Combined effects of wave and current in free surface turbulent flow

Abstract

The present work is focused on the evaluation of combined wave-current interaction through an experimental study carried out in a laboratory flume. The three-dimensional velocity field was measured by an acoustic Doppler velocimeter (ADV). The results highlight the modifications in the mean velocities, turbulence intensities, and Reynolds shear stress due to the superposition of waves of different frequencies on current-only flow. This study also investigates the dominant turbulent bursting event that contributes to the Reynolds shear stress. The results show that at regions near as well as far from the bed, the contributions to the total shear stress from ejection and sweep are dominant. The mean time interval of the occurrence of bursting events is obtained from the measurements of the fractional contributions to the total shear stress. As the frequency of the surface wave in unidirectional current is changed, change in turbulence statistics is recorded which may affect the local sediment mobility in the coastal region.