Kahuku kite wind study. II. Kahuku foothills

Technical Report · Wed Sep 01 04:00:00 EDT 1982

OSTI ID:6547861

Daniels, P A; Oshiro, N E

In a test to compare the instruments, eight kites were flown in a close pattern. The test did not reveal calibration bias among the kite heads and the anemometers. Between 23 to 28 April 1981, a ridge was surveyed where a number of wind turbines are planned. The kites were flown continuously for 36 hours after which the trade winds disappeared. The kite winds were compared with those measured at two high meteorological towers on the ridge. Kites were flown at 120 ft and 240 ft for two periods during May to June 1981 close to the Kahuku Opana anemometer site where wind instruments have been maintained for over five years. Considerably lower winds during late night-early morning hours during the second period as compared with the first stemmed from a land breeze component opposing the prevailing trades. The relatively large 42 to 120 ft speed gradient at the site is partly attributable to trees upwind. Four methods to estimate long term wind speeds were tested. One is based on long term statistics and hourly vertical gradients of speed observed during the survey; the other three use simultaneously-collected hourly mean winds at the kite levels and at 42 ft. Of these estimates, those based on linear regression and on statistical parameters developed from the survey period are close to the gradient estimate. Kites were flown continuously for six days at 120 and 240 ft above a potential wind mill site. Field calibrations and subsequent software calibrations are improved. At the site, trade winds prevailed and showed some unexpected features. During an August and September 1981 survey of three potential wind turbine ridges, the kite heads worked reasonably well. However, substantial design changes are recommended. Evidence of a vortex created by morning solar heating was found along exposed ridge slopes upwind of some of the sites. Only marginally-useful winds were estimated for the eastern-most ridge during trades.

• Research Organization: Hawaii Univ., Honolulu (USA). Dept. of Meteorology
• DOE Contract Number: FG03-77ET20184
• OSTI ID: 6547861
• Report Number(s): UHMET-82-02; ON: DE83006402
• Country of Publication: United States
• Language: English

Related Subjects

17 WIND ENERGY
170604* -- Wind Energy Engineering-- Site Characteristics
ANEMOMETERS
CALIBRATION
DAILY VARIATIONS
DATA
DIMENSIONS
EXPERIMENTAL DATA
FEDERAL REGION IX
HAWAII
HEIGHT
INFORMATION
MEASURING INSTRUMENTS
MONITORING
NORTH AMERICA
NUMERICAL DATA
ORIENTATION
SITE SURVEYS
SPECTRA
USA
VARIATIONS
VELOCITY
WIND