Collaborative Research: Targeting Turbulence Using Smart Particles

合作研究：使用智能粒子瞄准湍流

• 批准号: 1905288
• 负责人: David Goldstein
• 金额: $ 25.79万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905288&HistoricalAwards=false
• 关键词: Collaborative; Research; Targeting; Turbulence; Using

Approximately 29 percent of all energy consumed in the U.S. is used to transport goods and people. Most of this energy is used to overcome drag forces produced by the turbulent flow of gases and liquids; only a modest reduction in drag would result in large fuel savings. Drag is associated with turbulent flow creating regions of concentrated vorticity near walls. Previous methods for reducing the drag forces, such as introducing substances (such as polymers) into the flow, did not exploit the known structure of the turbulence in a targeted way. When polymers are injected or bled into the near-wall turbulent boundary layer, they become distributed randomly, making it impractical in most cases to use these additives to reduce drag. This work seeks to answer: Can micro-particles containing a suitable additive and having specific physical properties be introduced into turbulent flow to achieve much greater drag reduction than traditional methods? The success of the present approach in reducing drag is expected to motivate the emergence of technologies focused on the development of micro-particles that can detect the nature of their own flow environment and respond by modifying that environment. For example, particles which segregate themselves into turbulent structures based on their density and subsequently dissolve will be examined first, but future smart particles might sense local flow properties, such as flow stain rates, and subsequently direct themselves to regions of the flow where their effects may be most impactful. It is easy to imagine how reducing drag on ships, cars, trains, and airplanes would have a broad impact on society.The proposed work aims to specifically target these structures by allowing particles, smaller than the smallest turbulent length scale and of the appropriate shape or density, to carry and release drag reducing agents as they collect in a natural way within or around such structures. Ideally, as one such structure is disrupted, remaining particles will migrate to the next in a disruptive cascade. Particle properties (especially particle sizes, densities, polymer properties, polymer release mechanisms, particle injection locations, and injection rates) and smart injection techniques that are most effective in reducing drag will be determined. It is proposed to study this concept using direct numerical simulation of the Navier-Stokes equations (which describe fluid motion) for the transitional case of turbulent spot evolution and for the fully turbulent flat plate boundary layer and channel flow cases. These situations cover the canonical transitional and turbulence internal and external flow regimes relevant to flow about ships as well as within pipelines.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.

在美国消耗的所有能源中，约有29％用于运输商品和人。大部分能量用于克服气体和液体湍流产生的阻力。只有适度的阻力减少才能节省大量燃料。 阻力与湍流相关，形成墙壁附近浓缩涡度的区域。 先前减少阻力力的方法，例如将物质（例如聚合物）引入流中，并未以靶向方式利用湍流的已知结构。当聚合物被注入或浸入近壁湍流边界层中时，它们会随机分布，在大多数情况下，使用这些添加剂来减少阻力是不切实际的。 这项工作试图回答：是否可以将包含合适的添加剂并具有特定物理特性的微颗粒引入湍流中，以比传统方法更大的阻力减少？预计目前的方法在减少阻力方面的成功将激发着专注于可以检测其自身流动环境本质并通过修改该环境做出响应的微粒发展的技术的出现。例如，将首先检查基于其密度并随后溶解的粒子将自己隔离为湍流结构，但是将来的智能粒子可能会感觉到局部流量特性，例如流量染色速率，然后将自己引导到其效果可能最有影响力的流动区域。可以很容易地想象，在船，汽车，火车和飞机上的阻力减少如何对社会产生广泛的影响。拟议的工作旨在通过允许颗粒允许颗粒（比最小的湍流长度或合适的形状或密度，可以在这种结构内或在此类结构周围收集自然的方式）来专门针对这些结构。理想情况下，由于一种这样的结构被破坏，剩余的颗粒将以破坏性的级联反应迁移到下一个。将确定粒子特性（尤其是粒度，密度，聚合物性能，聚合物释放机制，颗粒注入位置和注入速率）和最有效减少阻力的智能注入技术。提议使用Navier-Stokes方程的直接数值模拟（描述流体运动）来研究此概念，以用于湍流点演变的过渡情况以及完全湍流的平板边界层和通道流动案例。这些情况涵盖了与船只以及管道中有关的内部和外部流动制度的规范过渡和湍流。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛影响的审查标准通过评估来通过评估来支持的。