Guerit L, Métivier F, Devauchelle O, Lajeunesse E, Barrier L
Institut de Physique du Globe de Paris -Sorbonne Paris Cité, Université Paris Diderot, CNRS, UMR7154, 1 rue Jussieu, 75238 Paris Cedex 05, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Aug;90(2):022203. doi: 10.1103/PhysRevE.90.022203. Epub 2014 Aug 13.
When they reach a flat plain, rivers often deposit their sediment load into a cone-shaped structure called alluvial fan. We present a simplified experimental setup that reproduces, in one dimension, basic features of alluvial fans. A mixture of water and glycerol transports and deposits glass beads between two transparent panels separated by a narrow gap. As the beads, which mimic natural sediments, get deposited in this gap, they form an almost one-dimensional fan. At a moderate sediment discharge, the fan grows quasistatically and maintains its slope just above the threshold for sediment transport. The water discharge determines this critical slope. At leading order, the sediment discharge only controls the velocity at which the fan grows. A more detailed analysis reveals a slight curvature of the fan profile, which relates directly to the rate at which sediments are transported.
当河流到达平坦平原时，它们常常将沉积物负载堆积成一种叫做冲积扇的锥形结构。我们展示了一种简化的实验装置，它在一维空间中再现了冲积扇的基本特征。水和甘油的混合物在由狭窄间隙隔开的两块透明板之间输送并沉积玻璃珠。当模拟天然沉积物的珠子在这个间隙中沉积时，它们形成了一个几乎一维的扇体。在中等沉积物流量下，扇体准静态生长，并将其坡度维持在略高于沉积物输送阈值的水平。水流量决定了这个临界坡度。在主导阶次上，沉积物流量仅控制扇体生长的速度。更详细的分析揭示了扇体轮廓的轻微曲率，这与沉积物的输送速率直接相关。
