In my fluid mechanics class the other day at university, our prof put up this picture to emphasize fluid flow properties.
It kinda proves why factory vehicles usually have the air intakes behind the headlights (high pressure distribution), and why cowl induction would be a good idea. This is just a generic "car", but most cars share the basic same shape, so it gives the idea...
Thought i'd share this neat little tidbit of information, I think it was done with a CFD program of some sort.

 

i dont know what im looking at.

 

No need to apologize.

Sonix: that's a great visual!! With the price of CFD software coming down, hopefully we'll be able to gin up a 3rd gen model and start tweaking air splitter and rear spoiler designs.

 

It's the amount and direction of air pressure along the surfaces of the car.

 

oh i totally see the car now. thanks!

 

"Average car?" It looks more like the profile of a '68 Chrysler Newport. I haven't seen a windshield that upright on a passenger car since the early '80s (except on Ford Crown Vics).

If you can, flow this. It has a frontal area of 19.2 ft², a cD of 0.27, overall height of 53.8", and ground clearance at the front and sides of 1½":

 

what is that? like a '90 Thunderbird supercoupe (rear end at least) with '96 Impala wheels...
hmm, i'll see if I can get ahold of that CFD software, maybe they'll let me play with it...
I'd probably need more info too, and I prefer metric personally

 

That pic PERFECTLY shows how a cowl induction hood works!!!

Nice find!

 

excellent flow chart, it shows it perfectly

 

Here is a pic of the G35 we did where I work. The top left pic shows the surface pressure. Redish tones indicate high pressure. The pic in the middle shows the path of a particle flowing by the car. The top right shows a pic of the cad model.

Before it's asked...

No, I can't do your car. I'm still trying to do mine!
Yes, I did work on some of it.

 

Heres another pic. This one shows the velocity of the air around the car at the centerline. The arrows indicate the direction. In this one redish tones indicate high speeds and greenish tones indicate low speeds.

Check out the Gallery section here for more pics of some of the stuff we've done if you're interested.

http://www.erc.msstate.edu/simcenter/

Mississippi State University Engineering Research Center

 

That's pretty cool stuff. One question I have though, is why would you go through all the effort and time to make a CAD model of the car, then use a program that calculates/estimates the flow of air...when you could just take the actual car n' stick it in a wind tunnel and get real results? I don't know a whole lot about R&D, so this may seem like a stupid question... but it just seemed logical to me. I'd love ta learn how to use CAD software though.

 

besides the fact he is learning this in his class?

 

Say your a big racing company and you want to put a spoiler on your car. You can take your car and put a wing on it and run it in a wind tunnel. If you don't like the results then you strap another one on it and go at it. Depending on how fast your machine shop is that could take a while. But with CFD you can stick a wing on there and run it. Then draw another wing real quick and run it again.

With everything being created in computer first anyway it decreases R&D time because you don't have to create the prototype and test it. You just run CFD on the computer model.

 

also wind tunnel testing is very expensize... the University of calgary can only wind test things up to the size of a go-kart for example. It usually gives a good indication as to how a wing/spoiler/front air dam will react with a given shape, then you can tweak it later.

 

Black 91 Z28:

What software are you guys using for the CAD, and for the CFD analysis?

 

It's all inhouse stuff that we (well them) have developed. For CAD stuff we use SolidMesh, for solutions U2ncle, and for the pretty pictures DIVA.

 

Well, you're partly right. It has 17" SS wheels, because it is one of them:

 

..So THAT"S why people dont have their air intakes on the roof...


(and, come to think of it, why roof scoops are a bad idea :P)


nice find!

 

I dunno... McLaren uses one on the F1 road cars and road racing cars, so it must serve some purpose?