Those fairings on engines, what they for?...

[rmk2112]

Hi All

I was wondering what the purpose of those thin metal fairings, I'm not referring to the wings..., that are attached to the sides of engine casings . They often say "No Step" so not for engineers to stand on, are at an angle so no good putting their tools or beer on as would just slide off....
Regards
René

[pilotgolfer]

I believe it has something to do with vortices.
I'm not exactly sure, though.

[saupatel]

That is where we see the cool vortices forming when an airplane rotates. Other than that I have no freaking clue. Always wondered their real purpose myself too.

[AJ]

They are chines (also known as strakes). They are designed to smooth and direct the airflow from the nacelle over the wing.
In the photo you can see the flow clearly thanks to condensation:
[photoid=446382]

[rmk2112]

Thanks guys for the info
Regards
René

[Jan-Jasinski]

I did not know vortices come from that spot sometimes! Learning something again!

[Taliesin]

They are chines (also known as strakes). They are designed to smooth and direct the airflow from the nacelle over the wing.
In the photo you can see the flow clearly thanks to condensation:
[photoid=446382]

Actually, the purpose is not to smooth the airflow, but to make it more turbulent. The resulting vortex increases the interaction of the boundary layer with the more distant airflow and decreases the tendancy of the boundary layer to separate. This is needed because at the attachment point of the engine pylon, there is no room to install a slat, so the job that the slat is usually doing needs to be achieved some other way.
That's what the strake is for.

[AJ]

I had tried to simplify the explanation, but 'smooth' is a poor simplification I agree!
We could go down the dimples in a golf ball route hover I don't think that level of insight was wanted!