Can surface roughness on wings improve performance

[MattH150197]

Homework Statement

I have a project to research the effect of surface roughness on wing performance. I found mostly that roughness leads to increased drag on a wing, however came across a website that briefly spoke about how recently researchers have observed how carefully selected roughness can suppress turbulent flow on the wing by delaying the transition point so that it is further back on the wing or even past the wing. However i am struggling to find actual research papers on this so does anyone know where to find more information on this, or could share any knowledge that you have on this subject yourself. Thanks!

 

[Nidum]

Turbulator

 

[rcgldr]

The idea of roughness or a turbulator is to cause the transition from laminar to turbulent flow to occur sooner, to reduce or avoid a separation bubble that increases profile drag. For fiberglass gliders, 600 grit wet sandpaper may be used to rough up the wings.

Since the links to web sites often change, I recommend doing a web search for "glider 600 grit" and also "glider oil flow". Oil flow tests involve putting a thin layer of oil on a wing, flying or testing the wing at speed, and noticing where the oil is not blown off by the air flow, which indicates a separation bubble.

 

[MattH150197]

Thanks for the quick responses! I've had a quick research on turbulators but it seems that they are not used on commercial aircraft, unless I am mistaken which i may be, why is this?

 

[CWatters]

Related...Vortex generators are sometimes used on commercial aircraft...

https://en.m.wikipedia.org/wiki/Vortex_generator

 

[CWatters]

Perhaps see also...
http://www.edge.aero/single-post/2016/04/17/Taming-Turbulence-With-Tape-Conformal-Vortex-Generators