Question of the day

2b1ask1

2b1ask1

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Indeed a variable flow needle jet was he and his brother Thomas's first major improvement in carburetter design...
 
drewf

drewf

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7,159
Is it me then?

What's a vortex street? Why did this affect Ferrybridge Power station 50 years ago?
 
drewf

drewf

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Certainly did pull down the cooling towers, but it's not a freak wind.

Clue: what do the spirals do on tall (usually) metal chimneys?

If you don't know about this effect, Google it; the videos are beautifully hypnotic.

Spoiler: watch this https://www.youtube.com/watch?v=IDeGDFZSYo8 but you have to wait for it...
 
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2b1ask1

2b1ask1

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Very interesting but now I've Googled it under the rules I cannot answer it now... Oh the dilemma!
 
2b1ask1

2b1ask1

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I know the effect (if not its name) from the Tacoma Narrows Bridge (or galloping Gerty as it was better known)! I have an interest in bridges and that was meant to be my path through uni had I gone!
 
midlifecrisis

midlifecrisis

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Is it where the wind at a certain speed vibrates the chimney or causes some harmonic action to destroy itself. The spirals deflect or disrupt the air flow.

You only have to look at a English Electric lightning to see that wings don't really work.
 
drewf

drewf

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Not quite - that bridge wasn't destroyed by a vortex street. That was aerolastic flutter... similar, but not the same.
 
drewf

drewf

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midlifecrisis said:
Is it where the wind at a certain speed vibrates the chimney or causes some harmonic action to destroy itself. The spirals deflect or disrupt the air flow.

You only have to look at a English Electric lightning to see that wings don't really work.
Click to expand...

Yep, that will do.

The cylinders cause a repetitive harmonic vortex, which at the right Reynolds number (complex explanation) will actually destroy the chimney!

Watch some videos of the effect - they are truly beautiful to see.
 
allandwf

allandwf

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lol, I'm loving this ;) Reynolds number eh? Tell them it's dimensionless, and a constant to ascertain flow is laminar or turbulent. Much more educational then say who won some meaningless cup in history etc.
 
Zep

Zep

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allandwf said:
lol, I'm loving this ;) Reynolds number eh? Tell them it's dimensionless, and a constant to ascertain flow is laminar or turbulent. Much more educational then say who won some meaningless cup in history etc.
Click to expand...

Also proof that you definitely don't want to go to the pub and discuss physics!
 
midlifecrisis

midlifecrisis

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16,281
Is it me? Sorry been working hard doing financial budgets for next year...
Erm give me a minute to think of a non-aerodynamic related question... Lol
 
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