Will an offshore windfarm offer a lee in a gale?

[Bishop Terrorchoke]

As this point has been lost in the thread it originally appeared in I thought I would bring this up again. Will there be a decent lee offered downwind from an offshore wind farm and if so how pronounced will the effect be and how far will it extend? Can anybody make any sensible estimates?

BishopT

 

[Plomong]

I would expect the effects to be negligible, other than the increased turbulence, for two reasons: 1) the wind turbines are themselves quite well separated, and 2) the area swept by the blades is mostly if not entirely above the masts of the boats sailed by forumites. Some effects would be felt, I'm sure, especially turbulence, but it would not amount to anything like a significant lee.

Sorry to disappoint you.
Plomong

 

[sarabande]

It's almost the opposite; there may be more turbulence downwind of a set of turbines.

Turbulence downwind of turbines has been well studied (e.g. University of Illinois at Urbana-Champaign (2008, December 17). Answers To Huge Wind-farm Problems Are Blowin' In The Wind.

Windturbines may therefore increase the turbulence downwind for a long distance, not only by blade-induced turbulence, but also by slowing down the wind at lower levels, causing higher winds to tumble down into the wind shadow.

Some work on inter-turbine interference indicates that turbulence can last downwind as much as 5 times the blade diameter.

www.meteotest.ch/cost727/eisundfels/pdf/seifert_spacing_windfarms.pdf

 

[Bishop Terrorchoke]

That's a bit disappointing.

BishopT

 

[sarabande]

an additional factor is that wind farms tend to be set in shallower depths, so there may be increased wave/sea bed interference. Could be quite uncomfortable.

Anyone from the East Coast got any direct pragmatic experience please ?

 

[NormanS]

Shut Down

It seems that wind farms tend to shut down when it gets too windy for them. So they're no use when it's calm, and they're no use when it's windy. Doh.

 

[DownWest]

Not sure of the analogy, but Vovo Duoprops have the smaller one behind as it works better in the wash from the forward one. So they do the same work. For wind farms I suspect one should keep well away. Or vote against them as a waste of resources. Unless you want one in your backyard and copp the nice earner.
A

From this you will devine I am not a fan (pun irrelevant)

 

[johnalison]

I have sailed through a very large wind farm in Danish waters, south of Falster, but only once. There was about 15 knots of wind generally, but we lost almost all wind while sailing through, and as it was a fine day thought the wind had dropped, but a few miles after leaving (having motored downwind) the wind picked up again to the original 15 knots. I can't remember the exact distance, but we got the impression that the wind farm had killed the wind within the farm and for a few miles outside.

I don't think there was enough wind to judge turbulence, but I rather think that with that much energy taken out it wouldn't be a problem. No doubt we will all learn more about it soon.