Swapping out modern methods for more traditional ones can sometimes raise eyebrows, as was the case when Alpine deployed a classic technique during their aero testing at the recent Italian Grand Prix. In lieu of the ubiquitous flow-vis used to examine aero part effectiveness, a method characterized by its colorful paints, Alpine introduced yarn tufts to probe a newly revised low downforce Monza-specific beam wing.
Interestingly, the yarn tuft technique was considered outdated, as Formula 1‘s grasp on airflow comprehension and technology has skyrocketed over the years. However, this deviation to an older procedure was not without cause. It all springs back to the kind of aerodynamic understanding teams aim to derive from practice runs.
Typically, flow-vis— a mixture of fluorescent powder and light oil— is applied liberally on a selected part of the car. When the vehicle is taken for a spin, the flow-vis is carried along by the airflow, eventually spreading over the car leaving an evident trail of flow structures. This even highlights areas where separation might have occurred. Upon the car’s return to the pit, teams capture images of how the flow-vis has behaved. This provides an opportunity for aerodynamicists to analyze whether the parts functioned as expected. However, this is all post-event analysis.
Flow-vis, despite revealing the aftermath of aerodynamics, fails to provide real-time evidence of how they are functioning at a specified location on the track or a selected speed. This is where Alpine‘s use of tuft testing shines.
Using high-resolution cameras that are specifically tuned to focus on the tufts, they record footage of how individual strands interact when the vehicle is running. These strands, by indicating their airflow direction and pressure fluctuations, highlight potential stall issues which are later compared at a range of speeds and different corners. This allows for a deeper understanding of tuft behavior at every moment on the circuit – a distinct advantage tuft testing holds over flow-vis.
To select between classic tufts or current flow-vis boils down to a straightforward choice for teams. They must decide whether they want to know what the airflow is doing in the moment, or what has happened post-event.