freeyaw-ojf-wt-tests

This repository is still a work-in-progress (WIP). The documentation is
incomplete at this point and not all of the scripts to reproduce the results are
in the repository yet. Please contact the author for more information.

This repository holds the post-processing utilities that have been used to process wind tunnel measurements performed at the TU Delft Open Jet Facility. A three bladed, downwind, free yawing wind turbine was tested during 2 campaigns: one in February 2012, and a second one in April 2012. These tests took place within the framework of a PhD project at DTU Wind Energy in Denmark (some additional information can be found here).

These wind tunnel test results have been funded by:

• EU FP7 Marie-Curie IAPP grant #230698: Windflower - Aeroelastic tailoring of a passive wind turbine rotor and experiment-based validation of design code
• Dutch NWO Veni Grant #11930: Reconfigurable Floating Wind Farms

The wind tunnel tests have been organized by (job description listed is at the time of the experiment):

• David Robert Verelst, PhD student at DTU Wind Energy
• Jan-Willem van Wingerden, Associate Professor at the TU Delft

The results have been discussed in much more detail in the following publications:

• Numerical and Experimental Results of a Passive Free Yawing Downwind Wind Turbine
• Open Access Wind Tunnel Measurements of a Downwind Free Yawing Wind Turbine

When referring to the this data-set, please cite the above mentioned references.

This Github repository does not include the raw and calibrated result files, but has to be downloaded separately due to its size. The current version of the data set is v2015-11-26 and contains the following:

• data/model/cross-sections (67.3 MB): blade cross section profile coordinates from root to tip (tabulated and plots)
• data/raw (5.5GB): unedited, raw result files
• calibrated/DataFrame (5.4GB): calibrated, unified result files, in pandas.DataFrame HDF5 format
• calibrated/CSV (3.8GB): calibrated, unified result files, in CSV format (plain text)
• database Index of all the measurements, including various labels to distinguish between the different measurement runs (such as blade type, wind speed, etc). Also includes mean, max, min and standard deviations for each run and all channels.
• database/figures (117.2 MB): plots of the calibrated result files, in PNG format
• media/pictures (720.4 MB): pictures of various phases of the experiment

These data files are compressed with 7zip and the archives are split in parts of maximum 1000MB.

Wind turbine aeroelastic description

The aeroelastic description of the wind turbine that was used for this campaign is included under data/model:

• The blade mass properties for all 6 blades are given under data/model/blademassproperties
• The airfoil shapes are given under data/model/S822.dat and data/model/S823.dat
• The full HAWC2 model description is filed under data/model/hawc2, users looking for a single example to run can use data/model/hawc2/htc/ojf_post_example.htc
• Generator torque source code: data/model/hawc2/control/ojf_generator
• Yaw control source code (for simulating a fixed-yaw-free-yaw transition): data/model/hawc2/control/yaw_control
• The control DLLs are under data/model/hawc2/control. Note that the control DLL source can be compiled with the open source compiler Lazarus.

Description of the measurement channels

Channel names as used in the calibrated and unified result files as used in:

• calibrated/DataFrame
• calibrated/CSV

Channel header names:

• time : time stamp [s]
• rpm : rotor speed [rpm]
• yaw_angle : yaw inflow angle [deg]
• tower_strain_fa : tower base for-aft (FA) bending moment in [Nm], based on tower base straing gauges. Calibrated results only available for April campaign.
• tower_strain_ss : tower base side-side (SS) bending moment in [Nm], based on tower base straing gauges. Calibrated results only available for April campaign.
• towertop_acc_fa : acceleration in for-aft direction, measured from an accelerometer placed in the nacelle
• towertop_acc_ss : acceleration in side-side direction, measured from an accelerometer placed in the nacelle
• towertop_acc_z : acceleration in vertical direction, measured from an accelerometer placed in the nacelle
• voltage_filt : voltage measurement
• current_filt : current measurement
• rotor_azimuth : rotor azimuth position, where 180 degrees refers to blade 3 pointing down (in tower shadow)
• duty_cycle : generator dump load setting, where 0 refers to lower generator torque, and 1 refers to a higher generator torque setting.
• power : amount of power being dissipated in the resistance. Note that this excludes the losses in the generator, the PWM module, cabling, and the mechanical losses (bearings). This sensor can not be used for reliable rotor power measurements.
• power2 : not reliable
• sound : not reliable
• sound_gain : not reliable
• hs_trigger :
• hs_trigger_start_end :
• rpm_pulse : rotor speed [rpm] based on the one pulse per revolution measurement
• temperature : wind tunnel temperature [deg C]
• wind_speed : wind speed in wind tunnel [m/s]
• static_p : static pressure in wind tunnel [kPa]
• blade2_root :
• blade2_30pc :
• blade1_root :
• blade1_30pc :
• blade_rpm_pulse : rotor speed [rpm] based on the one pulse per revolution measurement, based on pulse sensor on the wireless blade strain DAQ