Dossier Sommaire ☆ ☆ Leveed and fingered deposit of a bi-disperse mixture of spherical (white) glass ballotini (75–150 μm) and irregular (brown) carborundum grains (315–350 μm) on a chute inclined at 27° and made of a monolayer of (turquoise) glass ballotini (750–1000 μm). The photo shows an oblique head-on view, with the depth of field used to give an impression of distance; regions far away or close to the camera are out of focus. The flow direction is from top to bottom. Each finger consists of a coarse-rich (brown) levee on either side, lined with an almost pure layer of more mobile fines (white). This relatively low friction channel lining is progressively revealed as the channel flow (speckled in centre) drains down and stops. This flow self-organization significantly enhances the run-out; the formation of fingers and lateral levees prevents the flow from spreading laterally while the fines lining in the channel reduces basal friction (video). For further details, see J.M.N.T. Gray, this issue, pp. 73–85. Leveed and fingered deposit of a bi-disperse mixture of spherical (white) glass ballotini (75–150 μm) and irregular (brown) carborundum grains (315–350 μm) on a chute inclined at 27° and made of a monolayer of (turquoise) glass ballotini (750–1000 μm). The photo shows an oblique head-on view, with the depth of field used to give an impression of distance; regions far away or close to the camera are out of focus. The flow direction is from top to bottom. Each finger consists of a coarse-rich (brown) levee on either side, lined with an almost pure layer of more mobile fines (white). This relatively low friction channel lining is progressively revealed as the channel flow (speckled in centre) drains down and stops. This flow self-organization significantly enhances the run-out; the formation of fingers and lateral levees prevents the flow from spreading laterally while the fines lining in the channel reduces basal friction (video). For further details, see J.M.N.T. Gray, this issue, pp. 73–85. Video 1
Titel:
Dossier Sommaire ☆ ☆ Leveed and fingered deposit of a bi-disperse mixture of spherical (white) glass ballotini (75–150 μm) and irregular (brown) carborundum grains (315–350 μm) on a chute inclined at 27° and made of a monolayer of (turquoise) glass ballotini (750–1000 μm). The photo shows an oblique head-on view, with the depth of field used to give an impression of distance; regions far away or close to the camera are out of focus. The flow direction is from top to bottom. Each finger consists of a coarse-rich (brown) levee on either side, lined with an almost pure layer of more mobile fines (white). This relatively low friction channel lining is progressively revealed as the channel flow (speckled in centre) drains down and stops. This flow self-organization significantly enhances the run-out; the formation of fingers and lateral levees prevents the flow from spreading laterally while the fines lining in the channel reduces basal friction (video). For further details, see J.M.N.T. Gray, this issue, pp. 73–85. Leveed and fingered deposit of a bi-disperse mixture of spherical (white) glass ballotini (75–150 μm) and irregular (brown) carborundum grains (315–350 μm) on a chute inclined at 27° and made of a monolayer of (turquoise) glass ballotini (750–1000 μm). The photo shows an oblique head-on view, with the depth of field used to give an impression of distance; regions far away or close to the camera are out of focus. The flow direction is from top to bottom. Each finger consists of a coarse-rich (brown) levee on either side, lined with an almost pure layer of more mobile fines (white). This relatively low friction channel lining is progressively revealed as the channel flow (speckled in centre) drains down and stops. This flow self-organization significantly enhances the run-out; the formation of fingers and lateral levees prevents the flow from spreading laterally while the fines lining in the channel reduces basal friction (video). For further details, see J.M.N.T. Gray, this issue, pp. 73–85. Video 1