BrianCunningham

Posted over in C4tech

http://forums.corvetteforum.com/c4-t...post1568960321

wallyman424

Thats really neat, but assuming this is accurate, what kind of info can you derive from it?

BrianCunningham

Best height to place a wing

Optimal angle for a spoiler

Here's a C6

eogel

Wallyman,

Nothing you would be interested in! You do not need to be going any faster.

Ed

Everett Ogilvie

This is very cool, and I hope to get some time to play with it, maybe with these two pics...

SuperL98

That shape caught my interest .... so I gave it a try.
Put in a little ground clearance and sized a wing to fit into the side plane shape.

http://www.youtube.com/watch?v=6qeIJZJKhv4



Something about these AVI files Youtube doesn't like ... still

BrianCunningham

moving ground plane?

Everett Ogilvie

Very nice! I tried it briefly, and it did not create a file...

The car has a flat bottom and side skirts which really help with air management. That "squared off" piece on the rear of the car (in my original pic) which you may have removed in your pic, is the race diffuser which definitely helps remove the air from under the car while creating a much smaller pressure drag profile from the flow coming off the back of the car.

Thanks for posting this!

SuperL98

Well, had some time to play a bit more with this program
Looks like you can use a 640 x 480 image, OK
I can than convert it over to an MPG for You tube
Also looks like the Reynolds Number isn't linked to the model size but the Bitmap size.

Everett, I had to take out the vertical surfaces (on the wing and diffuser) because this is just a 2D slice of the car & it would just see them a square blocks.
I assumed the diffuser was shaped like the rear of the car, but you can cut that in, any way you like.
If you try it again, here is the image I used, but you have to save it as a Bitmap, photo bucket converts them to jpeg, don't know why?
It's 640 x 480 pixels.
And I'm now using Re = 20,000 dt = .01 sec = 30 visual = 60
Takes about 12 minuets, you have to wait



http://www.youtube.com/watch?v=Bnj02Tk7D0w

SuperL98

Don't know what you are asking

I put a black block on the bottom of the image to move the model up into view and away from the "Flow Illustrator" logo.

TLGunman

The MT900's diffuser angle is 7deg...I know a guy, that knows the guy that designed it

Interesting piece of software. I'm surprised it doesn't show the high pressure areas on the front of the car, ie the lower windshield, etc., it could be a matter of scale, or maybe I'm just looking for too much.

Everett Ogilvie

I realized that last night (about this simple model only seeing it as a block) while I was in bed - I know, what dork thinks about stuff like that at night...... And you did a good job with your assumption to use the shape of the car in the rear, which should be pretty close. Thanks again!

Yeah, it's a pretty simple model and does not include many items, like the airflow through the radiators being vented out across the front bonnet, creating additional downforce, etc. Still, pretty interesting!

TLGunman

I sent the video link to Warren Mosler last night, and he thought it was pretty cool.

BrianCunningham

does the ground move relative to the car?

If it's fixed, your never going to get the ground effect right.

SuperL98

We have to be careful not to expect too much from this “Illustrator”.
I did find some info on the program.
It’s just a simple 2D modeler that seams to develop flow from the base Bitmap points and assumes all flow is Laminar. He tries to “simulate” Turbulent flow by using what he calls “Turbulent Viscosity” at higher Re values (=> 10,000).
Re number is based on the Bitmap and not the model size.
It should give reasonable results at sharp break off points (like the tail body edges), but the flow may separate at a different point (in real life) on long smooth surfaces (if they develop Turbulence).

I would use this to explore ideas, but not to design anything, for example:

I looked at Cowl Hood Scoops on the Vette and on a Honda Element. Both worked good with an empty engine bay, but when I started to fill up the void with parts (engines, etc.) the Honda kept flowing in (as expected), but at some point the Vette started flowing out?
So I wouldn’t use the program to design the point that the under hood pressure exceeds the windshield pressure (on a low CD vehicle), but more to get us thinking that maybe that does happen? Especially with an engine bay as tightly packed as the C4.









I also started played with things like MAF with and without screen.





I’ve got to get back to some “Real” paying work, but I’ll try to get back and post some more videos sometime.

Going to try to contact the author, this would be a great program for a High School Science or Science Summer Camp.