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

液滴在复杂流动中的破碎在各种环境和工业应用中是至关重要的，包括石油泄漏缓解策略以及制药和石化产品的制造。这些问题的特点是尺度范围很广，从设备和强制尺度到产生的最小液滴，使得它们的建模具有挑战性，并限制了工业过程的效率。在不同的应用和乳化过程中，液滴的粘度可能会有很大的不同，并且可能比职业流动大几个数量级。了解液滴粘度对破碎动力学的作用，从变形的时间尺度到所形成的液滴的大小，仍然是一个活跃的科学挑战。本次研究奖将利用新的计算技术来解决与破碎过程相关的复杂流动，推进我们的基础知识，并为开发用于环境和工程应用的实用模型提供信息。将对液滴破碎过程进行直接的数值模拟，从最小尺度的湍流和界面特征到更大尺度的初始变形。全双流体的N-S方程将被求解，利用新的自适应网格加密算法来求解大范围的尺度。将进行大量的模拟，扫描物理参数，以便提出一个一般的理论框架，描述湍流、粘度在解体发生中的作用、时间、几何形状和机制以及产生的液滴的大小和数量。然后，这些结果将被整合到环境和工业应用中使用的人口平衡模型中。本奖项将使人们更好地了解在动荡环境中破碎液滴的基本原理。通过这一奖项，普林斯顿大学工程和环境科学专业的本科生和研究生将面临这些关键的工业和环境挑战，这些挑战需要对基础多相流进行研究。开源方法的使用将通过教学和K-12推广活动来推广。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.