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Shock wave focusing to achieve high energy concentration

冲击波聚焦实现能量高度集中

基本信息

批准号：
1803592
负责人：
John McCartney
金额：
$ 30.81万
依托单位：
University of California-San Diego
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2022-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1803592&HistoricalAwards=false
关键词：
Shock wave focusing achieve energy

项目摘要

A shock wave is a thin discontinuous region over which fluid properties abruptly change from one state to another. Shock wave focusing occurs frequently both in nature and in a variety of man-made applications. It takes place when a shock wave propagates through a non-uniform or moving media and reflects from curved surfaces or through reflections with other shock waves. Extreme conditions created at the focal region - resulting in very high pressures and temperatures - can be either beneficial as in the case of shock wave lithotripsy to remove kidney stones or in inertial confinement fusion for energy generation, or detrimental as in the case of superbooms (a type of sonic boom). As the shock wave emerges from the focal region, after the shock focusing event, the shape of the shock is often fundamentally altered. Therefore, a deeper understanding of the shock focusing process, and how to control it, is critical to fully understand its consequences and how to best enhance or mitigate it as needed depending on the application at hand. Today, three-dimensional effects of shock wave focusing are not yet fully understood. Therefore, the principal goal of this research project is to develop a deeper understanding of the key factors that govern shock wave focusing in three dimensions using an experimental approach. This project will also provide opportunities to learn about shock wave dynamics for undergraduate students and high school students, particularly from underrepresented minorities.The primary goal of this research is to experimentally study shock wave focusing using an exploding wire setup capable of producing multiple simultaneous shock waves in two or three dimensions. Ultra high-speed photography coupled with visualization techniques will be used to determine the conditions when regular shock wave reflection transitions into irregular shock wave reflection. Another goal is to quantify the amount of energy focusing at the focal region given the competition between the weakening of each individual shock wave as it propagates radially outward from the exploding wire and the strengthening due to Mach shock generation.The proposed research is expected to lead to a much enhanced understanding of the principles of shock wave dynamics, and shock wave focusing, especially for three dimensional shocks with decaying fluid properties behind them ? in addition to providing a wealth of data to help verify numerical frameworks dealing with shock focusing scenarios.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

激波是一个很薄的不连续区域，在这个区域上流体性质会突然从一种状态转变为另一种状态。冲击波聚焦在自然界和各种人造应用中都经常发生。当冲击波通过非均匀或运动介质传播并从曲面反射或通过与其他冲击波的反射时，就会发生这种现象。在焦点区域产生的极端条件——导致非常高的压力和温度——可能是有益的，比如冲击波碎石术，以去除肾结石或惯性约束聚变发电，或者是有害的，比如超级爆（一种音爆）。当激波从震源区域出现时，在激波聚焦事件发生后，激波的形状往往会发生根本性的改变。因此，更深入地了解冲击聚焦过程，以及如何控制它，对于充分了解其后果以及如何根据需要根据手头的应用最好地增强或减轻它至关重要。今天，冲击波聚焦的三维效应还没有被完全理解。因此，本研究项目的主要目标是利用实验方法对影响冲击波三维聚焦的关键因素进行更深入的了解。该项目还将为本科生和高中生，特别是来自代表性不足的少数民族的学生提供学习冲击波动力学的机会。本研究的主要目标是通过实验研究冲击波聚焦的爆炸线装置，该装置能够在二维或三维空间同时产生多个冲击波。超高速摄影结合可视化技术将用于确定规则激波反射转变为不规则激波反射的条件。另一个目标是量化聚焦在焦点区域的能量，考虑到每个冲击波在爆炸导线径向向外传播时的减弱和马赫激波产生时的增强之间的竞争。所提出的研究预计将导致对激波动力学原理和激波聚焦原理的进一步理解，特别是对具有衰变流体性质的三维激波。除了提供丰富的数据，以帮助验证处理冲击聚焦场景的数值框架。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。