资源环境科技发展态势分析平台

The terminal velocity v(t) and preferred orientations of ice particles have been investigated using 3-D-printed analogues sedimenting in glycerine solutions at Reynolds numbers typical of natural ice particles falling in air. Twenty-two different particle geometries were investigated: these included both simple shapes, such as hexagonal plates, and more complex particles, such as bullet rosettes, plate polycrystals, and aggregates. Two widely used prescriptions for ice particle fall speed were tested against the new experimental data, to determine the accuracy of their predictions. We show that for open particles, such as bullet rosettes and aggregates, one of these prescriptions systematically overestimates vt, by as much as 80%.