How to use WindSIM¶

WindSIM is a software for performing CFD calculations. Some projects demands a more accuracy in the analisys. Sometimes the available satélite data or thirdparty long term measurements are leading to a high uncertainty, speccialy when the in situ measurements are not in agréments with these time-series ( ex.: poor correlation with era5, disagreements between ERA5 and Vórtex with few data poins with measruements to confirm which is best). To run the WinSIM, first its necessarie to have a .GWS file, which contains terrain and roughness data. Then, the configurations for the actual simulation starts.

Organizing the files¶

For the first WindSIM Project create folder in :

WindSIM/D:/WindSIM projects

Determining Domain Size¶

Before creating the GWS file to run WindSIM , it makes a smooth workflow to determine the domain of interest first. By doing this beforehand, it keeps you from copying ans pasting repeated times between diferente Windows, and thus reduces the possibility of picking the wrong information.

There is a WindSIM best practices publication recommending at least 1 km between any point of interest (e.g., MM or WTG locations) and the boundaries of the refinement area, if a refinement area is used. It also recommends a 10 km buffer between the refinement area boundaries and the outer domain. The publication can be found here (XX).

To keep it simple and trackble, determine the coordinate of the domain internal and external boundaries inside windpro

Open the WindPRO project and identify the points of interest that are farthest from the center of the project. Find the northernmost, southernmost, easternmost and westernmost points (whether they are WTGs, meteorological masts or any other relevant location). These points will define the minimum extent of the refinement area.
Create controls points with these locations adding at least 1 km in each direction to define the refinement boundaries. After that you should have 4 or 2, control points, the importante thing is that define a box.
Finally, create the outer domain by adding a 10 km buffer around the refinement area. Do this by creating other control points.
To keep things organized, create a layer groug (e.g: CFD domain/CFD grid/Coordinates - CFD.. etc) to add the vértices of the domains.
Now, create a poligon with the área of interest:
select the poinst fot the outer domain and export as kml format.
Open the control point locations in google Earth
Draw a poligon conecting the points
Export the created poligon to the Project directory folder " Project/WindSIM..."

Creating the GWS file¶

The next steps are inside Global Mapper. This is a GIS software used in our methodology to create the GWS files. These GWS files are (...).

Go to Open file data, locate and open the poligon área kml export
Go to files --> download/topography/online maps...
Choose NASADEN (or other if you wish) and ... There are some options to determine the area do be downloaded. The step done previously with the google Earth export cames now. So, click the button "draw box" and use the polygon to select the Project área. There is no need to be precise. select it with some margin, but never smaller.
Click "conect"
Make sure the coordinate system is correct. Click the tool figure to acess configuration options.
Go to projectionsand change it to the correct coordinate system ( the one begin used, probably UTM) and click OK.

Now the data has downloaded, check for negative values within the DTM:

Double click the topodata layer
Go to Change Elevation Values and if there is a negative value inside the "minimum valid elevation" box. If there is, change it to zero and click Apply.

With the terrain elevation data properly treated, the second part of the gws file generation is to add the roughness information on the location:

Inside Windpro, check the roughness data, if it existis already. It should cover the complete extent of the outer domain. If there is no data yet, or if the downloaded data covers a smaller área, re-download it.
With the roughness object window open, look for convert and change the extension of the data to .map.
With the .map file ready, go to global mapper and open it there.
Now the tricky part:
Go to the windpro Project with the roughness layer on and look for a spot on the land that you can easialy indentify on global mapper too.
Zoom in and observe the values registered for the roughness
- Place the pointer on one of the arrows and look for the roughness class information (LEFT | RIGHT) values for that location. Take note.
- Go to global mapper and double click at the roughness data layer
- At the first tab that opened (Labels/Rotulo) change from : "não usar um valor de atributo" para " Usar valor de atrivuto selecionado
- Chosse ROUGH_L or ROUGH_R
- Then, go to "elevation" tab and choose the same ROUGH_X at both drop down lists.
- Click Aply.
- Now, zoom in at the same spot identidied on windpro. and check ih the new values of roughness correspond do the ones in windpro.
- Have in mind that the windpro values have diferente quantities. the onw in windpro is roughness class values, and the one in global mapper is a distance measure, in m.
- EX: 3 roughness class == 0.4 m
- If the choosen ROUGH_X don't correspond do the values in windpro, try Rough_Y. It should work.
- Right click on the roughness data layer --> analise --> GRADE --> OK
- A new layer (blue layer) should appear

Now, both data sources are prepared. But still need to be United and then exported. To complete the generation of the gws file:

Click on Files and look for export --> export elevation grid format
Choose WindSIM GWS Roughness/Elevation File
Click ok on this new box
go to "export boundaries" tab and "draw a box"
Select with some margim, the área of interest and click ok
Now, attention:
the first window opened asks to select the layer which contains the elevation data.
The second, asks for the roughness layer data.
Save the GWS file at the Project directory.

In WindSIM...¶

First create windsim new Project You will have to already import a a gws file, but it can add after creating the Project too, no problem. Find out this one if you choose to open gws later :)

make sure you already save it in ...

You will see modules on the top of the windsim window: Terrain - WindFields - Objects - Results - Wind Resources - Energy

Observe that once you imported the gws file the terrain extension section on the left window tab, is filled already.

X range Y range and projection have to be filled, if they are not done automatically

First thing you have to do now is determine the GRID in the following sections of the left window tab.

Constructing the gridd (very importante step, I might add)¶

For the grid construction have in mind that to know the best configurtion its required to performe some tests, with at least 3 grids, this is called Grid independency Study.

Refinement área

Horiontal griding

Horizontal reoslution

.

Setting up the calculation model¶

Calibrating the Wind Fields¶

The velocity information generated by the CFD model is not directly usable. It must first be scaled using a representative wind time series. This is done by importing a TWS (Time Series) file. Once the CFD simulation is finished, the Wind Fields tab should display a green check mark, indicating that the simulation completed successfully. The next step is to import the TWS file through the Objects tab.

Attention: WindSIM has a limit on the size of the time series that can be imported. If the file is too large, the import will fail and WindSIM will return an error.

To create the TWS File do the following:

1. Export the desired **Meteo Object** (ERA5, MCP, adjusted ERA5, or any other reference time series) from WindPRO.

2. Navigate to: Z:\\VENTO\\3. Softwares\\19. Python\\Python\_Code\\Final\\CFD\_TWS\_File

3. Open the Python script.

4. Update the coordinates of the measurement point (Meteo Object).

5. Run the script.

6. A .tws file will be generated.

1. Open the **Objects** tab.

2. Under **Park Layouts**, select **Meteorological Data** (third icon on the right).

3. Import the generated .tws file.