Computer simulations of giant fluctuations in mixing fluids

混合流体巨大波动的计算机模拟

• 批准号: 1115341
• 负责人: Aleksandar Donev
• 金额: $ 32.32万
• 依托单位: New York University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1115341&HistoricalAwards=false
• 关键词: Computer; simulations; giant; fluctuations; mixing

Thermal fluctuations in non-equilibrium systems exhibit remarkablebehavior compared to equilibrium systems. Giant fluctuations inbinary mixtures of miscible fluids have been observed, includingin recent experiments in microgravity. Novel mathematical andcomputational challenges need to be addressed in order to includethermal fluctuations in traditional computational fluid dynamics ina way that is consistent with statistical mechanics. This proposalis concerned with the design, mathematical analysis, and computerimplementation of finite-volume methods for fluctuating hydrodynamicsof fluid mixtures, as well as applications to diffusively mixingfluids in gravity. The following research directions are proposed:(1) Multi-resolution numerical schemes for solving the compressiblestochastic continuum equations; (2) Algorithms for incompressible,and (3) low Mach fluctuating hydrodynamics of miscible mixtures onstaggered and collocated grids; (4) Simulations of giant fluctuationsand comparisons to experiments; (5) Study of the contributionof advection by velocity fluctuations to transport in finitenon-equilibrium systems.Flows at micro and nano scales typical of new devices and biologicalsystems are affected by thermal fluctuations. These effects are oftenassumed small and are not included in traditional computationalfluid dynamics. However, giant fluctuations in the concentrationof a polymer solution have been observed in recent experimentsconducted in microgravity on a research space shuttle. Computersimulations are ideally suited for studying the details of thisphenomenon and comparing the predictions of existing theory tothe experimental findings. However, our community still lacksthe appropriate computational tools, including both algorithms andlarge-scale parallel codes, to attack this problem. The investigatorand his colleagues will develop such tools and use them to answerimportant scientific questions concerning fluctuations in fluids, inclose collaboration with experimentalists. The developed algorithmswill be implemented in a public domain code whose development is fundedthrough a Software Infrastructure for Sustained Innovation NSF grant.

与平衡系统相比，非平衡系统中的热涨落表现出可比较的行为。在最近的微重力实验中，已经观察到了可混溶流体的二元混合物中的巨大波动。新的数学和计算的挑战需要解决，以包括在传统的计算流体动力学的方式，是与统计力学一致的热波动。本文涉及流体混合物波动流体力学有限体积法的设计、数学分析和计算机实现，以及在重力作用下扩散混合流体中的应用。提出了以下几个研究方向：（1）可压缩随机连续方程的多分辨率数值方法;（2）不可压缩不可（5）研究了平流中速度脉动对有限区域输运的贡献--新设备和生物系统中典型的微米和纳米尺度的流动受到热波动的影响。这些影响通常被假设为很小，并且不包括在传统的计算流体动力学中。然而，最近在航天飞机上进行的微重力实验中观察到聚合物溶液浓度的巨大波动。计算机模拟非常适合研究这种现象的细节，并将现有理论的预测与实验结果进行比较。然而，我们的社区仍然缺乏适当的计算工具，包括算法和大规模并行代码，来解决这个问题。这位科学家和他的同事们将开发这样的工具，并利用它们来回答有关流体波动的重要科学问题，包括与实验学家的合作。开发的算法将在公共领域代码中实现，其开发由NSF资助的持续创新软件基础设施资助。