2009 Formula One Aerodynamics BMW Sauber F1.09 ... · 2009 Formula One Aerodynamics BMW Sauber...

2009 Formula One Aerodynamics BMW Sauber F1.09 – Fundamentally Different Torbjörn Larsson BMW Sauber F1 Team, Hinwil, Switzerland

ABSTRACT To make Formula One more attractive to a broader audience, radical changes to the FIA technical regulations have been imposed for the 2009 season. Primarily, the lack of overtaking and exciting wheel-to-wheel racing is believed to be a direct consequence of the massive levels of aerodynamics down force generated by modern F1 cars. Therefore, these new regulations are targeting a significant reduction in achievable aero forces via specific restrictions to the shaping of the vehicle exterior. This should also lead to more aero performance retained on cars following in the wake of another car. Claiming back lost aero performance (to good levels) proved to be a true challenge for the aerodynamicists. Reliance exclusively on knowledge and insights gained from intensive engineering of concepts in the past was not going to be adequate to propel this project. New insights were essential, and a comprehensive CFD campaign became instrumental in devising the development path for a fundamentally different race car, BMW Sauber F1.09.

1. BACKGROUND The winds of change are blowing through Formula One. The 2009 season sees arguably the most significant rewrite of the F1 technical rulebook in the history of the sport. New rules governing tires, aerodynamics and Kinetic Energy Recovery Systems (KERS), among others, are considered to be the biggest changes in the Formula One regulations for several decades. Driving forces behind these rule changes are the increasing needs for cost-cutting and improvements to the on-track spectacle.

The aim of the new aerodynamic regulations, as well as the reintroduction of slick tyres, is to decrease reliance on aerodynamic down force and increase mechanical grip with the aim of making wheel-to-wheel racing easier, and hence, promote overtaking. These radical rule changes have literally brought the F1 engineers back to the drawing boards to start from a clean sheet of paper.

EASC 20094th European Automotive Simulation Conference

Munich, Germany6-7 July 2009

Copyright ANSYS, Inc.

Figure 1: The BMW Sauber 2009 (left) vs. 2008 (right) F1 racing cars.

2. AERODYNAMICS DEVELOPMENT PROCESS The development of the BMW Sauber 2009 F1 contender had to centre on the three key areas; tire utilization, aerodynamics and KERS integration. Addressed herein are exclusively the engineering challenges associated with the aerodynamics development of this brand new race car. Here one obvious design approach is to start from what you got, i.e. the existing race car, and convert it into a concept that complies with the new aero regulations. This is an ideal task for the CFD engineers, far more practical than building up any physical models for testing. By doing so, the very first CFD predictions revealed an overall down force reduction by more than 50%! Such a tremendous performance loss is not at all surprising, given that the existing race car is an evolution over many years of engineering and design (with relatively stable rules), whereas the 2009 spec car had to be something more of a revolution to meet the new standards. By nature and definition, revolution is disruptive to people, well-functioning organizations and processes. Hence, achieving revolutionary goals through an evolutionary process would be the desired path to the future. Still, taking such a path requires a process of adequate flexibility to allow for an efficient collection of new knowledge and insights. In this case, relying too much on experiences and know-how from the past might not necessarily bring enough leverage to propel the development forward at a sufficient rate, and it can even (in a worst case) be misleading. Hence, rather than building upon incremental refinements from a given design point, this requires several fundamentally different concepts to be analysed in order to populate a sufficiently broad design space. Computational Fluid Dynamics (CFD) and High Performance Computing (HPC) hold the keys to the success of such a design process.




2.1 CFD Methods and High Performance Computing The Hinwil based race team (before 2005 known as Sauber Petronas) has a long tradition in using CFD for aerodynamics research and development [1-5], and the CFD group has become an integral part of the aero department and its design processes. The launch of Albert3 in 2008, a state-of-the-art Intel based supercomputer tailored for large scale CFD applications, clearly underlines BMW Sauber’s strong belief in, and commitment to, simulation technology. Rather than pursuing a second wind tunnel, the team took this “pioneering approach” with a future more focused around CFD and high performance computing.

Figure 2: BMW Sauber Supercomputer Albert3.

Frequently, BMW Sauber has been referred to as the “benchmark” in F1 regarding HPC and CFD. With a close to 10,000 fold increase in available compute capacity over the last decade, the team today performs simulation scenarios unheard of only a few years ago.

Not only from building up such an outstanding compute facility, but also very much due to the team’s strong commitment to CFD methods development, the overall aero process efficiency has taken a leap forward. Today, using advanced and tailor-made simulation methods, a broad design space can be explored in a relatively short period of time to devise directions for further and more extended research. And before committing to any physical parts production, many design concepts and ideas can be evaluated with good confidence on Albert3.

3. FLOW PHYSICS AND AERODYNAMICS The intricacy of the aerodynamics of a Formula One car is still one of the most fascinating aspects in the engineering of a competitive race car. In particular, the ability to control and stabilize flow patterns emanating from the exposed wheels is of fundamental importance in order to extract the ultimate aerodynamics performance from any open-wheel racing car.




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REFERENCES [1] Akanni S., Larsson T., Bienz C.‚ Numerical Modelling of the Aerodynamic Flow Field about a Formula One Car, Fluent User Group Meeting, Germany 2001. [2] Bienz C., Larsson T., Sato T., Ullbrand B., In Front of the Grid – CFD at SAUBER PETRONAS F1 Leading the Aerodynamic Development, 1st European Automotive CFD Conference, Bingen, Germany, 2003. [3] Kremenetsky M., Larsson T., Numerical Studies on a ccNUMA Computer Architecture for a Large Scale Race Car Aerodynamics Simulation, Parallel Computational Fluid Dynamics 2004, Elsevier Science, ISBN: 978-0-444-52024-1. [4] Larsson T., Sato T., Ullbrand B., Supercomputing in F1 – Unlocking the Power of CFD, 2nd European Automotive CFD Conference, Frankfurt, Germany, 2005. [5] Larsson T., High Performance Computing – Shaping the Future of Formula One, Masterwork Session, 2007 International Supercomputing Conference, Reno, NV, USA.




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