This layer type is provided purely to allow the graphical illustration of wake effects due to the various models available in Openwind. The approach taken here is to create a grid of sensor turbines, each 1 m in rotor diameter, spaced 100 m apart by default. Sensor grid layers are a form of gridded site layer but with less versatility. The gridding is only orthogonal and the spacing is equal in x and y.
It is possible for the user to set the properties of the sensor turbine used in a sensor grid layer. The turbine type used can have all the properties of a normal turbine type except that its rotor diameter must be 1 m.
Like the gridded site layer, a sensor grid layer is based on a bounding polygon and fills the bounding polygon with turbines. This can mean that there are thousands of turbines within a sensor grid layer. This in turn can mean that an energy capture can take a very long time and use an excessive amount of memory. Use with care! As stated above, this layer type is really only intended to be used in those rare circumstances where a visual representation of the wakes is needed.
Once the sensor grid layer has been created it can be enabled/disabled in the same way as a regular site layer. It needs to have access to valid hub height wind resource data like any other turbine layout layer. In order to create rasters showing the wakes from other turbines, an energy capture must be run (at present this functionality does not work with time-series energy captures). Once a frequency-table-based energy capture has been run, it should be possible to right-click on the sensor grid layer and choose Rasterise Turbine Results. This will bring up the dialog box below. The default resolution is taken from the sensor grid layer and it is recommend to be left as default. The current energy capture settings are used to initialise the wind speed and direction ranges. It is recommended to use very limited energy capture settings in order to save time running the energy capture and to save memory and storage space for the rasters. Another way to save space is to only choose the output fields that are of interest.
It is possible to create raster in which the only variation is due to wake effects. This is achieved by going into the energy capture settings and settings the speed-ups scale factor to zero.
The dialog automatically populates with the energy capture settings last used. The resulting rasters have one layer for each wind speed and within each layer, the number of direction steps used in the energy capture calculation.