Transient wave activity in snow avalanches is controlled by entrainment and topography
Transient wave activity in snow avalanches is controlled by entrainment and topography
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DOI：
10.1038/s43247-023-01157-x
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发表时间：
2024-02
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通讯作者：
Xingyue Li;B. Sovilla;John Mark Nicholas Timm Gray;J. Gaume
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作者：
Xingyue Li;B. Sovilla;John Mark Nicholas Timm Gray;J. Gaume
在地球和其他星球的雪崩中，海浪无处不在。波浪的动态性质使其在泥石流、浑浊流、熔岩流和雪崩等地质灾害中具有危险性。在理想化的假设下，人们利用理论和数值方法对颗粒波进行了广泛的研究。然而，现实中复杂情况下的波的机制仍然是无形的，因为在真实地形上捕捉复杂的颗粒波是出了名的困难。在这里，我们利用最近发展的欧拉-拉格朗日混合数值格式和弹塑性本构模型来研究雪崩波所涉及的过程，包括侵蚀、沉积和由地形不规则性引起的流动不稳定。这使我们能够自然地模拟真实地形上单个大规模雪崩中的滚波、侵蚀-沉积波及其过渡。模拟的波特征与不同雷达技术获得的现场数据具有较好的一致性。在无量纲分析的基础上，波浪力学不仅受弗劳德数和局部地形的控制，而且还受控制卷吸倾向的波的质量控制。这项研究为雪崩的波动机制提供了新的见解，并为探索颗粒运动中的瞬变波提供了一条新的、有前途的途径。
Waves are omnipresent in avalanches on Earth and other planets. The dynamic nature of waves makes them dangerous in geological hazards such as debris flows, turbidity currents, lava flows, and snow avalanches. Extensive research on granular waves has been carried out by using theoretical and numerical approaches with idealized assumptions. However, the mechanism of waves in realistic complex situations remains intangible, as it is notoriously difficult to capture complex granular waves on real terrain. Here, we leverage a recently developed hybrid Eulerian-Lagrangian numerical scheme and an elastoplastic constitutive model to investigate the processes involved in waves of snow avalanches, including erosion, deposition, and flow instability induced by terrain irregularity. This enables us to naturally simulate roll-waves, erosion-deposition waves, and their transitions in a single large-scale snow avalanche on real terrain. Simulated wave features show satisfactory consistency with field data obtained with different radar technologies. Based on a dimensionless analysis, the wave mechanics is not only controlled by the Froude number and local topography but also by the mass of the wave which governs the entrainment propensity. This study offers new insights into wave mechanisms of snow avalanches and provides a novel and promising pathway for exploring transient waves in granular mass movements.