Author(s): Corrado Gisonni; Willi H. Hager
Linked Author(s): Willi H. Hager, Corrado Gisonni
Keywords: Bed form; Dune; Hydraulics; Morphology; River; Sediment Transport
Abstract: Dunes are bed forms larger than ripples known to develop in alluvial rivers for a relatively large grain size, typically above 1 mm. Fully developed dunes may be characterized by the relative dune height, the relative dune length, and the dune steepness. Fields measurements indicate that the dune length may vary between four and eight times of the flow depth, and their height be up to one third of the flow depth. Formulae were proposed within the past years for these parameters, based on the essential dune parameters. The present experimental study aimed to investigate the main hydraulic features of dunes. The test program involved six test series, in which a variety of individual conditions were analyzed. Dune propagation was recorded during the experiments, allowing to estimate the evolution of dune length and height, along with dune celerity, corresponding to variable hydraulic conditions over a wide range of basic parameters.