Abstract:
The development of ridges on the unreinforced bottom of a water course has been the subject of many studies owing to the large number of practical problems in which the characteristics of ridges must be evaluated from the known hydrodynamic characteristics of the flow. There are several theories as to the origin of the ridges. But calculations for a given flow based on different theories produce considerably different results and do not give satisfactory results for real flows. Our experimental investigation has proved that in flows with Fr < 1 there exists a correlation between the type of flow, the characteristics of the ridges, and the characteristics of gravity waves that are stationary relative to the bottom. In an open flow of water, bottom ridges are generated by resonant gravity-capillary waves. The lowest phase velocity of the waves in the deep water for σ = 74 dyn/cm2 is 23.1 cm/sec.