Rapid shallow granular free-surface flows develop in a wide range of industrial and geophysical flows, ranging from rotating kilns and blenders to rock-falls, snow slab-avalanches and debris-flows. Within these flows, grains of different sizes often separate out into inversely graded layers, with the large particles on top of the fines, by a process called kinetic sieving. In this paper, a rece...

Stilling basins are designed to reduce the high kinetic energy of supercritical flow in a downstream spillway. The USBR II stilling basin is distinguished by chute blocks fixed at upstream end and dented sill end, allowing for effective dissipation excess energy. This research investigates effect chute-block geometry on hydraulic performance basin. Six modified chute-blocks with identical dimen...

For overflow weirs and embankments, the stepped chute profile may increase the rate of energy dissipation on the waterway. Herein four different stepped chute configurations were tested with a focus on the cavity flow processes, flow aeration and energy dissipation performances. Detailed flow visualisations and air-water flow measurements were conducted for all configurations. The results highl...

Submitted for the MAR09 Meeting of The American Physical Society Constitutive relations in dense granular flows JOHN DROZD, COLIN DENNISTON, University of Western Ontario — We use simulations to investigate constitutive relations in dry granular flow. Our system is comprised of monoand poly-disperse sets of spherical grains falling down a vertical chute under the influence of gravity. We observ...

– Inelastic grains in a flow under gravitation tend to collapse into states in which the relative normal velocities of two neighboring grains is zero. If the time scale for this gravitational collapse is shorter than inverse strain rates in the flow, we propose that this collapse will lead to the formation of “granular eddies”, large scale condensed structures of particles moving coherently wit...

In the material transfer area, belt is exposed to considerable damage, energy of falling lost, and there significant dust noise. One most common causes failure chute blockage, when flow in free fall or loading zone disturbed by oversized rock parts other objects, e.g., bolts. The a single point may cause entire transport route be excluded from work associated with costly breakdowns. For this re...

Pine litter fall data, mainly needle litter, were available for 64 plots in a transect from the Arctic Circle in Fennoscandia (41 plots) to southern Spain (22 further plots in continental Europe) and one in the American Midwest). Data originated from a total of eight pine species. Regressions were calculated mainly for needle litter fall and to some extent for total litter fall. We obtained a h...

Stretchable woven chute is a safe device for falling humans from multi-story buildings in emergencies. During the fall, the elastomeric property of the fabric, in the weft direction, causes radial forces towards the human body inside .These radial forces lead to frictional forces between the chute and the body. The falling man can reduce the falling speed by exerting outward forces via stretchi...