Estimates of Turbulence Intensity and Power Density of an Asymmetric Tidal Current under Wind Forcing Variability

Abstract

A high-frequency (1.2 MHz) four-beam Acoustic Doppler Current Profiler moored on the seabed has been used for direct turbulence measurements in a tidal channel. Five tidal cycles covering calm and storm periods are selected from the measurements. The effect of the tidal cycle asymmetry and the wind forcing variability on the turbulence intensity, Reynolds stresses, and the current energy characteristics is estimated. It is shown that the power density of the tidal flow is twice as low during the storm period than during the calm period. Wave filtering in calculating Reynolds stresses made it possible to estimate the contribution of small-scale turbulence to its intensity.