Experiments on Convection and Turbulence in Earth's Core

地核对流和湍流实验

• 批准号: 9902741
• 负责人: Peter Olson
• 金额: $ 14.82万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2001-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9902741&HistoricalAwards=false
• 关键词: Experiments; Convection; Turbulence; Earth; Core

The goal of this research project is to simulate the flow in the Earth's liquid outer core using laboratory fluid dynamic models. The results of this study will be used, together with geophysical observations and numerical models, to probe the workings of the geodynamo. Two phenomena important in the geodynamo will be investigated. The first concerns the origin of large scale motions in the outer core and their relationshop to the three-dimensional seismic structure of the lower mantle. The investigators will study experimentally the structure of convection in rotating fluid shells with nearly radial buoyancy forces, subject to patterns of boundary heterogeneity inferred from lower mantle seismic structure. The results will help constrain the nature of core-mantly interaction, specifically how convection in the outer core is affected by the laterally variable conditions at the core-mantle boundary, including variable heat flow, topogrpahy and stable layering. The results should provide a basis for identifying effects of mantle heterogeneity on the long-term behavior of the core and the geodynamo. The second project is to apply measurements from laboratory experiments of hydromagnetic turbulent flow to turbulence in the outer core. The investigators will perform an expermental study of tutbulence generated in a diffrentially rotatin cylinder of liquid gallium in the presence of uniform magnetic fields. Properties of this magnetic Taylor-Couette flow will be used to estiate the turbulent diffusivity over the range of experimentally accessible paramenter, for extrapolation to conditions in the Earth's core.

该研究项目的目的是使用实验室流体动态模型模拟地球液体外芯中的流动。 这项研究的结果将与地球物理观测和数值模型一起使用，以探测Geodynamo的工作。 将研究在Geodynamo中重要的两个现象。 第一个涉及外部核心中大规模动作的起源及其关系速度与下地幔的三维地震结构的起源。 研究人员将通过实验研究以几乎径向浮力的旋转流体壳中对流的结构，但要从下地幔地震地震结构推断出的边界异质性模式。 结果将有助于限制核心 - 明显相互作用的性质，特别是外芯中的对流如何受到核心隐地边界的横向可变条件的影响，包括可变的热流，托普普希和稳定的分层。 结果应为识别地幔异质性对核心和地球怪物长期行为的影响提供基础。 第二个项目是将水力磁湍流实验实验中的测量值应用于外部核心的湍流。 研究人员将对在存在均匀磁场的情况下在液态壳的衍射旋转蛋白圆柱体中产生的tutbulence进行实验研究。 这种磁性泰勒 - 库特流的性能将用于估计实验可访问的牧板范围内的湍流扩散率，以推断到地球核心中的条件上。