Tuft testing! 1998 Ford Escort ZX2 (front hood, windshield and rear glass and lid)

[BabyDiesel]

I have said I was going to do this for a long time. Life seems to always get in the way of scientific studies when you are a layman scientist However, I made today it!

Photos of the areas tested:





The reason for the fewer number of tufts on the front is because I ran low on time. My brother was the camera man, and he had homework to do. I had to make do with what I had. It told me all the info that I needed to know though I added the windshield wiper cover today in an effort to reduce rear turbulence, hence it was not painted. Whether it helped or not in unknown, as I did not perform ABA testing.

Here is the video:

https://www.youtube.com/watch?v=1JVBeoA89Pw

Excuse my brother and I. We tend to act goofy when we get together, research or not

I have another video that will be uploaded tomorrow that shows the rear lid better, and has a panned out shot of the entire rear glass.

What I infer:From what I can tell, there is attached flow on the hood and the windshield. I was concerned that there was turbulence there. On the back, it is a mess! It is all turbulent, except for maybe the tufts on the top of the rear glass and around the brake light. *There is semi-attached flow and a vortex there, respectively*.

*Of course, I am no aero expert. So I await the aero gurus to dissect the results of this test so we really know what is going on

[BabyDiesel]

Bumping for the hope that someone can tell me something about the aerodynamics of the back glass

[aerohead]

there will be a downwash off the roof which will tend to hold the tufts backwards but won't reveal attached vortices on each side of the roof top if they're there.Smoke is great for showing them.

[BabyDiesel]

Originally Posted by aerohead

there will be a downwash off the roof which will tend to hold the tufts backwards but won't reveal attached vortices on each side of the roof top if they're there.Smoke is great for showing them.

I have seen vortices in rainy conditions. When I look back, the spray kicked up is spinning on either side of the car and trailing back maybe 20' off the rear. It appears to start on either side of the roof, near the rear pillars, and are spinning down to about 2' off the ground. Roughly the height of the rear bumper.

I'll try to get a diagram drawn to show what I have seen

All I know is there is very turbulent flow around 90% of the rear, with a center lock vortex starting about halfway down the center of the middle of the rear glass, and extending down to the trunk top.

[MetroMPG]

Originally Posted by BabyDiesel

What I infer: On the back, it is a mess! It is all turbulent, except for maybe the tufts on the top of the rear glass and around the brake light. *There is semi-attached flow and a vortex there, respectively*.

I agree - I think you've got a little bit of separation/recirculation right around the center mounted brake light.

Most of the time the tufts are sitting relatively still, but every once in a while you see one going sideways & backward.

To me, it looks pretty good. Recirculation/locked vortex is much more evident on the back window of an '07 Civic or '06 Corolla that I tuft tested:

Civic:



Corolla:

https://www.youtube.com/watch?v=We8LWkqjdX4

[MetroMPG]

Did you make the video of the trunk lid? The few seconds you can see it in your vid, it looked OK. Turbulent, but attached flow.

[2000mc]

Without seeing major issues, I think it's hard to read into too much

I though arcosine's tuff test on his spoiler-less sc1 looked pretty hard to beat - http://ecomodder.com/forum/showthrea...tml#post325746

...but my scangauge says my modded spoiler beats no spoiler, even though my spoiler is far from optimal with sawed off ends - http://ecomodder.com/forum/showthrea...tml#post467518

[cRiPpLe_rOoStEr]

Sounds like a good excuse to make experiences with a Kammback.

[aerohead]

here's an image Hucho shared in his text.

[freebeard]

It appears to start on either side of the roof, near the rear pillars, and are spinning down to about 2' off the ground. Roughly the height of the rear bumper.

I buy into BabyDiesel's description more than Hucho's. I think the vortexes flatten and spread.