CAREER: Predictive Simulations of Dilute-Dense Multiphase Flows and Application to Mixed Avalanches

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。0846577 Haselbacher本提案的研究目标是使用创新的数值方法和最低限度的经验主义来使用预测模拟，以了解管理混合流/粉雪雪崩(MA)的物理过程。MA由密集的核心和由大雪颗粒组成的跳跃层组成，下面是由小雪颗粒组成的稀薄的湍流粉末云。这项建议的教育目标是开发一门关于科学和工程中预测模拟的创新课程，并开发一种基于模拟的计算机游戏，向初中生教授流体力学的概念。智力上的优点：拟议的预测模拟有可能改变我们对稀密多相流一般以及特别是混合雪崩的理解。模拟的变革性影响来自于自然发生或人工触发的MA的全面实验的危险性质和遇到的困难，以及与较小规模实验相关的局限性。从拟议的研究中获得的更好的理解将导致对高度破坏性的混合雪崩的大小、耗尽长度和危险地图的更准确的预测，从而保护人类的生命和基础设施。量纲分析被用来构建一个计算上容易处理的全尺度移动平均模型，该模型保留了重要物理过程的相对标度。预测模拟基于一种创造性和合理的方法，将现有的致密核、跃变层和粉末云模拟工具结合在一起，提供了创新的集成多相流模拟能力，也极大地提高了雪崩模拟的技术水平。将使用分尺度模拟来减少和量化模型尺度上的不确定性。考虑到他在计算多相流体力学和大规模高性能计算方面的背景，PI是唯一有资格执行模拟的人。与世界领先的雪崩研究机构之一瑞士联邦雪崩研究所的合作，确保了获得全面和模型规模雪崩的独特实验数据，以验证集成的模拟代码并评估其预测能力。PI可以获得地方和国家高性能计算中心的资源来进行拟议的模拟。广泛的影响：本提议中描述的综合研究和教育计划将产生以下广泛影响。首先，科学和工程中预测模拟的创新高级课程将培训新一代科学家和工程师将模拟用作虚拟实验。预测性模拟将使社会受益，因为它们允许自信地为无法使用理论或实验研究的系统做出关键决策。其次，这款基于模拟的电脑游戏将与佛罗里达州纽伯里橡树景中学的科学教师合作开发，该中学面向大部分经济困难的儿童。这款电脑游戏将在互联网上传播，有可能接触到非常大量的初中生和高中生，激发他们在科学和工程领域追求职业生涯的热情，向他们介绍预测模拟的力量，并帮助他们掌握在基于想法的未来经济中脱颖而出的技能。第三，本科生将协助预测模拟的研究和计算机游戏的开发，从而积累现代计算方法的宝贵经验。作为综合研究和教育计划的一部分而取得的成果将发表在相关文献中。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).0846577HaselbacherThe research objective of this proposal is to use predictive simulations using innovative numerical methods and minimal empiricism to understand the physical processes that govern mixed flow/powder snow avalanches (MA). MA consist of a dense core and saltation layer of large snow particles beneath a dilute turbulent powder cloud of small snow particles. The education objectives of this proposal are to develop an innovative course on predictive simulations in science and engineering and to develop a simulation-based computer game to teach fluid mechanics concepts to middle and high school kids.Intellectual Merit: The proposed predictive simulations have the potential to transform our understanding of dilute dense multiphase flows in general and mixed avalanches in particular. The transformative impact of the simulations derives from the dangerous nature of and difficulties encountered in full scale experiments with naturally occurring or artificially triggered MA and the limitations associated with experiments at smaller scales. The improved understanding gained from the proposed research will result in more accurate predictions of the size, run out lengths, and hazard maps of highly destructive mixed avalanches and hence protect human lives and infrastructure. Dimensional analysis is used to construct a computationally tractable model of a full scale MA that retains the relative scaling of the important physical processes. The predictive simulations are based on a creative and rational approach of coupling existing simulation tools for the dense core, saltation layer, and the powder cloud to give an innovative integrated multiphase flow simulation capability that also greatly advances the state of the art in avalanche simulations. Subscale simulations will be used to reduce and quantify uncertainty at the model scale. The PI is uniquely qualified to perform the simulations given his background in computational multiphase fluid dynamics and large scale high performance computations. The collaboration with one of the worlds leading institutes for research on avalanches, the Swiss Federal Institute for Avalanche Research, ensures access to unique experimental data on full scale and model scale avalanches to validate the integrated simulation code and assess its predictive capability. The PI has access to resources at local and national high performance computing centers to carry out the proposed simulations.Broader Impacts: The integrated research and education plan described in this proposal will have the following broad impacts. First, the innovative advanced course on predictive simulations in science and engineering will train a new generation of scientists and engineers in using simulations as virtual experiments. Predictive simulations will benefit society because they allow critical decisions to be made with confidence for systems that cannot be studied using theory or experiments. Second, the simulation based computer game will be developed in collaboration with science teachers from Oak View Middle School in Newberry, FL that caters to a large percentage of financially disadvantaged kids. The computer game will be disseminated over the Internet and has the potential to reach a very large number of middle and high-school students, excite them about pursuing a career in science and engineering, introduce them to the power of predictive simulations and help provide them with the skills to excel in tomorrows economy based on ideas. Third, an undergraduate student will assist in the research on predictive simulations and the development of the computer game and therefore gather valuable experience with modern computational methods. The results obtained as part of the integrated research and education plan will be published in the relevant literature.