Barton John M H, Buchberger Steven G
Department of Civil and Environmental Engineering, University of Cincinnati, P.O. Box 210071, Cincinnati, Ohio 45221-0071, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Jul;68(1 Pt 1):011303. doi: 10.1103/PhysRevE.68.011303. Epub 2003 Jul 18.
The underwater geometry of small sand piles is relevant to the removal of noncolloidal sediment by filtration. The critical size range for clogging occurs when noncolloidal particles are about one-tenth the diameter of the media grains. No previous experimental work has examined the formation of sand piles at this scale. Sand pile formation was investigated on small platforms (roughened spheres, flat surfaces, and irregular stones) in the critical size range for clogging. The size of sand piles formed on platforms of irregular crushed stone increases with sand grain diameter. This did not occur for spherical media. Further, this observation contrasts with previous measurements of the angle of repose, which showed a weak decrease with sand grain size. A geometric model for small piles is presented to account for the increase in size of the sand pile as a function of grain size and platform shape.
小型沙堆的水下几何形状与通过过滤去除非胶体沉积物有关。当非胶体颗粒直径约为介质颗粒直径的十分之一时，就会出现堵塞的临界尺寸范围。以前没有实验工作研究过这种规模下沙堆的形成。在堵塞的临界尺寸范围内，在小型平台（粗糙球体、平面和不规则石块）上研究了沙堆的形成。在不规则碎石平台上形成的沙堆尺寸随沙粒直径增大。球形介质则未出现这种情况。此外，这一观察结果与之前对休止角的测量结果形成对比，之前的测量结果显示休止角随沙粒尺寸略有减小。本文提出了一个小型沙堆的几何模型，以解释沙堆尺寸随颗粒尺寸和平台形状的增加情况。
