Collaborative Research: Laboratory and theoretical study of geyser dynamics

黄石公园的老忠实间歇泉每年有超过400万游客，公众对间歇泉的迷恋是不可否认的。然而，对间歇泉的科学理解是不完整的。一个多世纪以来，人们一直认为间歇泉喷发是由地下管道中的水突然沸腾引起的，但科学家们并不清楚是什么触发了这些沸腾事件，以及地下管道的大小和形状如何影响间歇泉的行为。最近对黄石国家公园间歇泉、智利高原上的El Tatio和堪察加的间歇泉山谷的研究表明，这些地点的地下管道系统包括一个水库，该水库相对于主喷发管道的一侧偏移。在这样的系统中，蒸汽被捕获在侧边的储水池中，因此它被称为“气泡捕集器”。这种几何学的发现是几十年来最重大的进步，但研究人员才刚刚开始了解它如何影响间歇泉的行为。该团队将在实验室创建一个小型间歇泉装置，其中将包括一个气泡捕集器。他们将进行一系列实验，研究流体在这类系统中的行为。这项拟议的工作将使用数学模型将实验室中观察到的行为与我们在自然界中遇到的更大的系统联系起来。该项目将为本科生提供研究经验，并将通过既定的教师培训计划向教育工作者提供教学材料。实验室的间歇泉将在拉蒙特·多尔蒂地球天文台的开放参观中展出，每年有数千人参观。间歇泉代表着一种独特的热液系统，在这种系统中，两相(蒸汽和液体)流动的热力学和有利的管道几何形状结合在一起，产生了周期性的喷发。黄石公园的老忠实间歇泉每年有超过400万游客，公众对间歇泉的迷恋是不可否认的，但我们对间歇泉的科学理解是不完整的。然而，最近，来自黄石国家公园、智利高原上的El Tatio和堪察加的间歇泉山谷的间歇泉田的数据为管道几何形状提供了令人信服的证据，其中包括一个从喷发管道横向偏移的水库。这种所谓的“气泡陷阱”几何形状使得压缩蒸汽可以在不透水的屋顶下积聚，随着这个团队试图了解它对间歇泉动态行为的影响，它的发现重振了间歇泉的研究。到目前为止，实验室开发的间歇泉实验都没有准确地模拟在自然系统中观察到的所有行为，气泡捕集器管道几何形状的影响也没有得到彻底的探索。同样，数学模型已经为间歇泉研究提供了一个多世纪的信息，但现有的模型中没有一个考虑到与气泡捕集器管道几何形状相关的全部热力学和流体力学过程。该项目将通过结合新颖的实验室实验来解决这两个缺点，这些实验包括间歇泉遗失的部件和气泡捕集器。实验室模拟间歇泉将提供天然间歇泉的热力学过程和地下几何形状的理想化表示，使旨在阐明间歇泉系统的流体力学和热力学行为的一系列实验成为可能。同时，将开发数学模型来描述系统行为，这些关系将被用来提高我们对自然系统的理解。实验室间歇泉将能够对喷发触发的相互竞争的假说进行评估，全面的监测仪器将能够以前所未有的详细程度观察间歇泉过程。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With over 4 million annual visitors to Yellowstone's Old Faithful geyser, public fascination with geysers is undeniable. Yet, the scientific understanding of geysers is incomplete. While it has been understood for over a century that geyser eruptions are caused by the sudden boiling of water in underground conduits, scientists do not understand what triggers these boiling events, and how the size and shape of the underground conduits affect a geyser’s behavior. Recent studies at geyser fields in Yellowstone National Park, El Tatio on the Chilean altiplano, and the Geyser Valley in Kamchatka, have shown that the underground plumbing systems at these sites include a reservoir that is offset to the side relative to the main eruption conduit. In such systems, steam gets captured in the side reservoir, earning it the name ‘bubble trap’. The discovery of this geometry is the most significant advance in several decades, but researchers are only beginning to understand how it affects a geyser's behavior. This team will create a small geyser setup in the laboratory that will include a bubble trap. They will run a series of experiments to study how fluids behave in this type of system. The proposed work will use mathematical models to relate behaviors observed in the lab to the much larger systems that we encounter in nature. The project will provide research experiences for undergraduate students and will contribute instructional materials to educators through an established teacher training program. The laboratory geyser will be exhibited at the Lamont Doherty Earth Observatory open house, visited by thousands of people each year.Geysers represent a unique class of hydrothermal systems where the thermodynamics of two-phase (vapor and liquid) flow and favorable conduit geometries combine to produce episodic eruptions. With over 4 million annual visitors to Yellowstone's Old Faithful geyser, public fascination with geysers is undeniable, but our scientific understanding of geysers is incomplete. Recently, however, data from geyser fields in Yellowstone National Park, El Tatio on the Chilean altiplano, and the Geyser Valley in Kamchatka, have provided compelling evidence for conduit geometries that include a reservoir that is laterally offset from the eruption conduit. This so-called 'bubble trap' geometry allows compressed steam to accumulate under an impermeable roof, and its discovery has revitalized geyser research as this team seeks to understand its implications for a geyser's dynamic behavior. None of the laboratory geyser experiments developed to-date accurately simulates the full range of behaviors observed in natural systems, and the effects of bubble trap conduit geometries have not been explored thoroughly. Similarly, mathematical models have informed geyser research for more than a century, but none of the extant models considered the full range of thermodynamic and fluid mechanics processes associated with a bubble trap conduit geometry. This project will address both of these shortcomings by combining novel laboratory experiments that include the missing pieces for geysers with a bubble trap. The laboratory analog geyser will provide an idealized representation of the thermodynamic processes and subsurface geometries of natural geysers, enabling a series of experiments aimed at elucidating the fluid mechanical and thermodynamic behaviors of the geyser system. In parallel, mathematical models will be developed to describe the system behavior, and these relationships will be used to improve our understanding of natural systems. The laboratory geyser will enable the evaluation of competing hypotheses for eruption triggering, and comprehensive monitoring instrumentation will enable the observation of geyser processes in unprecedented detail.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.