Bahrain, what is the flow viz used by Red Bull and McLaren. And why Ferrari hasn't adopted it

The first day of testing is always the one in which the teams must most understand the dynamic behavior of the single-seaters and verify the correlation between the simulation data and that collected on the track regarding aerodynamics. For this reason, especially at the start of the session, practically all the teams have instrumented their respective single-seaters, equipping them with "rakes" of sensors to measure the pressure of the air flow in certain specific positions. In addition, the use of "flow viz" has also been widespread, a fluorescent paraffin-based liquid that, when brushed on specific areas of the cars, provides technicians with visual feedback on the behavior of the air flow that laps the car. In essence, the creation of actual flow lines through the formation of fluorescent streaks along the bodywork allows us to know at which points the flow is laminar, i.e. straight and non-turbulent, and where any detachment occurs.

Usually teams adopt this method to verify the effects of a specific modification at the aerodynamic level, even at the level of a structural element of the design. For example, a different position of the suspension arms influences all the aerodynamics in the areas immediately behind and surrounding that element. Among the top teams, Red Bull and McLaren were the ones who made the most extensive use of flow viz. Respectively on the RB21 the investigation concerned the front end with the side of the body immediately behind the front suspension covered in fluorescent yellow liquid. On the MCL39, however, the technicians analyzed the flow pattern that hits the rear wing, to evaluate the influence that the cooling system vents, clearly inspired by Ferrari, had on the main profile of the wing.

A curiosity that seems worthy of note, then, is the fact that Ferrari was the only team not to use the flow viz to check the progress of the fluid threads. This is partly surprising, if you think that the adoption of the new pull rod suspension at the front has a strong influence on the air flows directed towards the sides and the leading edge of the floor. It could be a not irrelevant clue, that the technicians from Maranello immediately found the expected correlation between the virtual data and those collected with the "rakes", at the beginning of the morning. Something that, if confirmed, would indicate that the tools available to the engineers directed by Loic Serra are precise and reliable. In any case, it is correct to reiterate that it is impossible to draw precise conclusions after only the first day of testing in Sakhir.