Author(s): Minakshee Mahananda, Prashanth Reddy Hanmaiahgari

Linked Author(s): Minakshee Mahananda

Keywords: Turbulence, open channel flow, flow development, secondary currents, boundary layer

Abstract: A detailed experimental investigation of lateral variation of turbulent characteristics is carried out in developing and fully developed flow over a fixed rough bed. Experiments are conducted in a rectangular flume with gravel bed and keeping flow aspect ratio below four. In this study, instantaneous 3-D velocities are measured using a Nortek Vectrino plus down-looking ADV. Raw velocity data has been filtered as prescribed in the recent literature. The characteristics of normalized flow velocity, turbulent intensities, Reynolds shear stresses and TKE distribution have been investigated. It is observed that the boundary layer thickness increases along the streamwise distance in the developing flow region and reaches maximum in fully developed flow. On contrary, boundary layer thickness decreases in the lateral direction from the centerline of the channel towards sidewalls in both developing and fully developed flows. Local shear velocities are estimated using the Reynolds shear stress distribution in the intermediate layer. Lateral variation of shear velocity shows decreasing trend in both developing and fully developed flow from the centerline towards sidewalls. Dip phenomenon is observed in both the vertical distribution of normalized streamwise velocity and Reynolds shear stress profiles along the lateral direction in the region adjacent to sidewalls in both the developing and fully developed flow

DOI:

Year: 2017