Turbulent energy or turbulent viscosity
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. |
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 |
All times are GMT -4. The time now is 18:47. |