Flow Illustrator - a simple windtunnel simulator

[donee]

Hi All,

One way to see what the flow would look like on a real good Cd Car would be to run an Aptera in the Flow Illustrator.

[cfg83]

Hello -

Ok, I watched the videos over and over and took some snapshots of what I thought was representative :



Now, the rain drop is most likely the way to go, but I was intrigued by the "stability" of the top part of the third design above. It "looked" like it's not turbulent, but maybe all it's doing is elongating (i.e. postponing) the turbulent wake. And larger volume wake = bad, yes?

CarloSW2

[skyl4rk]

If you look at the area of the red smoke, it does not change very much between versions.

Perhaps reducing the vortex size is a goal in comparing shapes with this software?

Also, I wonder if the effect of turbulence on the vehicle aerodynamics diminishes with the distance of the turbulence behind the vehicle? In other words, turbulence close to the vehicle has a greater effect on the wind resistance measured for the vehicle?

[HyperMiler]

Originally Posted by donee

Hi Hyper....,

That shows flow seperation at the top of the C pillar. Might try some tubulators there.

Thank you for the advice!

[cfg83]

Hello -

I did a one-half snow cone (i.e. rain drop) for Fun :

One Half Snow Cone

YouTube - One Half Snow Cone

Smooooooooooth as silk.

CarloSW2

[basjoos]

Originally Posted by ebacherville

here is basjoos's areocivic:

To be more accurate, some of the vehicle area under the car needs to be removed. That profile includes my wheel spoiler, side skirts, and wheel boattail, which add cross sectional area just to the section of the car next to the wheels. For most of the underside of the vehicle in between the wheels there is more ground clearance and more air passing under the vehicle.

[piekar]

thanks, thats a cool site

[donee]

Hi All,

Because of the 3D nature of Basjoos boat tail, the 2D Flow Illustrator is not going to be very accurate for that shape.

[bbjsw10]

This program is so cool. I have been making bitmaps all night on my car. Trying to see what different rear shapes would be good and still look in the norm.

[Concrete]

This is cool and I like it but not sure how useful it is

Note from the "more info" page of Flow Illustrator

Accuracy
Flow Illustrator is optimised for speed and robusteness, with accuracy being traded in. Treat the movies as artist impressions. The artist is you.

I'm having fun with it - but also having trouble knowing what to trust

The kamm backs and shapes that have turbulence waving way above the roof line are hard to believe. I have not seen smoke, snow or other indicators behave like this in the real world, at least for smooth shapes.

using for an S10 and it is not replicating real life
In the real world there is a strong rolling action behind the cab (yes I have a bed cover)
it dwarfs all other activity in that region from 30 mph up to highway speeds
and my stream lines off the cab are reasonably stable pseudo boat tail shaped
but that sure is not what the Flow Illustrator shows

YouTube - s10 extended cab airflow simulation 60 mph

I will continue to play with the inputs and see if i can get closer to the real world