ABSTRACT
Natural rivers are seldom straight along reaches longer than a few channel widths. The main difference between flow in straight and curved channels is the presence of a centrifugal force in the latter. The centrifugal forces along river bends induce a secondary flow in the transversal direction to the primary longitudinal flow; an effect also referred as helical or spiral motion. This secondary flow causes redistribution of velocities, boundary shear stresses and sediment transport along the bends, shaping the morphology of alluvial curved channels (Blanckaert & Vriend 2003).
