One of the biggest areas of endeavour in motorsport is improving aerodynamics, which is also key to success in many other industries. Tom Shelley reports
Advances in aerodynamics, driven by increasingly intense competition and expenditure in Formula 1, could deliver substantial payback for designers in areas such as production car design and rotating machinery.
Toyota Motorsport is a high-profile name that is committed to driving improvements, as Mark Gillian, the company’s head of aerodynamics, explains: “The biggest issue we have is the rotating tyre. The wakes are very complex structures. The flow is quite unsteady. We are driving the CFD vendor [Star Adapco] hard to improve correlation [with the real world]. We spend quite a lot on future development, some with research institutes and some with universities.”
Toyota is not one of the teams at the front of the F1 grid – it has yet to win a race – but boasts an aerodynamics team that numbers more than 100, with some 30 designers, 30 aerodynamicists and 30 model makers. And while it may not be taking the chequered flag right now, it is part of a company that has become the undisputed leader when it comes to building production cars. Unlike most of the F1 teams, Toyota Motorsport has a very close relationship with the manufacture of these vehicles.
“We have very close links with Toyota Motor Corporation [TMC],” Gillian points out. “People come here for three-year periods to learn techniques that can then be applied to production cars. We also have weekly meetings with TMC. It is not just the technologies, but also the techniques.” Gillian singles out the kinetic energy storage systems – which will be mandatory on F1 cars in 2009 – as an example. So while Toyota may not be winning F1 races, it is winning the race that matters: to be the number one car manufacturer in the world. And that clearly influences what is happening at its state-of-the-art centre in Cologne, close to the heartland of the German motor industry.
In particular, drivers of Toyota cars and SUVs may have noticed that the poor handling in cross winds has improved dramatically of late, while the old complaint that Toyotas were very reliable, but boring to drive, seems to have been consigned to history.
Aerodynamics and CFD are clearly regarded as crucial, to the extent that the F1 team considers it worth moving to wind tunnel-testing 60%, instead of 50%, scale models. The aerodynamics department is divided into teams, each of which focuses on a particular area, such as front wings, bodywork, suspension or next year’s car. The computer used is a very big cluster, says Gillian, involving a great deal of rapid prototyped components. Detail in a 60% model is apparently much greater. However, going bigger still would mean putting a huge load on components.
When Eureka visited the site, there was a complete car in the wind tunnel.
“We do tests from time to time on a full-scale car to verify our models,” Gillian explains.
PIV - Particle Image Velocimetry – is used, whereby the airflow is seeded with particles whose movement is observed, using flashes of laser light. Thanks to its computing power and CFD skills, Toyota is now finding that the real-world measurements reproduce the computer models extremely closely.
“We only look for a correlation with standard conditions”, he says.
However, having verified their CFD models, they can then use CFD to analyse non-standard conditions, confident that the basis of the models has been verified correct.
Much of the modelling is concerned with cornering. “Most of the aerodynamics work is done at the track, at 200kph, which is an average speed for cornering,” states Gillian.
Apparently, the FIA limits the teams to only 12 days per year for pure aerodynamics testing, which they normally carry out on airfield runways. For additional studies, he says, almost all teams will run their wind tunnels and belts at 200 to 220 kph.
As regards design responsiveness, he comments: “I used to work in aerospace where we had 12 to 20 years’ lead time. Here, we can design, build and test in a day.”
A normal lead time for a front wing is six weeks, but, as he explains, it can be significantly shorter. “For next year, our releases are scheduled.” This is because they produce specific aerodynamic packages for particular circuits, including special ones for circuits such as Monaco – which is slow speed, with tight corners and walls on each side –- and Monza, which is particularly fast. Not surprisingly, in light of this, “the aerodynamics department is now the size of the whole Formula 1 team a few years ago”.
The wind tunnel models, too, have become highly sophisticated, with fully active ride height control and the ability to steer the car, both of which have to be controlled remotely.
Even more work is anticipated for the season after next when the biggest changes in F1 are set to be introduced, including the kinetic energy storage system and large-scale aerodynamic amendments, which have the potential to halve the down force. “It is up to me to make sure they don’t!” comments Gillian. “The front wings have grown for 2009 and the rear wing has shrunk,” he says, while, in today’s cars, “down force is incredible. If you could find a driver mad enough to do it, the cars would fly upside down”.
Design and FEA are also significant at Toyota Motorsport. The team has 160 seats of Catia V5 R16 SP7, from Dassault Systemes, with 120 used by designers and 40 by others for viewing. For FEA, it uses Abaqus. This is important, not only to design parts so they have minimum weight, yet do not break, but also because the regulations require that the various wings be very stiff and not bend. So much so, says Gillian, you could stand on the front wings, which typically change in design five or six times in a season. And that is even more challenging and demanding than it sounds.
“As soon as you make a change at the front wing, you have to change things all the way down the car,” he says.
Pointers
* The sophistication and effort of CFD modelling and wind tunnel verification have improved dramatically
* They are also being applied to the improvement of production cars and have the potential to be applied elsewhere
* Real-world measurement is now found to reproduce computer models extremely closely
Model behaviour
Toyota Motor Corporation has agreed a multi-year contract with Maplesoft, a leading provider of high-performance software tools for engineering, science and mathematics.
The partnership will produce advanced physical modelling tools to help Toyota move to a new product development process called the ‘Model-Based Development’ (MBD). Key features of the process include control system design and physical (‘plant’) modelling, based on a symbolic approach.
Toyota has embraced model-based design, the concept of creating a computer-based model of a system to analyse, test, improve and optimise the design before building the physical system. In the initial stages, this was used in the design, simulation and implementation of control systems. Toyota is now expanding its scope with the development of MBD.
The goal of MBD is to improve time-to-market, quality and reliability, while reducing cost. Physical modelling requires a symbolic approach to computations in order to represent real-world physical systems accurately and efficiently. Toyota has recognised Maple – an advanced software tool from Maplesoft – as an important part of this framework, providing the ideal mathematical environment for physics-based modelling.
Maple uses a powerful computation engine to derive and solve complex sets of equations, simplify large sets of equations, develop advanced mathematical models and create user-friendly technical applications.
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