Ford Fusion in CFD - Photo courtesy Ford RacingEnlarge Photo
Ford Racing is pulling out all the stops to ensure that its 2013 Ford Fusion entries in the NASCAR Sprint Cup Series have been fully optimized. To this effect, Ford Racing is using Computational Fluid Dynamics (CFD) as an engineering tool for aerodynamic loads. "Basically it's a wind tunnel on a computer and we at Ford Racing use it in similar ways that Ford Motor Co. uses it - to make better, more efficient cars," noted Pat DiMarco, NASCAR program manager.
"You can push and pull on different aspects of the car and it's just a matter of somebody's time doing it on the computer," DiMarco added. "You can turn results around overnight, whereas at the wind tunnel, you have to build physical parts, schedule time and then go to the wind tunnel. That gets very expensive so once the upfront investment is made, CFD is really an efficient way of doing things."
Ford has an 18-month window to design, build and test its newest Sprint Cup Series challenger, making methods like CFD an integral part of the process. Ford Racing is working in conjunction with the Ford Motor Co. design center and its own aerodynamicists to best define the slippery properties of the new Fusion.
Ray Leto - Anne Proffit photoEnlarge Photo
Ford Racing is using CFD manager Ray Leto, an experienced Indy car engineer who is fluent in CFD dynamics, together with technical expert Naethan Eagles and engineer Ted Pandaleon, to make certain the 2013 NASCAR Fusion is right before a single hand is placed on an actual piece of sheetmetal.
"We think the big benefit of merging the numerical simulation with the physical testing is that you can do some quick iterations in the numerical world that you wouldn't be able to do in the physical world, whether it's a scale-model or the full-scale car" Leto explained. "We can try lots of different things, whether it's just subtle design changes in small areas of the car or big concept changes. We basically do the same thing as the physical wind tunnel, just in a numerical simulation."
Aside from being able to quickly make a series changes to a car using CFD, it shows aerodynamic strengths and weaknesses of the Fusion from a different group of perspectives. "One of the best things about CFD is that we can see the flow of air over the car," said Pandaleon. "We can see the pressure on the surfaces very easily, so we have an idea of what's going on. We're able to pinpoint and focus our development to areas we know are going to get good results."
Because NASCAR is looking toward more brand identity in its Sprint Cup cars in 2013, the manner of designing these race cars had to be altered. The group had to balance optimal numbers for downforce, drag and side-force without sacrificing the sleekness of the all-new Fusion production car.
CFD helps Ford Racing optimize the NASCAR Fusion - Photo courtesy Ford RacingEnlarge Photo
Eagles would "take the cue from the stylist and then push past where he wanted to go and find out what we could do performance-wise," he recalled, "and then figure out the best way to pull back to what was needed from a styling perspective and what was acceptable from the downforce perspective. I think the car evolved quite a lot over time, as we went around different parts of the car, trying to manipulate the surfaces to deliver the required performance while still hitting the styling cues."
"CFD really helped us focus on issues we had along the way," DiMarco stated. "We had our standard process that we use with scale-model and then full-scale testing, but when we hit some bumps on the road, we were able to go find a little bit more of this or a little more of that, and we were able to do it very efficiently and very quickly."