Collaborative research: Shock interaction with a complex hydrodynamic medium

PI：Vorobief，Peter/Jacobs，GustaafProposal编号：1603915/1603326当气体高速运动时，通常会形成压力冲击。对于小颗粒也存在的情况，提出了一项涉及实验和计算的综合研究。拟议工作的实际应用涉及到大量涉及混合的工程技术，如超音速和高超声速燃烧，以及粉尘爆炸(在煤矿和谷物或糖筒仓)。例如，在燃烧应用中，气-固/液流动的不完全混合直接导致性能损失和环境污染增加。建议研究颗粒流中激波驱动的不稳定性，其中气相中同时存在大尺度的密度梯度，而颗粒相的存在可能占体积平均密度的很大一部分。建议的工作旨在克服目前对激波驱动介质的纯流体动力学特性(Richtmyer-Meshkov不稳定性、二次不稳定性和向湍流的转变)和相同流动的多相特性之间的研究脱节。通过结合计算分析、实验以及理论和模型的发展，将建立一个基准集，以准备对相关物理的详细研究，不仅在总体流动行为方面，而且集中在斜压和颗粒-气体相互作用机制引起的更微妙的混合现象上。实验将在新墨西哥大学的激波管中进行，这是世界上最先进的此类研究设施之一。它的设计马赫数为4，高度模块化的结构允许研究与各种物体的冲击波相互作用，只需最小限度的重新配置。计算将使用欧拉-拉格朗日和欧拉-欧拉码，基于SDSU的PI开发的高阶加权本质非振荡(WENO)格式。这些程序将对激波和粒子云的相互作用进行验证。将确定播种和粒度分布中的不均匀对流动形态的影响。整个系统的三维计算和实验将提供对完全非线性流动发展的洞察。更好地理解激波驱动混合的基本物理原理将改进能源领域的设计，减少对自然资源的使用和对环境的影响。这项工作将吸引来自代表性不足群体的学生，鼓励他们在STEM相关领域追求长期职业生涯。

PI: Vorobieff, Peter / Jacobs, GustaafProposal Number: 1603915 / 1603326When a gas moves at high speeds, a pressure shock is often formed. A comprehensive study that involves experiments and computations is proposed for the case when small particles are also present. Practical applications of the proposed work are found in a plethora of engineering technologies that involve mixing, such as supersonic and hypersonic combustion, and dust explosions (in coal mines and in grain or sugar silos). For example, in combustion applications, incomplete mixing of gas-solid/liquid flows is directly responsible for performance losses and increased environmental pollution.It is proposed to study shock-driven instabilities in particle-laden flows, where large-scale density gradients are present in the gas phase simultaneously with presence of the particle phase, and the latter may account for a significant fraction of the volume-averaged density. The proposed effort aims to overcome the current disconnect between the studies of the purely hydrodynamic features of shock-driven media (Richtmyer-Meshkov instabilities (RMI), secondary instabilities, and transition to turbulence) and multiphase features of the same flows. By combining computational analysis, experiment and theoretical and model developments, a benchmark set will be developed to prepare for a detailed investigation of the relevant physics, not just in terms of gross flow behavior, but with focus on subtler mixing phenomena induced by baroclinic and particle-gas interaction mechanisms. Experiments will be conducted in the University of New Mexico shock tube, one of the most advanced research facilities of this type in the world. It has a design Mach number of 4 and a highly modular architecture allowing to study shock interaction with a wide variety of objects with minimal reconfiguration. Computations will be conducted with Eulerian-Lagrangian and Eulerian-Eulerian codes based on higher-order Weighted-Essentially-Non-Oscillatory (WENO) schemes that have been developed by the PI at SDSU. The codes will be validated for the interaction of shock and cloud of particles. Effects on flow morphology caused by non-uniformities in the seeding and particle size distribution will be determined. Three-dimensional computations of the complete system and experiment will provide insight into the fully non-linear flow development. A better understanding of the basic physics of shock-driven mixing will lead to improved designs in the energy area, reducing use of natural resources and impact on the environment. The work will engage students from underrepresented groups, encouraging them to pursue long-term careers in STEM-related fields.