UNS: Resolving the Dynamics of Particles in Turbulent Wall-Bounded Flow: DNS and Experiments

UNS：解析湍流壁界流中的粒子动力学：DNS 和实验

• 批准号: 1510154
• 负责人: Ellen Longmire
• 金额: $ 37.49万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1510154&HistoricalAwards=false
• 关键词: UNS; Resolving; Dynamics; Particles; Turbulent

CBET - 1510154PI: Longmire, EllenTurbulent flows containing discrete particles occur in many environmental and industrial processes related to climate prediction, energy production, and environmental conservation. In environmental flows, particles may be natural (plankton, spores, sediment, or dust) or pollutants (plastics, exhaust or fallout precipitates). These flows are difficult to understand and predict due to the wide range of turbulence scales in the fluid as well as the complex physical interactions that occur on the scale of the particle diameter. The goal of the proposed research is to advance experimental and numerical simulation capabilities to resolve particle/turbulence, particle/particle, and particle/wall interactions in turbulent flows near solid surfaces where these interactions often determine particle deposition and resuspension rates, mixing, and transport.Complementary experiments and direct numerical simulations will investigate particles released into liquid turbulent boundary layer flows in a controlled fashion. Single moving particles and pairs of colliding particles will be considered where the particle diameter exceeds the smallest turbulence scales and where the particle Reynolds number is significant. Experiments will employ three-dimensional tracking of discrete particles combined with time-resolved tomographic particle imaging velocimetry to quantify translation and rotation, slip velocities, and spatial velocity gradients experienced by individual and colliding particles. A novel conservative overset grid method for unstructured grids will be developed and applied to simulate and fully resolve flow and stresses on moving particles in turbulent flow matching the experimental conditions. The results will be applied to assess existing particle/force coupling models and to suggest model improvements. The project will involve graduate and undergraduate researchers. The project team will work with teachers and students at a local elementary school to spark interest in science and engineering and to develop hands on physics and engineering activities that can be incorporated into the required science curriculum.

CBET-1510154 PI：Longmire，EllenTurbuent流动包含离散颗粒，存在于与气候预测、能源生产和环境保护相关的许多环境和工业过程中。在环境流中，颗粒可能是天然的(浮游生物、孢子、沉积物或粉尘)，也可能是污染物(塑料、废气或尘埃沉淀物)。这些流动很难理解和预测，因为流体中的湍流尺度范围很广，以及在颗粒直径尺度上发生的复杂物理相互作用。这项研究的目的是提高实验和数值模拟能力，以解决固体表面附近湍流中颗粒/湍流、颗粒/颗粒和颗粒/壁面的相互作用，这些相互作用通常决定颗粒的沉积和再悬浮速率、混合和输运。补充实验和直接数值模拟将研究以受控方式释放到液体湍流边界层流动中的颗粒。在粒子直径超过最小湍流尺度且粒子雷诺数显著的情况下，将考虑单个运动粒子和成对碰撞粒子。实验将使用离散粒子的三维跟踪与时间分辨断层扫描粒子成像测速仪相结合，以量化单个粒子和碰撞粒子经历的平移和旋转、滑动速度和空间速度梯度。发展了一种新的非结构网格守恒覆盖网格方法，并将其应用于模拟和完全求解符合实验条件的湍流中的流动和运动颗粒的应力。结果将用于评估现有的粒子/力耦合模型，并提出改进模型的建议。该项目将涉及研究生和本科生研究人员。该项目团队将与当地一所小学的教师和学生合作，激发人们对科学和工程的兴趣，并开发可纳入必修科学课程的物理和工程活动。