Turbulence Characteristics of Flow over Smooth and Rough Beds

Abstract

Experimental study on turbulence measurements in an open channel with smooth and rough beds using acoustic doppler velocimeter (ADV) has been carried out in the present study. Measured velocity distribution along the depth on smooth and rough beds for different discharges and bed slopes is in good agreement with logarithmic law. The turbulence intensities were more near the bed and less near the water surface. Existing equations for turbulence intensities over-predict the turbulence intensities; thus, new equations are proposed in this study to predict the turbulence intensities. Turbulent kinetic energy decreases from bed to the water surface. Existing equations for distribution of kinetic energy along depth over-predict the turbulent kinetic energy; therefore, new equations are proposed to predict the turbulent kinetic energy for flow on rough and smooth beds.

Keywords: Open channel, velocity distribution, turbulence, rough bed, smooth bed, ADV