Petascale Simulation of Turbulent Stellar Hydrodynamics

该奖项促进了使用IBM开发的名为Blue Waters的大型新计算资源的科学研究，该资源计划于2011年在伊利诺伊大学部署。它提供旅费以支持主要研究人员、Blue Waters项目团队和供应商技术团队之间的技术协调。该项目包括准备数值代码，以便在Blue Waters上运行，以研究早期巨星生命末期氦闪事件的过程。这种持续时间相对较短（例如两年）的加速核燃烧事件可以从恒星内部吸收富含重元素的物质，并在恒星的外层被排出时将它们与外层混合，形成行星状星云。该计划首先以高分辨率对这一剧烈燃烧阶段进行短时间的三维全局模拟，以捕捉未燃烧的氢进入氦对流区的湍流。对这些高分辨率计算输出的统计分析将提供湍流、多流体卷带、混合和核燃烧的亚网格尺度参数化，然后可以将其纳入更大分辨率的模型中。具有较小尺度的携射和湍流燃烧参数化的粗分辨率模型将在更长的时间内进行整合，以确定氦闪的演变。该项目还包括使用一种新技术来组织蓝水处理器的计算工作，以更有效地利用它们的计算能力。如果成功，“蓝水”计划将提供对宇宙中重元素起源和扩散的深入了解。它还可以提供一种计算技术，使许多需要有效利用新兴的超大型、并行、多核计算系统的研究领域受益。

This award facilitates scientific research using the large new computational resource named Blue Waters being developed by IBM and scheduled to be deployed at the University of Illinois in 2011. It provides travel funds to support technical coordination between the principal investigators, the Blue Waters project team and vendor technical team.The project involves preparing numerical codes to be run on Blue Waters in a study of the course of helium flash events in early generation giant stars near the end of their lives. This relatively short duration (e.g. two years) event of accelerated nuclear burning can dredge up material enriched with heavier elements from the interior of the star and mix them with the outer envelope of the star as the latter is expelled, forming a planetary nebula. The plan is to first execute 3D, global simulations of this violent burning phase for short periods at high resolution to capture the turbulent entrainment of unburned hydrogen into the helium convection zone. Statistical analysis of the output from these high-resolution calculations will provide subgrid-scale parameterizations of turbulent, multifluid entrainment, mixing and nuclear burning that can then be incorporated in coarser resolution models. The coarser resolution models with parameterizations of the smaller scales of entrainment and turbulent combustion will then be integrated over much longer periods to determine the evolution of the helium flash. The project also involves using a novel technique to organize the computational work on the Blue Waters processors to use their computational power more effectively. If successful, the proposed work on Blue Waters will provide insights into the origin and dispersal of heavy elements in the universe. It could also provide a computational technique that would benefit a number of areas of research that need to make efficient use of the emerging class of very large, parallel, multi-core computing systems.