Search results for "secondary current"
showing 5 items of 5 documents
Mean flow, secondary currents and bed shear stress at a 180-degree laboratory bend with and without enhanced permeable groins as an Eco-friendly rive…
2022
River restoration aims to apply environmentally-friendly structures for bank protection in meandering rivers to restore their natural habitat. Enhanced Permeable Groin (EPG) is a novel river restoration technique that can improve the fish habitat environment in a river system by creating a series of eco-friendly scour pools. This study reports the results of two groups of 3D velocity measurements in a 180-degree channel bend in cases with and without an EPG for clear water conditions to characterize the mechanisms leading to the primary stages of the scouring phenomenon. The analysis revealed that the presence of an EPG amplified the velocity magnitude in the regions near the tip of the van…
Role of secondary circulation on bank erosion in a large amplitude meandering laboratory channel
2009
This paper reports peculiar results of experimental investigation on the evolution of flow secondary circulation motion along a meander wave. The experiments have been conducted in a large amplitude meandering laboratory channel for two values of the width-to-depth ratio. Attention is focalised on how secondary motion affects the bank shear stress distribution, influencing the bank stability. The analysis essentially highlights that, especially for small width-to-depth ratio, as the channel curvature increases besides the classical central-region secondary circulation cell a counter-rotating circulation cell forms in the outer-bank region. Such counterrotating circulation cell allows to obt…
Prediction of river discharges at confluences based on Entropy theory and surface-velocity measurements
2022
Hydrodynamic features of the confluence zone of large rivers are complicated because of their three-dimensional flow structure. The confluence between the Rio Negro and the Rio Solimões, characterised by black and white waters, respectively, ranks among the largest river junctions on Earth. An Entropy-based investigation was carried out to assess the discharge and analyse the 2D structure of velocity distribution for large river flows relying on monitoring of near-surface velocity only. The estimated flow data where compared with in-situ ADCP data gathered across some transects of the Negro and Solimões rivers during both low and relatively high flow conditions. Results are illustrated thro…