Collaborative Research: Measurement and Modeling of Air Entrainment and Ash Distribution in Weak Volcanic Plumes

合作研究：弱火山羽流中空气夹带和灰分分布的测量和建模

• 批准号: 1346577
• 负责人: Raul Cal
• 金额: $ 25.61万
• 依托单位: Portland State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1346577&HistoricalAwards=false
• 关键词: Collaborative; Research; Measurement; Modeling; Air

The 2010 eruption of Eyjafjallajökull volcano in Iceland resulted in weeks of air traffic disruption and more than a billion dollars of economic losses. The disruption was exacerbated by limitations in the accuracy of models used to forecast the size, location, and ash concentration of the cloud. The pre-2010 airline industry policy was to avoid any volcanic ash during flight, and existing models predicted that the plume covered much of Europe. This has provided a new challenge to forecasters, as the rate that ash is fed into the cloud cannot be accurately estimated in complex flow situations. This rate is usually determined from the height of the plume above the volcano, but it can vary significantly due to many factors, including eruptive conditions, atmospheric properties, and local wind speeds. Hence, there is a vital need to develop improved models for realistic conditions.Traditional plume models assume flow in a calm atmosphere, but plumes are significantly modified by perpendicular cross flows with varying scales of turbulence. While cross flow has been considered in some models, the accuracy is still quite crude. This study will develop an improved understanding of volcanic plumes in a stratified cross flow, which will be used to aid in forecasting the dispersal of hazardous ash clouds. Advanced experimental techniques will be used to measure the flow in a laboratory scale plume. These results will be incorporated directly into a state-of-the-art analytical model, which will more accurately quantify the ash density distribution for volcanic scales. In addition, this research will be presented to the broad public audience through small-scale, hands-on laboratory demonstrations at the Oregon Museum of Science and Industry (OMSI).

2010年在冰岛举行的Eyjafjallajökull火山爆发导致空中交通中断和超过十亿美元的经济损失。通过用于预测云的大小，位置和灰分浓度的模型的准确性的局限性，破坏了破坏。 2010年之前的航空业政策是避免在飞行过程中进行任何火山灰，现有模型预测羽流覆盖了欧洲大部分地区。这为森林人提供了一个新的挑战，因为在复杂的流动情况下，无法准确估算灰分喂入云的速率。该速率通常是根据火山上方的羽流的高度确定的，但是由于许多因素，包括喷发条件，大气特性和局部风速，它可能会有很大差异。因此，至关重要的是开发改进的现实状况模型。传统的羽流模型假设在平静的气氛中流动，但是羽毛通过垂直的交叉流动具有不同尺寸的湍流。尽管在某些模型中考虑了交叉流，但准确性仍然很粗糙。这项研究将在分层的横流中对火山羽流的了解，这将用于预测危险灰云的分散体。先进的实验技术将用于测量实验室规模羽流中的流量。这些结果将直接纳入最先进的分析模型，该模型将更准确地量化火山尺度的灰密度分布。此外，这项研究将通过俄勒冈州科学与工业博物馆（OMSI）的小规模，动手实验室示范向广泛的公众观众展示。