Shock-induced reactive turbulent mixing at a density interface

平面激波撞击化学反应性球形密度不连续面（充满不同于周围气体的气泡）所引起的混合过程将进行实验和数值研究。特别地，充满在惰性气体中稀释的氢-氧混合物的气泡将在中性环境（例如氮气）中释放，并通过平面激波加速。初步计算表明，通过适当选择气泡内的惰性气体，通过气泡传播的激波将使局部温度升高到足以点燃H2-O2混合物燃烧的值，从而提供了化学反应开始时非常精确的流动几何和热物理条件知识。化学反应的进展将通过平面激光诱导荧光非侵入性测量局部羟基自由基OH的浓度来监测。在实验的同时，流动的数值模拟将使用由美国能源部高级科学计算计划下的芝加哥大学FLASH中心与Fausto Cattaneo教授及其团队密切合作开发的开源FLASH代码进行。分子混合将以与更常见的研究（射流、剪切层、内燃机）非常不同的几何形式进行研究。实验初始条件和点火时间将被精确表征。对化学反应的时间演化过程进行观察和模拟。最重要的是，对激波衍射和波混响引起的混合的理解将扩展到包括化学反应的影响。从更广泛的意义上讲，这些结果的相关性一直延伸到天体物理学领域，在这些领域中，冲击波点燃的燃烧和爆燃到爆轰的过渡被认为是某类超新星爆炸的主要驱动因素。该项目还通过定期让本科生和高中生参与我们的研究，对推广和教育产生了重大影响。来自州立大学外的少数族裔本科生通过威斯康星大学麦迪逊分校工程学院多样性事务办公室开发的一个项目被接待了10周，而高中生则通过麦迪逊高中组织的一个项目被接待了8周的暑期。

CBET - 0827285 BonazzaThe mixing processes induced by a planar shock wave striking a chemically reactive spherical density discontinuity (a bubble filled with a gas different than the surrounding) will be studied experimentally and numerically. In particular, a bubble filled with a hydrogen-oxygen mixture diluted in an inert gas will be released in a neutral environment (e.g. nitrogen) and accelerated by a planar shock. Preliminary calculations have demonstrated that, by appropriate choice of the inert gas inside the bubble, the shock propagating through the bubble will raise the local temperature to values large enough to ignite the combustion of the H2-O2 mixture thus providing very accurate knowledge of the flow geometry and thermophysical conditions at the start of the chemical reaction. The progress of the chemical reaction will be monitored by non-intrusively measuring the local concentration of the hydroxyl radical, OH, by planar laser induced fluorescence. In parallel to the experiments, numerical simulations of the flow will be performed using the open source FLASH code developed at the University of Chicago FLASH center under DOE's Advanced Scientific Computing Initiative working in close collaboration with Prof. Fausto Cattaneo and his team. Molecular mixing will be studied in a geometry very different from the more commonly investigated ones (jets, shear layers, internal combustion engines). The experimental initial condition and time of ignition will be precisely characterized. The time evolution of the chemical reaction will be observed and simulated. Most importantly, understanding of the mixing due to shock diffraction and wave reverberation will be extended to include the effects of the chemical reaction. In a broader sense, the relevance of these results reaches all the way into the field of astrophysics where shock-ignited combustion and deflagration to detonation transition are postulated to be the primary drivers in a certain class of supernova explosions. The program has also a significant impact on outreach and education by regularly involving undergraduate and high school students in our research. Minority undergraduate students from out of state universities have been hosted for 10 weeks through a program developed by the UW-Madison College of Engineering Diversity Affairs Office while high school students have been hosted for 8-week summer periods through a program organized by Madison's high schools.