WAsP changes - could you please give confirmation?

[Gyeongil]

Dear Team

could you please confirm these issues?

1) map size
As I understand WAsP is based on "1:100 rule of thumb" to extend roughness map, and following the rule, the roughness size is normally considered 100 x Hub height.
but now I found out in the WAsP best practices, it is written such as:
/
Size: map should extend at least max(150×h, 10 km) from any site –
meteorological mast, reference site, turbine site or resource grid point
/
are there any reasons for this change from "100xHH" to "at least 150xHH"?

2) "standard height" of Wasp parameter
I found out that since version 11.4 "Generalized wind climate default height range has been changed to 5-300 m a.g.l".
does this mean that "tall tower profile issues" in WAsP has been validated including stability/extrapolation treatment?
I could not find the validation report and I thought it is still under investigation.
Could you please provide the reasons of changes?

BR
Gyeongil

[Brian Ohrbeck Hansen]

Hi Gyeongil,

Regarding your question 2, we decided to increase the generalized wind climate default height range because we had on more occasions been contacted by WAsP users who needed to make calculations beyond the old height range. So this does not mean that we have made changes or improvements targeted at "tall profiles" yet.

Best regards,

Brian

[Niels Gylling Mortensen]

Dear Gyeongil,
Regarding issue 1): the reason for the change is that many users took 100 h to mean the "maximum radius or extent of the map", when it was in fact meant as the "approximate radius of the map". It was always understood that you should add a bit to this number. We made this clear by adding 50% (my favorite safety margin). Conclusion: WAsP Best Practice is to add some to the 100 h distance, e.g 50%.
Best regards,
Niels

[Gyeongil]

Thanks for your prompt answers.

[kedx3mmn]

is there anyway I could adjust the heights between 5 to 300m. Or it is fixed? Thanks

[Duncan]

You can change the heights used when calculating a wind atlas.

If you right-click the project and select "Edit configuration for member..." then find the option "Wind atlas structure" and you'll see five standard heights. Any of these can be adjusted, but keep then in ascending order of height. You can also change the number of standard heights. Next time you calculate a wind atlas it should use these settings.

Duncan.