Collaborative research: Mapping bed forces to granular flow properties

滑坡、罗克瀑布、火山爆发、泥浆、岩石和碎片的快速流动、雪崩和充满沉积物的洪水都是致命的、代价高昂的自然灾害。它们也被称为自然颗粒流。这些事件是危险的，部分原因是它们的快速和强大的性质，但也因为用于预测和减轻其影响的模型仍然不完善。看似简单的问题仍然对科学家和工程师提出了重大挑战，例如：这些事件会有多大？他们要走多远？哪些基础设施存在风险？这个项目将研究颗粒流如何与它们流过的东西相互作用，特别关注冲击力。研究结果将有助于制定更准确的模型颗粒流的流动性和危害。将开展推广活动，突出受控实验室实验对研究自然灾害的兴奋和效用。研究人员将与教育学专家合作开发这些项目，在4 - 8年级的教室中实施，并将其纳入教师年度研讨会，并作为两个科学博物馆的互动探索站。 这个项目的首要目标是提高我们的理解的力量赋予颗粒流在他们的床上。这项工作的动机是假设，许多地貌过程和相关的危害是由最大的床力，而不是平均力。这项研究将建立在颗粒力学的进步，并应用一种新的混合离散元建模，实验室实验和现场测量，以提高我们的理解床力的全部分布。研究结果将用于检验关于底力分布对宏观流动特性和颗粒尺度相互作用的敏感性的假设。研究结果将被集成到广泛使用的连续流模型，从而帮助制定更准确的颗粒流灾害和景观演变模型。该奖项由地貌学和土地利用动力学（GLD）以及极端事件预测和恢复力（PREEVENTS）项目共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Landslides, rock falls, volcanic eruptions, rapid flows of mud, rock, and debris, snow avalanches, and sediment-laden floods are all deadly and costly natural hazards. They all also exemplify what are called natural granular flows. These events are hazardous in part due to their rapid and powerful nature, but also because models used to predict and mitigate their impacts remain imperfect. Seemingly simple questions still pose major challenges to scientists and engineers such as: How large will these events be? How far will they travel? What infrastructure is at risk? This project will investigate how granular flows interact with the things they flow over, with a particular focus on impact forces. The results will aid formulation of more accurate models of granular flow mobility and hazards. Outreach activities will be developed to highlight the excitement and utility of controlled laboratory experiments to study natural hazards. The investigators will develop these in collaboration with pedagogy experts, implement them in 4th-8th grade classrooms, and incorporate them into annual workshops for teachers and as interactive exploration stations at two science museums. The overarching goal of this project is to improve our understanding of the forces imparted by granular flows on their beds. This work is motivated by the hypothesis that many geomorphic processes and associated hazards are driven by the largest bed forces, rather than the mean force. The study will build on advances in granular mechanics and apply a novel blend of discrete element modeling, laboratory experiments, and field measurements to improve our understanding of the full distribution of bed forces. The results will be used to test hypotheses about the sensitivity of bed force distributions to macroscopic flow properties and grain-scale interactions. The findings will be integrated into widely used continuum flow models, and thereby aid the formulation of more accurate models of granular flow hazards and landscape evolution. This award is cofunded by the Geomorphology and Land-use Dynamics (GLD) and Prediction of and Resilience against Extreme Events (PREEVENTS) programs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.