The rheology of snow in large chute flows
The rheology of snow in large chute flows
复制标题
DOI：
10.1016/j.coldregions.2004.03.006
复制
发表时间：
2004-10-01
影响因子：
4.1
通讯作者：
McElwaine, JN
中科院分区：
文献类型：
--
作者：
Kern, MA;Tiefenbacher, F;McElwaine, JN
测量了沿着长 34 m、宽 2.5 m 的滑槽流下的雪的速度分布和基础剪切力。在进行测量且角度为 32 度的滑槽末端时，流量大致稳定。基础剪切应力的测量证实了近似的动态平衡。使用光电传感器测量速度剖面，结果显示底部有较大的滑移速度、约 50 毫米的剪切层和约 350 毫米的上覆塞状流。速度分布与 Herschel-Bulkley 流变模型（将恒定临界应力与依赖于平均剪切速率的幂律相结合）和 Cross 模型（其中有效粘度在两个极限之间变化）兼容。雷诺数的估计表明流动不是湍流。这些测量结果用于估计能量耗散的分布，并表明能量耗散在底部附近的集中可能会局部融化雪，从而解释在流动的雪崩轨迹底部观察到的冰融化表面。 (C) 2004 Elsevier B.V. 保留所有权利。
The velocity profile and basal shear force were measured for snow flowing down a chute 34 m long and 2.5 m wide. The flows were approximately steady by the end of the chute where measurements were taken and the angle was 32degrees. Measurements of the basal shear stress confirm approximate dynamic balance. The velocity profile was measured using optoelectronic sensors and showed a large slip velocity at the base, a shear layer of around 50 mm and an overlying plug-like flow of about 350 mm. The velocity profile is compatible with both a Herschel-Bulkley rheological model, which combines a constant critical stress with a power law dependence on the mean shear rate, and a Cross model where the effective viscosity varies between two limits. Estimates of the Reynolds number suggest that the flow is not turbulent. The measurements are used to estimate the distribution of energy dissipation and to show that its concentration near the base may locally melt the snow, and thus serve as an explanation for icy melt surfaces observed at the base of flowing avalanche tracks. (C) 2004 Elsevier B.V. All rights reserved.