TURBULENCE IN HURRICANE-GENERATED COASTAL CURRENTS

Abstract

Wind and current meter records taken during the passage of a hurricane were subjected to time series analysis Filtering techniques isolated the speed fluctuations m the 10-60 CPH frequency band These turbulent fluctuations proved to follow the Gaussian distribution for both wind and current With the passage of the storm front the turbulence intensity of the wind actually decreased, while, on the other hand, the turbulence intensity of the current rose to extremely large values, even exceeding 27 percent of the mean flow speed Three phases of the storm were examined separately, and the energy density of the wind varied with the -1 power of the frequency in all phases With respect to the energy density of the current, a -1 power dependency on the frequency was approximated by the first two phases, whereas m the third phase, which was the most intense, the energy density varied approximately as the -0 5 power of the frequency The characteristics of the spectra indicate that there is little direct transfer of energy from the wind to the current m the frequency range studied Energy is passing into the 10-60 CPH band of the current from still lower frequencies.