Evaluation of the saltation process of bed materials by video imaging under altered bed roughness

Auteur(s) et Affiliation(s)



Description :
A series of flume experiments are carried out to study the saltation of individual sand particles of different sizes over rough beds under different flow conditions. A 3-D acoustic Doppler velocimeter is used to record the fluid velocity components; subsequently, under different flow conditions, the images of released sand particles are recorded using high-speed video imaging technique. Systematic analysis is made with regard to the forces acting on the grains and the variation of their magnitudes along the saltation trajectories of the grains. Relations between the saltation parameters, flow intensity and bed roughness are developed. The distributions of the angle of orientations during a single saltation follows almost a Gaussian distribution. The shape of the Gaussian distribution depends on the particle size and bed roughness. Particle collisions with rough beds and the resulting coefficients of restitution are also discussed. A theoretical framework is developed to compute the mean particle velocity considering the spin in the energy balance equation.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 12, p. 1339-1353, nombre de pages : 15, Références bibliographiques : 1 p.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley