CAREER:The Role of Proximal Dynamics and Particle Aggregation in Ash Dispersal: An Educational, Numerical, Field and Laboratory Approach

职业：近端动力学和颗粒聚集在灰烬扩散中的作用：一种教育、数值、现场和实验室方法

• 批准号: 1150794
• 负责人: Josef Dufek
• 金额: $ 47.03万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1150794&HistoricalAwards=false
• 关键词: CAREER; Role; Proximal; Dynamics; Particle

Explosive volcanic eruptions can inject voluminous amounts of ash into the atmosphere potentially crippling global infrastructure as witnessed by the recent eruption of Eyjafjallajökull in Iceland. While significant improvements have been made in the development of ash dispersal models and in the conceptual understanding of processes that govern the transport of ash far from the volcanic vent, much of the uncertainty in current forecasts of ash dispersal occurs due to limited description of particle dynamics in the conduit and near the vent. The proposed work will examine the physical processes that modify the grain size distribution of particles across a spectrum of energies due to eruptive processes in the conduit and multiphase interaction in the plume using computational, field and laboratory approaches.Ash dispersal models have focused on long-range dispersal, incorporating conditions from atmospheric models. Due to the investment and advances in these fields, one of the goals of this work is to provide improved source terms and physical understanding that can be readily adopted into any dispersal model. To develop an integrated framework, we will address the following questions, objectives and related hypotheses: 1. How do post-fragmentation conduit processes play a role in setting the exit conditions into the atmosphere? 2. How do vent conditions and entrainment physics contribute to grain size sorting in plumes? 3. What role does hydrous aggregation play in the proximal distribution of ash? All of these questions will be closely linked and will make use of carefully chosen field examples, laboratory experiments, numerical simulations and visualization tools. This work will also develop an integrated set of fluid dynamics modules, teaching at a distance tools, and web based tools to enable high school students to learn more about volcanology and earth sciences in general. This approach has been designed to reach a broad high school audience, and in its first phase will reach several schools with large minority populations. Additionally these tools will be promoted to the broader public through web applications and through interactive three-dimensional visualizations tools that can be used in museum displays.

爆炸性火山爆发会将大量火山灰喷入大气层，有可能使全球基础设施瘫痪，最近冰岛埃亚菲亚德拉冰盖的爆发就是明证。虽然在制定火山灰扩散模型和从概念上理解火山灰远离火山口的迁移过程方面取得了重大进展，但由于对管道和火山口附近的颗粒动力学描述有限，目前对火山灰扩散的预测存在很大的不确定性。拟议的工作将审查物理过程，修改粒度分布的粒子在整个频谱的能量，由于喷发过程中的管道和多相相互作用的羽流使用计算，现场和实验室的方法，灰扩散模型侧重于远距离扩散，纳入大气模型的条件。由于在这些领域的投资和进步，这项工作的目标之一是提供改进的源项和物理的理解，可以很容易地采用到任何扩散模型。为了建立一个完整的框架，我们将解决以下问题，目标和相关假设：1。碎裂后的管道过程如何在设定进入大气层的出口条件方面发挥作用？2.喷口条件和卷吸物理学如何有助于羽流中颗粒大小的分选？3.水化聚集在灰的近端分布中起什么作用？所有这些问题都将密切联系在一起，并将利用精心挑选的现场实例、实验室实验、数值模拟和可视化工具。这项工作还将开发一套综合的流体动力学模块，远程教学工具和基于网络的工具，使高中学生能够更多地了解火山学和地球科学。这一方法旨在覆盖广大的高中受众，在第一阶段将覆盖少数民族人口众多的几所学校。此外，这些工具将通过网络应用程序和可用于博物馆展示的交互式三维可视化工具向更广泛的公众推广。