Turbulent energy or turbulent viscosity

Victor Reijs · January 31, 2024, 13:43

A beginners question. Say I have a traditional wind mill in a built environment and I want to understand the extra turbulence at the location of the wings (compared to a free field location).
I expect that turbulence will add extra wear and tear forces to the sails.
Which parameter best described this resulting wear and tear force: turbulent energy of turbulent viscosity?
And how do I compare the built values with the free field values: subtract them of divided them or???
If there is some literature/webpage where such a comparison between two different situations (in my case: built en free field) is described (related to wear and tear), that would also be helpful.
Thanks for your help!
All the best,
Victor

P.S. I was thinking to compare the turbulent kinematic energy: determine the 'standard deviation' instead of TKE: sigma(built)=sqrt(2*KTE) en then compare this sigma(built) with the speedmagnitude(built): sigma(built)/speedmagnitude(build))=relative(built).
Do the same for the free field (relative(freefield)) and then compare these two.

Victor Reijs · February 1, 2024, 01:27

Looked at this video https://www.youtube.com/watch?v=Xr7BzHImL68, and this web page: https://www.cfd-online.com/Wiki/Turbulence_intensity; Turbulence Intensity might be very close to my idea.
So following that:
If I look at an ABL flow (6.44m/sec @10m and z0=1m) I see at 12.5m height; a speed |U| of 7.2m/sec and a KTE of around 1.6m2/sec2. and this gives an I =sqrt(2KTE)/|U|=sqrt(21.6)/7.2=25%
So his boundaries (1, 5% and 20%) do not really work for an ABL environment. Where do I go wrong in my thinking?

Thanks for your feedback.

All the best,

Victor

January 31, 2024, 13:43	Turbulent energy or turbulent viscosity	#1
Victor Reijs New Member Victor Reijs Join Date: Jan 2024 Posts: 14 Rep Power: 2	A beginners question. Say I have a traditional wind mill in a built environment and I want to understand the extra turbulence at the location of the wings (compared to a free field location). I expect that turbulence will add extra wear and tear forces to the sails. Which parameter best described this resulting wear and tear force: turbulent energy of turbulent viscosity? And how do I compare the built values with the free field values: subtract them of divided them or??? If there is some literature/webpage where such a comparison between two different situations (in my case: built en free field) is described (related to wear and tear), that would also be helpful. Thanks for your help! All the best, Victor P.S. I was thinking to compare the turbulent kinematic energy: determine the 'standard deviation' instead of TKE: sigma(built)=sqrt(2*KTE) en then compare this sigma(built) with the speedmagnitude(built): sigma(built)/speedmagnitude(build))=relative(built). Do the same for the free field (relative(freefield)) and then compare these two.

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February 1, 2024, 01:27		#2
Victor Reijs New Member Victor Reijs Join Date: Jan 2024 Posts: 14 Rep Power: 2	Looked at this video https://www.youtube.com/watch?v=Xr7BzHImL68, and this web page: https://www.cfd-online.com/Wiki/Turbulence_intensity; Turbulence Intensity might be very close to my idea. So following that: If I look at an ABL flow (6.44m/sec @10m and z0=1m) I see at 12.5m height; a speed \|U\| of 7.2m/sec and a KTE of around 1.6m2/sec2. and this gives an I =sqrt(2KTE)/\|U\|=sqrt(21.6)/7.2=25% So his boundaries (1, 5% and 20%) do not really work for an ABL environment. Where do I go wrong in my thinking? Thanks for your feedback. All the best, Victor