Overtaking Aerodynamics Insights- Part 1

At bramble, we’re passionate about “Making hard things easy”. One such example of this is the automation of testing “car following car” models.

If you have ever tried this manually, you’ll know that duplicating and offsetting geometry and boundary conditions can be a time-consuming and error-prone process. With bramble, you can now effortlessly specify the car’s offset (or offsets – we can run multiple cars following each other!). Then let our software handle the intricate details.

Overtaking aerodynamics

To showcase this exciting capability, we’ve decided to explore a fascinating aspect of Formula 1 racing: overtaking aerodynamics. We’ve compared two iconic Ferrari F1 cars – the 1978 312T and the 2016 SF16 – to understand how their aerodynamic performance changes when approaching a lead car.

Our Study Setup:

Both cars simulated at 10m and 20m offsets behind a lead car. In-order to see how aerodynamic performance changes as the following car approaches the lead
Consistent ride heights: 38mm front, 93mm rear. Perhaps a sub-optimal ride height for the SF16, but we wanted to keep some similarity between the two tests.
Speed: 160 kph
Simulation type: Steady-state RANS using a k-omega SST turbulence model.

Let’s start with some numbers…

The graphs below compare the relative downforce (left) and drag (right) levels of both cars with offset distance. These forces are shown as a percentage of their respective “clean air” performance.

overtaking aerodynamics showing graph with downforce of SF16 and 312T with offset distance.

overtaking aerodynamics showing graph with drag of both cars with offset distance

The speed at which an F1 car can take a corner is, in part, governed by the amount of downforce it can produce. The more downforce, the faster it can corner and then the better it can overtake.

From the data above, we can see that the 312T loses around 10% of its downforce at a 20m offset. This increases to 50% at 10m.

The impact on the SF16 is much more pronounced. It loses 52% at 20m increasing to over 71% at 10m. The increased loss in performance of the SF16 compared to the 312T gives some credence to the view that overtaking has got harder in modern F1 cars.

It’s not all about downforce though. In order to achieve high straight-line speeds, drag (or the lack thereof) is king. Whilst the SF16 loses the most downforce, it also experiences a bigger reduction in drag. 40% at 10m compared to 10% for the 312T. Relatively speaking, the SF16 will get a bigger “tow” from the lead-car making it easier to overtake in a straight-line.

So perhaps, overtaking hasn’t got harder in a modern F1 car, it is just harder to do in a corner.

Downforce distribution analysis:

bramble will automatically extract force distributions when a simulation completes. These can be used to compare different models and, for example, can highlight where downforce is gained and lost.

The images below (click on them to enlarge) show the downforce distributions for the 312T (left) and the SF16 (right). Each image contains the distribution for the “clean-air”, 10m-offset and 20m-offset.

aerodynamics of overtaking, downforce distributions for the 312T

Although the 312T loses some downforce from the front wing, particularly at the 10m offset (red line), the majority of the loss comes from the rear wing.

Whilst the SF16 also experiences a loss in downforce from the rear, it also suffers a much more significant loss on the front wing, even at the 20m offset. This additional loss explains why the SF16’s performance is affected much more than the 312T’s.

The world of overtaking aerodynamics:

Our study highlights the intricate balance F1 engineers must strike between maximizing performance in clean air and maintaining effectiveness in turbulent conditions during overtaking. The contrasting behaviors of these two cars from different eras demonstrate how the challenge of overtaking has evolved in Formula 1.

Stay tuned for Part 2 of this series, where we’ll delve deeper into the aerodynamic principles behind the SF16’s front wing performance and explore how modern F1 car designs have adapted to the challenges of overtaking aerodynamics.

At bramble, we’re committed to providing tools that make these complex analyses accessible and efficient for CFD engineers. Whether you’re working on race car aerodynamics or any other fluid dynamics challenge, our software is designed to streamline your workflow and enhance your productivity.

Thanks for reading and watch this space!

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