In Formula One, the drive for performance is relentless. Under the current technical regulations, aerodynamics is the key area where crucial lap time gains can be made. Traditionally aerodynamic development has been conducted in wind tunnels, however thanks to the recent exponential growth in computing capacity, CFD has rapidly become an essential design tool for the top teams.
So what exactly is CFD? CFD, or Computational Fluid Dynamics, is commonly described as ‘a wind tunnel in a computer’. Using enormous computing capacity and sophisticated software, it allows engineers to simulate and analyse the aerodynamic properties of a part before it is manufactured.
The starting point for a CFD simulation is a CAD model (1) of the car which is subsequently subdivided into many triangles, some as small as a few square millimetres, to create a surface mesh (2). Once the geometry of the entire car has been broken into millions of small elements, a similar process is followed for the air surrounding the car to create a volume mesh. When this mesh is complete, the resulting model is loaded onto a super computer (3) where a very sophisticated piece of software, the CFD solver, then computes the Navier-Stokes equations (4) to calculate the airflow around the vehicle to an astonishing degree of accuracy. This can produce up to 1 billion numbers for computer interpretation (5).
From this CFD solution, engineers can extract a tremendous amount of information. This include fundamentals such as the aerodynamic forces acting on the car (lift, drag, balance), as well as stunning visual graphics that represent the precise nature of the airflow over the various surfaces of the vehicle. The ability to visualise the flow is a particularly powerful tool as it helps the engineers to understand the aerodynamics of the car in a way which would not be possible using wind tunnels alone. Contour maps of surface pressure are studied, air streamlines are traced and velocity maps around the vehicle are analysed in a bid to improve the aerodynamic efficiency of the race car.