Square tub section vs. rounded

[flattyre]

This is probably quite obvious to some of you, but why is it that the tub section of an F1 car has become squarer in recent years?

When you look at cars from the 90s, the tubs were nicely rounded. I would've thought that this made more sense as, as far as I know, sharp edges are a nightmare with turbulence.

What is the justification for the squarer design in more modern cars? Is it to direct more air into the sidepods? To reduce frontal area? Simplification of design (I can't imagine this for one minute)? Or is it something else that I'm overlooing?

[yessamgerg]

My guess is that it a way meet the rules (bulkhead height size etc) with the minimal frontal . It's obviously less strustructurally efficient (think square vs round tube in torsion) but with modern fea and optimization software there are plenty of ways around that. Plus since aero dictates everything chassis stiffness would probably take a back seat to aero anyway

[thisisatest]

i think it's also easier to control/predict where the air is going, in general. square vs round tubes in torsion, depends what your limiting factors are. if youre limited to a max height and a max width, extending the walls to the edge of the box doesnt hurt you, and you make gains in bending. if there is a max cross-sectional width in any direction, the round tube will be superior. if it's with a finite amount of material, the round tube will be superior.

[Richard]

The rules specify minimum bulkhead/nose dimensions in the x and y direction. Hence teams trying to keep the bulkhead as small as possible end up with a rectangular section.

Scarbs has a blog about the bulkhead dims looking at Newey's clever interpretation back in 2010: http://scarbsf1.com/2010/vnoses.html

[variante]

That's right. Also, the rules specify the radii to apply to the survival cell --> http://www.formula1-dictionary.net/Imag ... ension.jpg
Nothing prevents teams from designing a bigger and smoother section around the mandatory one, but that would hardly bring major gains.

Also, CFD programs are largely used today (and have become very accurate), which allow aero engineers to design bodyworks (even sharp ones) without the risk to generate unwanted airflows around the car.

And let's not forget the role of modern bulkheads/noses, which is to channel and accelerate air to the right areas; for this purpose wide and sharp surfaces are required.

Lastly, rounded geometries on the top of the nose do find some applications in todays F1 (in order to reduce drag and NOT to deflect airflow upwards). Just have a look to the Ferrari F14-T nosecone.