6. Review on Hydraulics of Meandering Rivers

A meander is a bend in a sinuous watercourse or river. It consists of a series of turns with curvatures in alternate directions which are connected at the points of inflection or by short straight crossings (Dey). Scientists and researchers are studying the hydrodynamics, morphology, bed topography, etc. of meandering rivers for a very long time. The details of secondary flow become an integral part for some researchers while studying meandering rivers. The role of the centre region cell and the presence of the outer bank cell have also been investigated by many researchers and experts. The centre region cell or helical motion occurs due to unequal forces between centrifugal force and pressure force with flow near the surface directed towards the outer bank and that near the bed directed towards the inner bank. Many of them also tried to find the relation between outer bank circulation cell and bank shear stresses and how it affects bank erosion. Researchers and experts have worked to find out various parameters like mean flow, Reynolds shear stress, turbulent kinetic energy (TKE), etc. and their interactions in meander bends. A lot of field and laboratory experiments have been carried out with different conditions to understand the behaviour of meandering rivers.