Snow Aerodynamics

[invisiblegold]

Hi, I just wanted to show some photos I took of my Insight last winter. Basically, it snowed lightly and the car was parked between trees for a bit of a "tunnel" effect. 40+ MPH winds blew all night (from the front) and left this pattern in the snow.

1) I moved the car to the sun to get better shots.
2) The snow was light and fluffy and you could blow it away with your lungs if you really tried.

http://www.waiveris.com/projects/hon...ht/aerophotos/

The interesting thing was seeing where the snow didn't buffet away the snow.

[invisiblegold]

PS: I should also point out that I drove 40 miles later that day (without cleaning the car), and very little blew away. It was at least 3" thick on the back of the car. (and really deep in that "kamff" tail over the bumper.)

[skewbe]

Hmm, interesting, I need an aayrodynamicist to tell me what that means exactly.

Should your hatch be three inches higher?

[BluEyes]

I'm pretty sure what you are seeing are areas with lower airflow velocity. It seems that some are indicating areas of high pressure (base of cowl) while others are indicating detached flow (rear bumper)

I think some of this would be affected by the snows greater density than air, causing the snow to settle out when the airstream is in fact still flowing normally?

I wonder if that is indicating that the Insight might do better with a Kamm-back shape though?

[James]

Here's a guess: If you filled in the areas where the snow settled, Cd would be reduced. because of the kamm back, you cannot see the areas of turbulence in the back...I am certain that a boat tail would improve the cd of the insight, but the engineers (or someone else)didnt think it was worth it.

[thisisntjared]

Originally Posted by James

Here's a guess: If you filled in the areas where the snow settled, Cd would be reduced.

i think thats a half truth. it shows where the air is still, but not necissarily the pressure. pressure would be the best indicator of changes that need to be made, since the best way to improve the aerodynamics is to make the pressure around the entire vehicle as uniform as possible. lets also not forget that gravity has an effect on some of the placement of the snow so its not everywhere that it is still, but everywhere that it is still and has room for the snow to fall.

[red91sit]

haha, i want to know the story behind that. I've also been noticing weird patterns where snow accumulates on my car. Mostly the very back has a very sharp cut off on the tailights and completely covers the back. Also if i dont' sweep it off the middle of the roof cleans off and leaves two large ridges on the sides of my roof haha. The snow from the roof slides back onto the trunk and rear window and settles in the middle while the edges clear off.

Interesting pictures at any rate!

[VetteOwner]

well my chevettes weird. it will be parked on a level surface but the whole engine compartment will have snow in it. i will have a good few inches sitting on top my air cleaner cover...

[red91sit]

Perhaps it's flying up from the bottom while your driving?

[BluEyes]

More likely being pushed down by the high pressure area at the base of the windshield and then into the engine bay. Is the rubber seal at the back of the hood intact?

[VetteOwner]

noticed i said PARKED! but its a chevette, there is no seal...

[trebuchet03]

That's really cool.... That would be nature's attempt to fix what's wrong with the design Trying to get closer to that natural teardrop shape. It also shows the importance of the rear end (meaning - downstream features) with respect to aerodynamics.

If you wanted to find the ideal shape nature intended (if nature intended cars :P), build up some light and fluffy snow - enough to cause trouble with flow. Then hit the highway and let the snow blow off.... Of course, that won't work beyond the bumper very far :P

Again, that's really cool - I don't live an a region that snows so I never get to see anything like this on my vehicle :P

[nathan]

Originally Posted by VetteOwner

noticed i said PARKED! but its a chevette, there is no seal...

actually there is a seal, or at least there should be.