Turbulence integral scale and fluctuation wind speed spectrum of typhoon:an analysis based on field measurements

In this paper,the fluctuation characteristics of turbulence integral scale and wind speed spectra of near ground typhoon are studied based on the four sets of long time record of wind speed and wind direction during the passages of typhoon.Firstly,several calculation methods for turbulence integral scale are presented.Secondly,the variation of turbulence integral scale during the passage of typhoon,as well as the stabilization of the calculation methods are investigated.Then,the longitudinal fluctuation wind speed spectra are calculated and the comparison to the empirical spectra,such as the Von-karman spectrum,the Davenport spectrum,the Simiu spectrum and Harris spectrum,are implemented.The best one fitting to the field measurements is recommended.Finally,the lateral wind spectra are calculated,and the comparison to the spectrum derived from longitudinal wind spectrum based on isotropic turbulence theory is performed.