Visualization of Spiral Motion in Curved Open Channels of Large Width

THE difficulty of recording spiral motion in curved open (river) channels and of visualizing the secondary currents at a cross-section of a bend, particularly when the stream is very wide, has led to differing, and sometimes contradictory, conclusions on the behaviour of flow around bends. Indeed, some observations on sand movements around river bends 1 seem to reject the very existence of spiral motion.