Collaborative Research: Heterogeneous Bubble Dynamics in Volcanic Conduits

火山爆发会对生活、基础设施、商业和气候产生重大影响。喷发的岩浆是热岩石碎片（以前是岩浆）的混合物，如火山灰和火山气体，这些气体在喷发的岩浆中以气泡的形式被运送到地表。气泡可能同时限制岩浆气体，导致气体压力过大，或者在气泡聚并过程中形成渗透性网络，从而促进协同气体损失。因此，气泡在岩浆上升速率的反馈中起着至关重要的作用，并影响着喷发的方式和爆发强度。这个项目将进一步加深我们对火山爆发期间影响气泡和岩浆气体的各种过程的定量理解。我们将开发一个新的气泡尺度的数值模型，用于气泡的生长、变形和合并。该模型将根据专门设计的实验室实验进行校准，以促进经验数据的整合。然后，将气泡尺度模型与多相管道流模型相结合，以解决以下问题：(1)具有多分散气泡尺寸分布的喷发岩浆中气体压力的时空演化；(2)岩浆破碎的意义；(3)喷发岩浆剪切变形过程中的气泡聚并；(4)通过聚结气泡的渗透性流动造成的开系统气体损失；(5)上升岩浆内部剪切定位。

Volcanic eruptions can have significant impact on life, infrastructure, commerce and climate. Erupting magma is a mixture of hot rock fragments (formerly magma), such as volcanic ash, and volcanic gases that are transported to surface as bubbles within the erupting magma. Bubbles may both, confine magmatic gases potentially resulting in large excess gas pressures, or they may facilitate syneruptive gas loss by forming permeable networks during bubble coalescence. Consequently, bubbles play a crucial role in a feedback with magma ascent rate and affect the style and explosive intensity of eruptions.This project will further our quantitative understanding of the various processes that affect bubbles and magmatic gases during volcanic eruptions. We will develop a new bubble-scale numerical model for bubble growth, deformation and coalescence. The model will be calibrated to laboratory experiments that are specifically designed to facilitate the integration of empirical data. The bubble-scale model will then be coupled with a multiphase conduit flow model to address problems such as (1) the spatiotemporal evolution of gas pressure in an erupting magma with a polydisperse bubble size distribution; (2) the implications for magma fragmentation; (3) bubble coalescence during shear deformation of the erupting magma; (4) open-system gas loss by permeable flow through coalesced bubbles; and (5) shear localization within the ascending magma.