Flow Illustrator - a simple windtunnel simulator

[cfg83]

QuickLTD -

I used a 256*128 2-color bitmap :

http://ecomodder.com/forum/46370-post86.html - Post #86

I made one for your car, but I can't seem to upload it at the moment. It's only 5KB, so normally it shouldn't be a problem.

I also tried to make a movie on the flow illustrator website, but I think your image has soaked up all the disk space on that website. The 5KB image I made failed with a "disk full" error.

CarloSW2

[QuickLTD]

Oh no its not me with the disk full .. lol I have not tried it in days. I appreciate your help. My email is NY718toFL@aol.com if you care to email the file to me and I will try to make a movie tomorrow.

Thank you
Dean

[Piwoslaw]

Ground effect: I tried a few simulations without any ground and I'd get some weird shockwave effect. It was probably the pressure under the car spilling from the bottom edge of the frame to the top edge, maybe it's the program. Since then I've been adding a 1 pixel ground, but am wondering if that makes it better. After all, in real life the car is moving relative to both the wind and the ground, while in the simulator the ground will be moving with the car, also causing turbulation, etc.

[Brillig]

The 'mirror image' was an approximation the early wind tunnel using engineers used to address the 'moving road surface' problem without having a moving surface neath the car.

The 'partial mirror image' I threw in is in homage to this old idea, I wonder if it has any use? It seems to cause some interesting effects at the rear of the car, the 'bounce' seems to push some mixing back up into otherwise semi-laminar flow areas at the top of the hatch/KAMM area.

I'm really just learning to use this tool, it is lots of fun, even if it is not 'reality'.

[philip1]

thought I'd toss my car on Flow Illustrator and see what happens

http://www.youtube.com/watch?v=tFh7JLWR0lc

[bondo]

I was trying to figure out flow illustrator to put a car I designed into the simulation. Alas, I just can't figure it out. I was wondering if someone who has done this before would mind putting my vehicle on the flow simulator page if it is not too involved.

Here is a photo of the vehicle and a blacked out profile ready to go.

Many thanks for any assistance,

Bondo

[cfg83]

bondo -

Here you go :

http://www.youtube.com/watch?v=bF3eOwMylBs

EDIT: Parameter Settings I used :
Re =2,500,500
dt = 0.01
movie length, sec = 40
visual cutoff level = 40

I used relative pixel dimensions to "guestimate" your ground clearance from the first picture, so the gap is small.

Here is the post-processed image I used :

Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - cfg83's Album: Shtuff 01 - Picture

CarloSW2

[bondo]

I really appreciate you putting my car on the flow simulator. I owe you one.

Looks like there is some fairly substancial wake turbulence. If you go the the post of mine titled "garage job" you can see the rear fins and side air channels which may help reduce the wake. Flow along the top looks pretty decent.

Again, thanks for your help and efforts.

Bondo

[KJSatz]

I don't want to be too much trouble, but could you do this to an 8th generation Civic sedan? Here is a good source image:

http://l.yimg.com/dv/izp/honda_civic...PGd047Ks0QFA--
or Slideshow - 2009 Honda Civic Sedan DX 5-Spd MT - Yahoo! Autos

Mine actually doesn't have the mudflap-esque items behind the wheel wells...though I think you're shooting for a center cross section anyway, right, so those wouldn't affect it. Much appreciation.

[cfg83]

KJSatz -

Here you go :

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

Parameter Settings I used :
Re =2,500,500
dt = 0.01
movie length, sec = 40
visual cutoff level = 40

CarloSW2