Bargeboard (aerodynamics)

Bargeboards are pieces of bodywork on open-wheel racing cars, serving a purely aerodynamic (as opposed to structural) function.

The upper, downward sloping edge can shed a large vortex downstream around the sidepods, where it can interact favorably with flip-ups, or aid in sealing the low pressure underbody flow from the ambient stream.

The bottom edge of the bargeboard can also shed vortices that energize the airflow to the underbody, which can help delay flow separation and allow the use of more aggressive diffuser profiles.

In recent years, these two edges have acquired relatively large serrations or protruding tabs to enhance this aspect of their performance.

Initially relatively simple in their design, bargeboards and turning vanes became progressively more complex through the 2000s, integrating with the floor, mirror supports, suspension mounts, and other structures in more elaborate ways.