Belly pan or vortex generators?

[Otto]

Originally Posted by COMP

where did you get that ???

Ditto!

BTW, if you can find or make tape of the right thickness, you can easily make zigzag tape with pinking shears.

The guys who sell zigzag tape to the sailplane crowd will only sell it in compete rolls, or so they say.

Maybe you could make dimples by making spots of clear silicone bathtub caulk from a tube, dabbed on. This might effectively duplicate the dimples that BMW and others cast onto their mirror housings, as seen in the E36 325i et al.

[Ophbalance]

Heh, the missus has a slew of crafting scissors that can make any type of zig-zag imaginable. I'm making me some of this .

[Otto]

Originally Posted by Ophbalance

Heh, the missus has a slew of crafting scissors that can make any type of zig-zag imaginable. I'm making me some of this .

The stuff they use on sailplanes is pretty thick, maybe 0.030" or more. You might want to layer the tape to that thickness, then cut it with pinking shears.

FWIW, the sailplane stuff has the innie and outie zizgags parallel, if that makes any difference.

The little turbulator bumps on my Bimmer 3 Series mirror housings are about the same height, i.e., ~0.030".

I suppose the turbulator has to be a given height to trip the flow optimally.

[COMP]

Originally Posted by Ophbalance

Heh, the missus has a slew of crafting scissors that can make any type of zig-zag imaginable. I'm making me some of this .

what kind of tape are you going to use ???

[Ophbalance]

Don't know. What's weather resistant and sticks to auto paint?

[Otto]

Originally Posted by Ophbalance

Don't know. What's weather resistant and sticks to auto paint?

Why not use the pinking shears and tape to make a zigzag stencil, then put on some clear silicone bathtub caulk as the turbulator, peeling off the stencil before the caulk firms up. That caulk is transparent and has a ~50 year life, so you wouldn't have to paint it. Build up in layers to desired thickness. Tough stuff.

[COMP]

Originally Posted by Ophbalance

Don't know. What's weather resistant and sticks to auto paint?

and how thick does it need to be to work ??? also want to be able to wax ??

[donee]

Hi Edbso,

I think that is a good idea. Even the Prius has the vortex at the top of the A-pillar. I can see the swirling/stagnation of the rain on the driver's window there. Some concept next generation Prius have shown side dams there. But, that is allot of extra drag possibly, due to the air going sideways, and not up over the roof axially. So, putting in a turbulator is probably just the thing. It will chop up the big vortices into little ones, which have less cross-section (boundary layer height). At least that is my guestimate of why its quieter.

[edbso]

So I found this interesting piece about work being done on the airflow over a glider wing

What particularly impressed me was the lightness of the material, Zig-Zag tape. AND it works.



I also took the opinion that if I made a big error in placement there likely would not be huge negative effects.

To help visualize how the laminar bubble would look during qualitative wind tunnel cession the testor used vaseline plus TiO2 mixing as a surface liquid for visualization. The result could be clearly seen thanks to UV light.


The before shot of disturbed air flow over the wing.


Now the attempts and final fix.

Starting with straight tape...not much result.



Now Zig-Zag tape placed on a diagonal too test for positioning. Big improvement in areas.



And the final result.



I think that the results are dramatic and IF one makes a huge error in placement I don't think that there will be a huge negative effect.

When I put the tape on the rear view mirror I couldn't tell that there was a difference. When I put it on the A pillar the reduction of the air aka wind noise was dramatic. A huge improvement.

So in summary...
It appears to work...
It is inexpensive (Dymo tape) cut with pinking sheers...
It is light and
I like that it is "quirky".

[edbso]

This is the airflow that I have over the A pillars.
Basically horizontal so I placed the tape perpendicular to the flow.





I hope that I have energized the air across the side windows. Should be able to tell during a rainy day.

I also have to wonder whether a positive effect can be had by placing the Zig-Zag tape at the trailing edge of the Matrix?