The OC3-Hywind system is an offshore floating wind turbine system. We have been modeling offshore floating wind turbines using an extension to FAST that we call HydroDyn. For floating platforms, the hydrodynamics and mooring system models are well documented in the in my recent Wind Energy journal article and in my PhD thesis-turned NREL report: nrel.gov/docs/fy08osti/41958.pdf.
The offshore features are not available in FAST v6.01. In fact, we haven’t yet officially released the offshore version of FAST. For one reason, this is because we haven’t had the time to fully document it yet. We also plan to improve the interface to HydroDyn before we officially release it. That said, we provide the code to most anyone who requests it. We have sent the code to many users already, so, it is well tested. I typically suggest, howerver, that anyone who uses it gain a bit of experience modeling land-based wind turbines with FAST before moving on to modeling offshore turbines, which are much more complicated to analyze.
We have developed the new offshore features in a yet-to-be released alpha version of FAST known as v6.02c-jmj. Because this is an alpha version, this means that the new features are not yet documented in the FAST User’s Guide. Once one is already familiar with FAST and AeroDyn, though, it is fairly straightforward to learn how to use the new offshore features. FAST v6.02c-jmj can downloaded from: wind.nrel.gov/designcodes/simula … 2c-jmj.exe. We plan to officially release updated versions of these codes in 2010.
There are several models you can use to start playing with the new offshore features. In addition to the 17 sample wind turbine models (all onshore) provided in the archive of the standard version of FAST, I’ve put five models of the NREL 5-MW baseline wind turbine here: wind.nrel.gov/public/jjonkman/NR … rBsline5MW. These models include, the (1) onshore version of the 5-MW turbine, (2) the 5-MW turbine installed on a fixed-bottom monopile with rigid foundation in 20m of water, (3) the 5-MW turbine installed on the floating ITI Energy barge (the floating platform I analyzed in my PhD project), (4) the 5-MW turbine installed on a floating Tension Leg Platform, and (5) the 5-MW turbine installed on a floating spar-buoy (based on the OC3 project’s modifications to the Hywind concept). The archive for the model of the onshore version of the NREL 5-MW wind turbine includes a report that documents the turbine.
Each of these models contain a torque and pitch controller in GH Bladed-style DLL format. These controllers require FAST’s interface to GH Bladed-style DLLs, which is not a default option in the current version of FAST. You can find a version of FAST with this interface here: wind.nrel.gov/public/jjonkman/FA … erface.exe. Or if you’re adventurous, you can recompile FAST using the guidance found in the FAST User’s Guide.
All of the new offshore-related (hydrodynamic and mooring system) inputs are contained in the updated platform input files.
By the way: The website found at wind.nrel.gov/public/jjonkman/ does not contain source code for FAST. This website contains various compiled versions of FAST and sample models that I have given to users based on their request.