Image processing for the study of bedload transport of two-size spherical particles in a supercritical flow

• Published in: Experiments in fluids 2010-11, Vol.49 (5), p.1095-1107
• Main Authors: Hergault, Virginie, Frey, Philippe, Métivier, François, Barat, Cécile, Ducottet, Christophe, Böhm, Tobias, Ancey, Christophe
• Format: Article
• Language: English
• Subjects: Beads; Computer Science; Earth sciences; Earth, ocean, space; Engineering; Engineering Fluid Dynamics; Engineering Sciences; Engineering Thermodynamics; Exact sciences and technology; Fluid dynamics; Fluid flow; Fluid mechanics; Fluid- and Aerodynamics; Fluids mechanics; Heat and Mass Transfer; Hydrology; Hydrology. Hydrogeology; Image processing; Marine and continental quaternary; Mechanics; Physics; Research Article; Rest; Signal and Image processing; Supercritical flow; Surficial geology; Turbulence; Turbulent flow
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/s00348-010-0856-6

Bedload sediment transport of two-size coarse spherical particle mixtures in a turbulent supercritical flow was analyzed with image and particle tracking velocimetry algorithms in a two-dimensional flume. The image processing procedure is entirely presented. Experimental results, including the size, the position, the trajectory, the state of movement (rest, rolling, and saltation), and the neighborhood configuration of each bead, were compared with a previous one-size experiment. Analysis of the solid discharge along the vertical displayed only one peak of rolling in the two-size bed, whereas three peaks of rolling appeared in the one-size case due to a larger collective motion. The same contrast is evidenced in spatio-temporal diagrams where the two-size mixtures are characterized by the predominance of saltation and a smaller number of transitions between rest and rolling. The segregation of fine particles in a bed formed by larger particles was analyzed taking into account the neighborhood configurations.