WAsP CFD

Capture1The purpose of the WAsP CFD model in windPRO is to enable the windPRO user to calculate the wind resources in semi-complex or complex terrains.

Requirements for WAsP-CFD

WAsP CFD in windPRO works much the same way as a traditional WAsP analysis and it needs the same data for the calculation, i.e. at least some wind data, a digital elevation model and a roughness model. Due to the very demanding nature of the CFD calculations, the actual CFD analysis is made on the Cerebrum highperformance computer cluster operated at EMD.
The model is capable of calculating both a wind resource maps and individual wind turbine positions, but the actual CFD-analysis is always done in tiles with the central domain sized 2 km x 2 km.
In order to operate the WAsP-CFD model in windPRO
you will need:
Capture2· WAsP 11 (or higher)
· windPRO 2.9 (or higher)
· Calculation credits on the Cerebrum cluster

Calculation credits can be purchased from EMD.

Terrain data for the CFD-analysis

The WAsP-CFD analysis is very similar to the WAsP analysis and it requires the same data – but with an extended 20 km distance requirement for the orography. In this guide we assume that you have already prepared the data for WAsP, so our assumption is, that you have already process your wind data, made a roughness-classification as well as added the height contours within an eight km distance from the site.

Now, the terrain data needs to be prepared for the CFD analysis, as the CFD model requires the orography in a distance not less than 20 km from the site. The WAsP CFD model consumes height contours (not gridddata). These contours can be stored or created from either in a line-object or in a grid-elevation object. Please note, that WAsP CFD is able to handle not more than two million points. windPRO will check if your terrain data meet this requirement.

Orography in a Line Object

Capture5Assuming that you have your ‘normal’ WAsP orography data in a line object covering a distance approximately 10 km from your site, then just press the ‘extend’ button in the line object to add the extra contours to your existing local data. In the far field, the 10 m or 20 m contour separation is fully sufficient.

Contours in a Grid Elevation Object

If your original elevation data originates from gridded sources, then it may be advanteous to store the data in a grid elevation object. If your data covers a distance less than 20 km from the site, then you must add more data from other sources such as SRTM. It is sufficient if you use a contour separation of 10 m or 20 m in the out zones.

Roughness Lines

Roughness lines should cover an area not less than 20-30 km from the site.

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