Zig zag strip etc

Has anyone tried zig zag or dimple strips on their gear leg fairings?
It seems to me, with the relative thickness of the leg fairings, that a certain amount of separation can be expected... which to a certain extent can be overcome with zig zag or dimple strips...

You can tuft the fairings (or use an oil film) and check out your hypothesis. If it holds true, then you'll probably see that separation occurs near the trailing edge. If so, change their shape so that it has a reflexed trailing edge, like Van's wheel pants, that should cure the problem.

The reflex will aid both with a more favorable pressure recovery and an increase in Reynolds number.

I think this might be more efficient than forcing it to go turbulent at the leading edge - but you can try that and see.

Please report back. Thanks!

Dave

I did some tufting, however mostly of the wheel pants and fillet, which showed separation in 2 areas. I did see some separation from the leg fairing as well though.



CFD analysis shows that there is some separation..



I am currently working on various mods to the fairings and fillets.




I have ordered some zig zag tape and will try it on eventually!

hlangebro said:

I did some tufting, however mostly of the wheel pants and fillet, which showed separation in 2 areas. I did see some separation from the leg fairing as well though.

CFD analysis shows that there is some separation..

I am currently working on various mods to the fairings and fillets.

I have ordered some zig zag tape and will try it on eventually!

Click to expand...

Are the Facebook pictures viewable by anyone? I get an error.

Edit/update: Nope - still not working for me.

They are all posted as "public", so they should all be available....

I get "Sorry, this content isn't available right now" when i click the links

turbulator stips....where and why?

I find it amazing that these aren't more widely used.

I recently saw a Stemme motorglider, had them EVERYWHERE, I was surprised that they were 1 to 2 mm thick; I guess that's a function of the boundary layer on that particular airfoil or some such thing. they were mostly in front of control surfaces, on both sides of the wing, stab, rudder etc.
apparently they felt they were worth the slight drag penalty to keep the flow attached...on something as drag sensitive as a glider.
I can imagine a dozen dirty airflow places on our aircraft that would benefit.

The reason is two-fold, keep the boundary layer attached and reduce drag. If you have separation and use a zig zag to keep it attached, it will result in a drag reduction. I dont think anyone would use them if the drag went up... unless it was for controllability/crosswind performance and such.