Two-layer gas-particle currents are investigated using heated (~70 °C) aerating powder (sub-45 micron diameter silica beads) in a flume with a porous base (Figure 1). These flows provide a unique method for observing the interface between a dense granular underflow and a turbulent dilute over-lying flow, as envisaged to exist within many pyroclastic density currents (PDCs), with the aeration effective in overcoming scaling issues related to rapid pore pressure diffusion in thin flows under laboratory conditions (Rowley et al. 2014). Sediment supply from a hopper enables sustained currents to form. High speed video at 1024 x 256 pixels is used to record the flow behaviour through a transparent perspex sidewall.
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机译：使用加热的（〜70°C）充气粉末（直径小于45微米的二氧化硅珠）在带有多孔基底的水槽中研究了两层气体颗粒电流（图1）。这些流动提供了一种独特的方法，可以观察到致密的颗粒状底流和湍流的稀薄上覆流之间的界面，如设想在许多火山碎屑密度流（PDC）中存在的那样，通气有效地解决了与快速孔隙压力有关的结垢问题在实验室条件下稀薄流中的扩散（Rowley等人，2014）。来自料斗的沉积物供应使持续的电流形成。 1024 x 256像素的高速视频用于记录通过透明有机玻璃侧壁的流动行为。
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