Parameterization of Small Scale Flow Structures in Earth's Outer Core

地球外核小尺度流动结构的参数化

• 批准号: 0000400
• 负责人: David Loper
• 金额: $ 23.08万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0000400&HistoricalAwards=false
• 关键词: Parameterization; Small; Scale; Flow; Structures

EAR-0000400 Loper, David This is a proposal to model, analyze and parameterize small-scale flows relevant to Earth's core and the geodynamo problem. The research project will consist of three phases, roughly coinciding with the three year duration of the grant. The first phase consists of solving explicitly for the local velocity and magnetic fields generated in a rotating hydromagnetic fluid by a small-scale buoyant parcel of prescribed (Gaussian) shape, including effects of the viscous, Lorentz and inertia forces and ambient stratification. This portion of the project is the most straightforward, although determination of the rise velocity may require solution of a non-linear problem when inertia or stratification is included. In the second phase the solutions obtained during the first phase will be generalized to include the effect of parcel deformation by the fluid flow and the associated temporal evolution of the flow structures. Also, the short-term temporal development of the wake structure associated with a Gaussian parcel, starting from an initial static state, will be analyzed. It is anticipated that this phase will involve a combination of classical analysis and numerical computation. In the third phase the solutions found during the first two phases will be used to quantify (i.e., parameterize) four important nonlinear effects: helicity, electromotive force, Reynolds stress and effective diffusivity. The first two of these are important in the development of more realistic a-w and a2 dynamo models, while the last two should lead to an improvement in the parameterization of small-scale motions in fully 3-D numerical models.

Loper，大卫这是一个对与地核和地球发电机问题相关的小尺度流动进行建模、分析和参数化的建议。该研究项目将包括三个阶段，大致与赠款的三年期限相吻合。第一阶段包括明确解决的本地速度和磁场中产生的旋转磁流体由一个小规模的浮力包裹规定的（高斯）形状，包括粘性，洛伦兹和惯性力和环境分层的影响。项目的这一部分是最直接的，尽管当包括惯性或分层时，确定上升速度可能需要解决非线性问题。在第二阶段中，在第一阶段期间获得的解决方案将被概括为包括由流体流动和相关的流动结构的时间演变的包裹变形的效果。此外，从初始静态开始，将分析与高斯包裹相关的尾流结构的短期时间发展。预计这一阶段将涉及经典分析和数值计算的结合。在第三阶段中，在前两个阶段中找到的解决方案将用于量化（即，参数）四个重要的非线性效应：螺旋度、电动势、雷诺应力和有效扩散系数。其中前两个是重要的，在更现实的a-w和a2发电机模型的发展，而最后两个应导致在完全3-D数值模型的小尺度运动的参数化的改进。