Experimental study on near-bed flow turbulence of sinuous channel with downward seepage

Abstract

The presence of a small seepage velocity in streams and rivers induces transfer of mass and momentum near the sediment boundary, causing bank failure and instability of hydraulic structures. This experimental study is intended to report near-bed hydrodynamics and morphological characteristics under the impact of downward seepage. A laboratory investigation was conducted in a sinuous rectangular alluvial channel with rigid sides and movable uniform sand bed. From the distribution of Reynolds shear stress (RSS), the transverse or radial motion of the sediment across the bend was identified. High values of RSS in the outer region relate to higher momentum flux, eroding the outer bend. The contribution probability of ejection and sweep events are highest in the bend region. For seepage, the contribution probability of the events has increased. Moreover, the altered flow with seepage affected the transport of sediment and caused noticeable modifications along the channel bed. With seepage, the erosion rate has been enhanced along the outer bend of the channel.

Flow behaviour in a multi‐layered vegetated floodplain region of a compound channel

“…It was an improved version of quadrant analysis (Kline et al, 1967), where it also considers the transverse velocity fluctuations as opposed to that in quadrant analysis. This transverse velocity ( ) plays a key role in obstructed flow, sinuous, and braided river (Keshavarzi et al, 2014; Khan et al, 2022; Taye & Kumar, 2021). Keylock et al (2014) used the octant analysis to study bed load sediment entrainment.…”

Effect of Mean Velocity-to-Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

“…Qin et al [18] investigated the secondary flow effect on bed topography variations and cohesive sediment transport in Yangtze's meandering path. Taye and Kumar [19] conducted an experimental study of bed morphological characteristics in a sinuous rectangular channel under the influence of downward seepage. They used the Reynolds shear stress distribution to determine the sediment's radial motion along this meandering channel.…”