Direct numerical simulations of droplet break-up in turbulence in inertial and viscous regimes

复杂流体中的液滴破碎在各种环境和工业应用中至关重要，包括减少溢油策略，以及制药和石化产品的制造。这些问题的特点是范围广泛的尺度，从设备和强制尺度到最小的被创建的液滴，使他们的建模具有挑战性，并限制了工业过程的效率。液滴的粘度可以在不同的应用程序之间以及在乳化过程中发生显著变化，并且可以比职业流量大几个数量级。从变形的时间尺度到最终形成的液滴的大小，了解液滴粘度在破碎动力学中的作用仍然是一个积极的科学挑战。目前的研究奖项将利用新的计算技术来解决与破裂过程相关的复杂流动，提高我们的基础知识，并为环境和工程应用中使用的实际模型的开发提供信息。将进行液滴破碎过程的直接数值模拟，从最小尺度的湍流和界面特征到负责初始变形的更大尺度。完整的双流体Navier-Stokes方程将被解决，利用新的自适应网格细化算法来解决大范围的尺度。将进行大规模的模拟活动，扫描物理参数，以提出一个一般的理论框架，描述湍流，粘度在破裂发生，时间，几何形状和机制中的作用，以及产生的液滴的大小和数量。然后将这些结果纳入环境和工业应用中使用的人口平衡模型。本奖项将提高对湍流环境中液滴破裂的基本理解。通过该奖项，普林斯顿大学工程与环境科学专业的本科生和研究生将接触到这些关键的工业和环境挑战，这些挑战需要对基本多相流进行研究。将通过教学和K-12外展活动促进开源方法的使用。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。

Droplet break-up in complex flows is critical in various environmental and industrial applications, including oil spill mitigation strategies, and the manufacturing of pharmaceuticals and petrochemical products. These problems are characterized by a wide range of scales, from the device and forcing scales to the smallest drops being created, making their modeling challenging and limiting the efficiency of industrial processes. The viscosity of the droplet can vary significantly from one application to another as well as during emulsification processes and can be orders of magnitude larger than the career flow. Understanding the role of the droplet viscosity on the fragmentation dynamics, from the time scale of deformation to the size of the resulting drops being formed remains an active scientific challenge. The present research award will leverage novel computational techniques to resolve complex flows associated with break-up processes, advancing our fundamental knowledge, and informing the development of practical models used in environmental and engineering applications.Direct numerical simulations of the drop break-up processes will be performed, resolving from the smallest scale of the turbulent flow and interfacial feature to the larger scale responsible for initial deformation. The full two-fluids Navier-Stokes equations will be solved, leveraging novel adaptive mesh refinement algorithm to resolve the large range of scales. Large campaigns of simulations will be performed, scanning the physical parameters in order to propose a general theoretical framework describing the role of turbulence, viscosity in the break-up occurrence, time, geometry and mechanisms and the resulting size and number of droplets being produced. These results will then be integrated within population balance models used in environmental and industrial applications. The present award will lead to improved fundamental understanding in break-up of drops in turbulent environment. Through this award, undergraduate and graduate students at Princeton in Engineering and Environmental sciences will be exposed to these critical industrial and environmental challenges that requires research on fundamental multi-phase flows. The use of open-source methods will be promoted through teaching and K-12 outreach activities.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.