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DEARBORN – To say that CFD is easy as 1-2-3 would probably be an overstatement, but the numbers this computer method generated in regards to the 2013 NASCAR Fusion was music to the ears of Ford Racing.
“Computational Fluid Dynamics is an engineering tool used by various industries in the world for looking at aerodynamics on the computer,” said Ford Racing NASCAR Program Manager Pat DiMarco. “Basically, it’s a wind tunnel on a computer and we at Ford Racing use it in similar ways that Ford Motor Company uses it – to make better, more efficient cars.
“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,” he continued. “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.”
And with a relatively short 18-month timeline to design, build and test a brand new NASCAR Sprint Cup Series stock car from scratch, methods like CFD became an integral part to the process by working in conjunction with the Ford Motor Co. Design Center and Ford Racing aerodynamicists.
“Today, we’re not allowed to test at any track we race on in NASCAR, so computer-aided and engineering tools like this are becoming more and more valuable, whether it’s simulation where we actually predict what the dynamics of the car is going to be, or CFD which predicts the air-flow of the car,” said Andy Slankard, Ford Racing’s NASCAR Operations Manager. “They’re just becoming the tools that we have to use to be competitive in NASCAR.”
*View video of the CFD process - http://www.youtube.com/watch?v=UIzhqv38V10&feature=youtu.be.*
Led by CFD manager Ray Leto, technical expert Naethan Eagles, and engineer Ted Pandaleon, the 2013 NASCAR Fusion ended up being changed dozens of times without so much as a hand being 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,” said Leto. “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.”
Besides being able to make a series of changes in a short period of time, another one of CFD’s biggest attributes is the ability to show the aerodynamic strengths and weaknesses of the vehicle from a variety of perspectives.
“One of the best things about CFD is that we can see the flow of air over the car. We can see the pressures on the surfaces very easily, so we have an idea of what’s going on as opposed to the wind tunnel, where you just kind of get numbers out,” said Pandaleon. “So we’re really able to pinpoint and focus our development to areas that we know are going to get good results and we know they’re going to act the way we want them to act.”
But with the stated goal of manufacturers in NASCAR for 2013 being more brand identity in their respective models, the process by which performance was calculated in the Fusion had to be altered slightly from the way race cars are usually designed. While still trying to build a car with optimum numbers for downforce, drag and sideforce, the group had to balance that without sacrificing the sleek character lines and overall unique look of the all-new Fusion production car.
“The way I liked to hit this was to take the cue from the stylist and then push out past where he wanted to go -- find out what we could do performance-wise -- 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,” recalled Eagles. “I think the car evolved quite a lot over time, so as we went around different parts of the car, we had to try to manipulate the surfaces to deliver the performance that was required while still hitting the styling cues.
“I think it was challenging but enjoyable nevertheless,” he added. “Anything that is different or approaching the same problem from a different direction is enjoyable and challenging. It’s something that adds to your daily tasks and makes you think a little bit outside the box than you normally do.”
By all accounts, having CFD included in the 2013 NASCAR Fusion project was a major benefit and will continue to be a part of future racing projects.
“The CFD really helped us focus on issues we had along the way,” said DiMarco. “We had our standard process that we use with scale-model and then full-scale testing, but when we hit some bumps in the road we were able to go find a little bit more of this or a little bit more of that, and were able to do it very efficiently and very quickly.”