1 / 25

Wind Farm Noise Impact Assessment WIND SHEAR

Wind Farm Noise Impact Assessment WIND SHEAR. Wind shear ……. what is wind shear ? how does wind shear affect wind farm noise ? how should wind shear be dealt with ?. V u. V L. What is wind shear ?. What causes wind shear ?. ground roughness. V U. log(H U /z 0 ). x. V U. =. V L.

Download Presentation

Wind Farm Noise Impact Assessment WIND SHEAR

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Wind Farm Noise Impact Assessment WIND SHEAR

  2. Wind shear ……. • what is wind shear ? • how does wind shear affect wind farm noise ? • how should wind shear be dealt with ?

  3. Vu VL What is wind shear ?

  4. What causes wind shear ? ground roughness

  5. VU log(HU/z0) x VU = VL log(HL/z0) HU VL HL Modelling wind shear due to ground roughness z0 = ground roughness length ground roughness

  6. What causes wind shear ? atmospheric effects

  7. What causes wind shear ? atmospheric effects

  8. What causes wind shear ? atmospheric effects

  9. What causes wind shear ? atmospheric effects

  10. m HU VU x VU = VL HL HU VL HL Modelling wind shear due to atmospheric effects m= shear exponent atmospheric effects

  11. 8 80 6 40 80 Hourly averaged wind speed, m/s 20 4 10 2 00:00 06:00 12:00 18:00 24:00 Time of day, hh:mm Diurnal variations in wind speeds Height above ground, m After G.P van den Berg, WTG Noise 2005, Berlin

  12. Diurnal variations in wind shear Wind shear is generally highest in evening/night which are measured under ETSU-R-97

  13. Wind shear as a function of wind speed

  14. Diurnal and seasonal variations in wind shear all wind speeds

  15. Diurnal and seasonal variations in wind shear 3 m/s to 5 m/s wind speeds only

  16. Diurnal and seasonal variations in wind shear 6 m/s to 8 m/s wind speeds only

  17. VH V10 Why is wind shear important for wind farm noise ?

  18. Wind shear – effect on turbine sound power

  19. ETSU-R-97 Wind Farm Noise – setting acceptable limits ETSU-R-97 sets noise limits as a function of 10m height wind speed

  20. Source Sound Power Level ETSU-R-97 Noise Limit Wind Farm Noise Immission Level Calculating wind farm noise at receptors Wind turbine noise emissions are also specified as a function of 10m height wind speed Noise Propagation Calculation Algorithm Standardisedfrom hub height

  21. VH V10 Using a hub height mast only + background noise and turbine SWL’s both related to the same ‘real’ wind speed + requires no assumptions about site specific shear profile - typically requires >50m high mast

  22. VH V2 V1 V10 Using measurements at two heights + Similar to first method + Lesser measurement height: use shorter mast and shear measured between two heights to extrapolate up to hub height - typically requires up to 50m high mast

  23. VH Wind speed at 10m height (m/s) V10 Using a 10m mast only + cheapest and easiest option - Need to have data or make assumptions on shear profile on the site + IOA GPG provides simplified corrections for use

  24. Wind shear is important for wind farm noise … and best practice guidance is contained in the IoA GPG

More Related