FIELD MEASUREMENT OF TYPHOON WIND CHARACTERISTICS IN OFFSHORE MOUNTAINOUS AREAS

Based on the field measured data during Typhoon "Haitang" and "Nesat" in 2017, the variation of mean wind speeds, turbulence intensities, and surface roughness exponents in coastal mountains were studied in the case of strong wind samples (10 min mean wind speed ≥10 m/s). And the variations of wind profile and turbulence profile in different wind speed intervals were also analyzed. The results show that the time history of wind speed during the two typhoons appears a double "M" type with four peaks. The time history of the mean wind directions changes about 260° during the two typhoons. Turbulence intensity fluctuates from 0.15 to 0.34 at the height of 10 m, which increases with the increasing of surface roughness exponents. The wind profile and turbulence profile during typhoons accord with the power law of Standard GB 50009−2012. Meanwhile, the power laws of wind profile measured by the two wind towers during typhoons are 0.15 and 0.14, respectively, which are close to the value of the exposure category B specified in Standard GB 50009−2012. The power laws of wind profile during typhoons are higher than the results during monsoon. And, the power laws of the turbulence intensity profiles during typhoons are larger than those stipulated in Standard GB 50009−2012. The results of this paper can provide reference for the design of engineering structures during typhoons in offshore mountainous areas.