Turbulent mixing between a shock-accelerated vortex ring and its surroundings

冲击加速涡环与其周围环境之间的湍流混合

• 批准号: 1939809
• 负责人: Riccardo Bonazza
• 金额: $ 31.99万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-15 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1939809&HistoricalAwards=false
• 关键词: Turbulent; mixing; between; shock; accelerated

When a shock wave propagates through a region occupied by different gases, it generates gas motions at the wave boundary that lead to mixing at much higher rates than would have occurred in the absence of the shock wave. Phenomena of this kind can occur in a category of jet engines designed to operate at extremely high speeds that are much higher than those used in conventional jet transport. The study of these kinds of flows is generally very challenging because flow properties such as velocity, local gas composition, and temperature vary in space and time in very complicated ways. This research project will study a simple version of this type of flow. The researchers will study the response of a vortex ring to impulsive acceleration. By the nature of the vortex ring flow field, this initial condition should contain a much more coherent, well organized, predictable and measurable vorticity field than that of the jet engine. The results will form a highly refined building block database which could be used to develop a predictive capability for the more complicated version of these flows. Graduate and undergraduate students will be heavily involved in the research, with members of underrepresented minorities recruited through different programs already existing on campus. This project also will provide education in and exposure to state-of-the-art technologies and some of the most current challenges in science and engineering. The turbulent mixing induced by the interaction of a planar shock wave with a vortex ring consisting of a gas different than its surroundings will be investigated using planar laser induced fluorescence (PLIF) and particle image velocimetry (PIV). The goal of the project is to measure some of the most relevant flow properties, including the concentrations of the two gas species and their velocities everywhere within the region where the gases mix. This objective will be pursued in two different ways: 1) measurements will be made at discrete instants in time, with very high spatial resolution, and 2) measurements will be carried out with lesser spatial resolution but using an imaging system that will allow to collect entire concentration fields at a rate of up to 20,000 fields per second.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.

当冲击波通过不同气体占据的区域传播时，它会在波边界处产生气体运动，从而导致混合的速率比没有冲击波的情况要高得多。这种现象可以发生在一类旨在以极高速度运行的喷气发动机中，这些速度比常规喷气运输中使用的速度高得多。对这类流量的研究通常非常具有挑战性，因为诸如速度，局部气体成分和温度等流动特性以非常复杂的方式变化。该研究项目将研究此类流量的简单版本。研究人员将研究涡流环对冲动加速度的响应。根据涡流环流场的性质，这种初始条件应包含比喷气发动机的连贯性，井井有条，可预测和可测量的涡度场。结果将形成一个高度精制的构建块数据库，该数据库可用于为这些流的更复杂版本开发预测能力。研究生和本科生将大量参与研究，而代表人数不足的少数民族成员通过校园中现有的不同计划招募。该项目还将提供有关最先进技术的教育和接触，以及科学和工程中最新的一些挑战。通过平面激光诱导的荧光（PLIF）（PLIF）和粒子图像速率（PIV）研究，将研究由平面冲击波与涡流环与周围环境不同的涡流环与涡流环相互作用引起的湍流混合。该项目的目的是测量一些最相关的流量特性，包括两种气体物种的浓度及其速度，到处都是气体混合的地区。该目标将以两种不同的方式进行：1）将在离散的瞬间进行测量，并以非常高的空间分辨率进行，并且2）将通过较少的空间分辨率进行测量，但要使用成像系统进行较少的分辨率，但使用成像系统，该系统将允许以每秒的速度来收集整个浓度领域，并通过秒数的授权来表达NSF的基础奖励。和更广泛的影响审查标准。