spatial variation of wind speeds between sites l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Spatial variation of wind speeds between sites PowerPoint Presentation
Download Presentation
Spatial variation of wind speeds between sites

Loading in 2 Seconds...

play fullscreen
1 / 18

Spatial variation of wind speeds between sites - PowerPoint PPT Presentation


  • 138 Views
  • Uploaded on

Spatial variation of wind speeds between sites. Andrew Quinn. Why consider wind?. Many problems require a knowledge of the natural environment Design and construction, Transport risk analysis Pollution control, Pollen and aphid movement Wind Power, Forestry management, etc etc

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Spatial variation of wind speeds between sites' - minna


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
why consider wind
Why consider wind?
  • Many problems require a knowledge of the natural environment
    • Design and construction, Transport risk analysis
    • Pollution control, Pollen and aphid movement
    • Wind Power, Forestry management, etc etc
  • Some require single design values
  • Others require distributions
wind speed distribution
Wind speed distribution
  • How does this change with site?

Data from Shap Meteorological site, hourly maximum gust 4/1994 – 3/2003

general form of the cdf
General form of the CDF
  • Weibull distribution
    • Where c and k are site specific constants
    • Fits both mean hourly data and “gust” data
extreme value analysis
Extreme value analysis
  • Majority of previous studies
  • Typical approach is to take linear approximation to the tail of the distribution
  • Where LHS is known as reduced variate
gumbel plot
Gumbel plot

Data from Shap meteorological site - hourly mean and gust up to 1 year return period

extreme value analysis7
Such approaches require long data sets

Therefore not local to sites of interest

Peak values

Gumbel plot of Shap gust extrapolated to 50-year return period

Extreme value analysis

Shap data hourly mean and gust up to 1 year return period

design wind speed methods for dealing with spatial effects

Miller et al (1998) Fig. 5. Estimated 50-year return hourly-mean wind speed for the United Kingdom. Values given in m/s.

Design wind speed methodsfor dealing with spatial effects
  • Wind Speed map methods
    • BS6399:Part2, Eurocode 1, ESDU
  • “Wind Atlas” method

After Abild et al (1992)

objective
Objective
  • Obtain a wind speed distribution for a site:
    • Objective (no subjective estimates of parameters)
    • Realistic (rather than a conservative design value)
    • Based on short-term data records
    • Consistent with other methods (EVA)
approach
Approach
  • Consider the wind distribution at two sites
  • Where cA and kA known (from long records)
  • Define UB+ such that
approach11
Approach
  • For consistency with standard EVA where

assume kA = kB (i.e. distributions same shape)

  • General form E(UB+) ≈ E(γUA)
solution
Solution
  • Thus we know
    • Long term wind speed probability distribution from a reference site
      • Can calculate expected wind speed & return period
    • Relationship between two sites
  • Objective 
  • Realistic 
  • Small data set 
conclusions
Conclusions
  • Method for objective, realistic estimates based on short term site data
  • Data from 8 sites used and estimates for hourly mean and gust wind speeds
    • Accuracy level similar to direct MO records
  • Wind direction can be a significant factor
spatial variation of wind speeds between sites18

Spatial variation of wind speeds between sites

Acknowledgements

Roger Hoxey, Chris Hampson, Nick Teer and the other members of the project team at SRI

Russell Pottrill, William Bradbury and David Deaves (Atkins)