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WAsP 11.2


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Today we release WAsP 11.2.

You can download it from here:

We have made some changes to the core model to fix problems with CFD flow result treatments at unusual sites. You should probably re-calculate existing projects, but don't expect any significant differences in most cases.

Good news: this doesn't affect your CFD result tiles so there's no need to recalculate those.

There are more detailed release notes here:

Best wishes, Duncan.
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Dear Duncan and WAsP team,
thank you for the continual improvements of WAsP software.

However, I have a problem with the new limitation in the actual release. Sometimes I need to use old wind atlas files that employ "classical" roughness classes of 0.00, 0.03, 0.1 and 0.4 m. But I found that now WAsP does not perform with these wind atlases at sites, where the reference roughness of any sector is higher than 0.4 m. In such cases the report appears: 'climate calculation: meso-scale roughness lies outside gwc roughness classes.'
I suppose that this was announced with the new release as "Stricter calculation constraints for site lying outside wind atlas classes".

For me it is a good point to be aware, when the calculation can be incorrect by this issue, but in some cases I do not have an option to avoid using old wind atlas. Would it be possible just to alert but not disable the calculation? How big errors would occur then? Are the new model versions more sensitive to this issue than the older ones?

Or, if this change is definitive, could you advise me how approximately recalculate wind atlas files in order to add high roughness class? (other way than by using original map and wind climate)

Thank you
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Hi David,

Thanks for your message. You've made a good point. It could be that this change affects more cases than we expected. I actually found this problem with the WAsP 10 sample data!

I will urgently check with the scientists to see what they recommend.

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Hi everyone.

So far not too many people have this problem, but we've worked out a solution and will try to update this week.

WindPro users are having problems getting the wind profile calculation to work, because it starts near the ground: lower than the lowest height class. We plan to relax this constraint, but the real fix is to change the settings for the profile calculation so that it doesn't go below the minimum height.

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Hi everyone,

We have made a WAsP update which fixes a couple of GUI bugs and makes a small relaxation of the constraints. Unfortunately, we cannot really remove the rule which says that you can predict for a meso roughness length greater than the maximum roughness class in the atlas. This extrapolation is just unsafe. But we have no restored the ability to extrapolate down below the lowest height in the atlas.

You can download Release B of WAsP 11.2 from here:

We are working on making changes which will allow you to perform a deliberate, one-time extrapolating change to your wind atlas to add a new, higher roughness length. But we really recommend that if at all possible, you should re-calculate the atlas in this case. That's the only safe and correct thing to do.

Best wishes,

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If you are getting a message like

"meso-scale roughness lies outside gwc roughness" as an error, or if you can't calculate some site because "the atlas range does not include the site roughness", then you need to re-calculate your Generalised Wind Climate (GWC) with different settings. In fact, the new (WAsP 10.2) default settings are probably what you need.

So, I suggest that you do this (assuming that you have the met station data to allow you to recalculate the atlas)...

1) Move (drag) the GWC and its child met. station to the workspace root
2) Insert a new GWC to the project. I will have the new default max roughness of 1.5 metres.
3) Move (drag) the child met. station back to the project under the new GWC
4) Re-calculate the atlas and then its derived predictions

If you have a site where the meso-scale roughness in one sector is greater than 1.5 metres (?!), then you'll need to change the defaults before creating the new atlas. To do this, right-click on the project and choose "Edit configuration for member". Then expand "wind atlas structure", and select "standard roughness length #5", and edit that upwards.

Hope this helps. For those who can't actually recalculate their old GWCs (Libs), we will try to offer you something soon.

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  • 1 month later...
Dear Duncan and WAsP team,

I've already updated WAsP from release 11.1 to 11.2 and got the same error message as mentioned above (messages from 12/2014)while recalculating a few recent projects ('climate calculation: meso-scale roughness lies outside gwc roughness classes.'). Unfortunately, I can't recalculate the old GWCs (Libs). Is there now any possibility to recalculate anyway?

Best regards and many thanks you for your help in advance.

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Sorry that you are stuck with this problem. We're preparing a tool to help, but I don't know when it will be ready to ship. While we make the tool, we could run it on your lib file and send you back an extrapolated one. Just email us the file and we'll do something ASAP.

Best wishes, Duncan.
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