mathematical models it uses. The turbulence models that simulate real-world airflow are approximations, and they can miss subtle effects like the interaction between tire wake and floor airflow. That is why teams always validate CFD predictions in the wind tunnel before putting a new part on the car.
Why correlation decides championships
The team that gets the best correlation between CFD, wind tunnel, and reality is the team that produces the fastest car. If a team's CFD predicts a certain amount of downforce but the wind tunnel shows less, there is a correlation gap that must be closed. If the wind tunnel shows one thing but the car on track does another, the gap is even bigger.
Mercedes' dominance in the hybrid era was built on exceptional correlation. Red Bull's success in the ground-effect era came from understanding floor aerodynamics better than anyone else. In 2026, with new cars and new aero rules, the correlation race starts from zero again.