Posted By Mike Kojima on 02-12-2010 10:03 PM
CFD for dummies?

No kidding.  I've heard that there are reasonably decent CFD packages for desktops, but haven't spent the time to research it yet.

Nascar Car Of Tomorrow

Finally found the camera:

Mounting the COT Splitter: 

Mocking it up on the nose (not exactly my favorite color).  From the marks on the splitter, the NASCAR guys mount these things with a 7" depth.  Wow, pretty deep.

Looks like it'll be easy to mount, plenty of splitter to bolt to the lower nose rail:

I'm going to mount it with a little more than 4" of lip, its going to be a little short on the sides:

Mocking up a strut, I'm a little embarrased to say I was too lazy to fab these, I bought them from a circle track vendor:

I decided to use the holes that were already drilled through the splitter.

The underside of the splitter, they used a 3/8" bolt to mount to the COTs, so I thought I'd do the same.  You can really see the look of the raw Tegris here:

OT: You can see how much we've had to tape up the radiator inlet to try to get heat into the engine:

Nose cover stripped, preparing to mount the top of the struts:

Mocking up the top:

Upper mount:

Mocking up for the bolts.

Its an excellent question, but one that I don't have an academic answer for.   My conjecture is that it would not be as effective, instead of piling up air on top of the splitter and accelerating it under (thereby creating a low pressure area, which creates the downforce you are seeking)  you'd simply be stagnating air in front of the dam. I'm not an aerodynamicist, nor do I play one on the internet. I've read several books, which only makes my advice dangerous.

When faced with those kinds of questions, I look to what top end teams are doing with their cars.  I'm not aware of any team that puts an air dam under a splitter.  I think you could ask yourself if the splitter is actually working properly if you put a dam underneath it. Doesn't that fundamentally change the very nature of the device?  Splitters are getting thicker and thicker, possibly for rigidity and also so that the underside can be sculpted to create venturi to work with flat bottom plates.  

I would suggest that you add the dam to the top of the splitter, allowing the splitter to function properly.  I assume that you can place the splitter as close to the ground as you would have made the bottom of the dam.

Maybe one of the real experts will chime in and address your question.