Overview
Sequences 8 and 9: Downwind Sonics (F,P) and Downwind Sonics Parked
(P)
This test sequence used an upwind, rigid turbine with a 0° cone angle. The wind speed ranged
from 5 m/s to 25 m/s. Yaw angles of 0° to 60° were achieved. The blade tip pitch was 3°. The
rotor rotated at 72 RPM during Sequence 8, but it was parked during Sequence 9. Blade pressure measurements were collected. The five-hole probes were removed and the plugs were installed.
Plastic tape 0.03-mm-thick was used to smooth the interface between the plugs and the blade. The
teeter dampers were replaced with rigid links, and these two channels were flagged as not
applicable by setting the measured values in the data file to –99999.99 Nm. The teeter link load
cell was pre-tensioned to 40,000 N. During post-processing, the probe channels were set to read
-99999.99.
Sonic anemometers were mounted on a strut downwind of the turbine. The strut was mounted to
the T-frame, which was rotated to align the anemometers aft of the 9% and 49% radius locations
at hub height. Because of this configuration, the tunnel balance data are considered invalid.
Sequence 9 was designed to compare the downwind sonic anemometer readings with the upwind
sonic anemometers without interference from the turbine. The rotor was parked with the
instrumented blade at 0° azimuth. All pressure measurements obtained in Sequence 9 are invalid
because sufficient time for temperature stabilization did not occur, thus all associated data values
were flagged as not applicable by setting the measured values in the data file to 0.0000 Pa. This
test is further described in Appendix G.
Data Details
File naming information can be found in the attached Word document "Sequence 8 Filename Key", copied from the Phase VI Test Report.