Shock-induced turbulent multi-material mixing

美国国家工程院已经将“从核聚变中提供能量”确定为工程学的重大挑战之一。惯性约束核聚变（ICF）是一种可持续的清洁能源，在解决能源安全和全球气候变化问题方面可能发挥巨大作用。richhtmyer - meshkov （RM）流体动力不稳定性导致胶囊界面过早混合已被确定为限制ICF性能的关键因素。虽然ICF问题要复杂得多，但对激波混合流体动力学的预测模拟是更好地设计ICF目标的关键。所提出的研究需要在一个简单而现实的结构中高保真地模拟激波诱导的多材料混合。问题的快速时间尺度限制了实验测量的范围，因此，数值模拟通过允许探索实验无法达到的流动物理的重要方面，在弥合理论和实验之间的差距方面发挥着关键作用。与在模拟中重复条件的实验室实验密切配合，将允许在大尺度上对计算结果进行系统验证。在前所未有的空间分辨率下，RMI驱动的湍流数据库有望实现，这将允许研究强驱动瞬态流中湍流物理的基本问题，并支持开发用于变密度湍流的新型亚尺度闭包。

The National Academy of Engineering has identified "Provide Energy from Fusion" as one of the grand challenges for engineering. Inertially confined fusion (ICF) presents a source of clean energy that is sustainable and has a potentially huge role to play in addressing concerns over energy security and global climate change. The Richtmyer-Meshkov (RM) hydrodynamic instability that causes premature mixing of the capsule interface has been identified as a critical factor that limits the performance of ICF. Though the ICF problem is far more complex, predictive simulations of the hydrodynamics of shock-induced mixing is a key enabler for better design of ICF targets.The proposed research entails high fidelity simulations of shock-induced multi-material mixing in a simple yet realistic configuration. The fast time scales of the problem limit the scope of experimental measurements and hence, numerical simulations have a critical role to play in bridging the gap between theory and experiments by allowing exploration of important aspects of the flow physics that are inaccessible to experiments. Close coordination with a laboratory experiment whose conditions are duplicated in the simulations will allow systematic validation of the computed results at large-scales. Databases on RMI driven turbulence at unprecedented spatial resolution are expected and will allow fundamental questions about turbulence physics in strongly driven transient flows to be investigated and also support development of novel sub-scale closures for variable density turbulence.