Velocity Distribution and the Moments of Turbulent Flow over a Sand-Gravel Mixture Bed

The current study performed the laboratory flume to examine the velocity distribution and the velocity moments of turbulent flow over a sand-gravel mixture bed. The 3D instantaneous velocity data of water is collected by using acoustic doppler velocimeter (ADV) at the test section which will provide an important data related to the flow turbulence. The parameters of turbulence measured that the lower value of longitudinal velocity (velocity along flow direction) is observed close to the bed surface and increases with the flow depth. The lower magnitude of von Karman constant is achived than the universal value. The damping of Reynolds shear stress observed close to the boundary wall indicating lower exchange of flow energy towards the boundary and vice versa. The sand-gravel bed influenced the turbulence intensities with higher magnitude in the streamwise than those in vertical direction. The velocity moments which shows the structure function of fluctuating components of velocity, has been analyzed. The present study also analysed the flow anisotropy, and the flatness factor in the flow.