TurbSim Overview |
 
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TurbSim Overview |
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This section presents a very brief synopsis of TurbSim, using information sourced directly from the program documentation, reproduced with the permission of NREL. Refer to the NREL TurbSim documentation for further information.
TurbSim is a stochastic, full-field, turbulence simulator primarily for use with InflowWind-based simulation tools. The TurbSim stochastic inflow turbulence tool has been developed to provide a numerical simulation of a full-field flow that contains coherent turbulence structures that reflect the proper spatiotemporal turbulent velocity field relationships seen in instabilities associated with nocturnal boundary layer flows and which are not represented well by the IEC Normal Turbulence Models. Its purpose is to provide the wind turbine designer with the ability to drive design code simulations of advanced turbine designs with simulated inflow turbulence environments that incorporate many of the important fluid dynamic features known to adversely affect turbine aeroelastic response and loading. TurbSim is more efficient than its predecessors in terms of both CPU and memory usage. This software was developed by Neil Kelley and Bonnie Jonkman of NREL.
1.Download the TurbSim program from the TurbSim website or OpenFAST GitHub site. The downloads are supplied as self-extracting ZIP files.
2.Source code is available should you wish to compile the software, but it is more straightforward to use a pre-compiled executable program. You will be seeking a file called TurbSim_x64.exe (or TurbSim_Win32.exe if you are running a 32-bit operating system).
3.Note that the TurbSim website also provides a helpful user guide. This contains useful technical information and ideally you should familiarise yourself with the various wind parameter inputs.
4.Save TurbSim_x64.exe to a convenient location on your hard drive, for example ‘C:\Program Files\NREL\TurbSim\TurbSim_x64.exe’.
The easiest way to run TurbSim is via the Wind Field Generator app, which effectively incorporates TurbSim into the Flexcom environment. This is a helpful tool which acts a user-friendly interface to the TurbSim software which does not have a conventional Window-based GUI of its own. It allows you to run batches of TurbSim wind field simulations to generate all the wind data files which you require to support your design load cases. Several of Flexcom's wind turbine examples, such as Example L04 - IEA 15MW RWT, utilise TurbSim binary wind-field definitions files. With the file extension BTS (denoting Binary TurbSim), these files tend to be very large so they are not supplied with Flexcom as it is not practical to include them in the installation package. Instead you can readily generate the BTS files yourself with the Wind Field Generator app.
Alternatively you can run TurbSim from a command prompt window if you prefer. TurbSim is a DOS-based program and many younger software users may not be familiar with this system which predates Windows. But it is quite straightforward, and you can follow these steps even if you are not experienced with DOS.
1.Open a command prompt window. You can do this by typing CMD into the Windows search box.
2.Note that you can use the command 'cd foldername' to change directory in the command prompt window. The command 'cd..' allows you to move up one directory level. If the file paths contain spaces, you must enclose the entries in quotation marks.
3.Navigate to a location on your computer where some TurbSim input files are located. For Example L04, the command will be something like cd “C:\Users\Public\Documents\Wood\Flexcom\Version 2025.1.2\Example Projects\L - Wind Energy\04 - UMaineVolturnUS-IEA15MW\Data\Wind”. Or you can move in a series of smaller steps, for example (i) cd C:\Users, (ii) cd Public, and so on.
4.If you examine this wind data folder in Explorer, you will notice that it contains a sample IN file, called IECKAI-1NTM-4-60362647-0.in. It uses the following naming convention:
a.IECKAI is the turbulence model, a Kaimal spectrum in this case
b.1NTM is the IEC turbulence type, in this case 1 is the wind turbine class and NTM denotes normal turbulence
c.4 is the wind speed, 4m/s in this case
d.60362647 is a random seed associated with the generated wind profile
e.0 is the wind direction, 0 degrees in this case
5.To generate a binary (BTS) file from an input (IN) file, you type the name of the TurbSim executable, followed by the name of the wind input file. For example, the command might look as follows: “C:\Program Files\NREL\TurbSim\TurbSim_x64.exe” “IECKAI-1NTM-4-60362647-0.in”. This approach will allow you to generate all the required BTS files one by one.
6.If you would like to automatically generate several files simultaneously, you can examine the batch file which is contained in the wind folder (RunTurbsimNew.bat). This can be viewed in any standard text editor and can be saved in text format after you have made your changes.
a.Identify the location of TurbSim on your computer, via the ‘turbsim_exe’ entry
b.Set the number of concurrent runs, via the ‘maxProc’ entry, this should be less than the number of CPUs available on your computer
c.Edit the list of IN files which you wish to process, these are listed under the ‘list of commands’ comment
d.Save the file and close once you are finished
e.Run the batch by typing the name of the batch file into the command window, i.e. type ‘RunTurbsimNew.bat’