PARTICLES- FLUID INTERACTIONS IN THE SETTLING VELOCITY OF NATURAL SANDS.

Author's Name: Juan A. García Aragón & Humberto Salinas Tapia
Subject Area: Science and Engineering
Subject Engineering
Section Research Paper

Keyword:

Sediment transport, natural sands, PTV, turbulence, fluid-solid interactions, settling velocity.


Abstract

Experiments with non-uniform natural sands were developed in a suspended sediment transport channel of 22m long and cross section of 1.2x1 m. Using image analysis the settling velocities for different range of particle diameters in the sand mixture were calculated. The Particle Tracking Velocimetry (PTV) method was used. The images of particles illuminated by laser light were captured using the software Looksee. Particle identification and displacement was made using the software AIP that uses analysis by integrated processing. The results show that the settling velocities of particles are affected by fluid velocity and the presence of other particles; the largest particles are more prone to be effected in its settling velocity. A model for the settling velocity of particles in cross flow should include the effect of the fluid velocity. A physical explanation of the phenomena of increasing settling velocity as the particles move away from the sediment supplier is related with the changes in turbulent characteristics of the fluid by other sizes particles.

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