Towards manipulating three-dimensional bluff-body wakes.

致力于操纵三维钝体尾流。

• 批准号: RGPIN-2019-04382
• 负责人: Martinuzzi, Robert
• 金额: $ 4.01万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=737595
• 关键词: Towards; manipulating; three; dimensional; bluff

Shifting wind patterns and gusting in the lee of buildings, ground vehicles or exposed pipelines are examples of turbulent bluff-body wakes. The flow impinges on the front of the body and detaches, or separates, along the sides resulting in reverse flow regions. The recirculating region dynamics are characterized by fluctuating velocity and pressure. The fluctuation amplitude depends on the strength and interaction of moving vortices generated in the recirculating region. These dynamics induce deleterious unsteady forces on the body, increase drag and enhance dispersion downstream. In contrast, bluff-body appendages are used in chemical reactors or combustors to enhance mixing and benefit higher product yield or cleaner combustion. Hence, the ability to manipulate bluff-body wakes to suppress or amplify dynamics is of engineering interest. The proposed research program is a framework for understanding and manipulating wake flows. A fundamental understanding the physics underlying the wake dynamics is to be gained. To this end, the influence of the on-coming flow and body shape on the strength of vortices and their interactions will be characterized. From this baseline, changes to the wake dynamics due to local forcing, introduced through pulsating jets along the obstacle surface, will be investigated. How these manipulations affect the unsteady forces, drag and downstream mixing will be characterized. These investigations are enabled by new techniques developed to represent and model the vortex interactions, based on compact mathematical formulations, predict the response to local forcing and optimize the manipulation parameters for suppressing or amplifying wake fluctuations. Optimization will be based on machine learning principles. These techniques are drawn from mathematics, signal processing and artificial intelligence communities, highlighting the interdisciplinary nature of this research. The knowledge and models developed in the program are applicable to a broad class of turbulent separated flows and thus of fundamental interest to the research community. The developed modelling techniques are relevant to industrial applications. These yield new technologies for flow monitoring and early-detection, which are suited for process control and damage mitigation for inaccessible or remote environments, such as chemical reactors and exposed pipelines. The knowledge gained in wake manipulation is anticipated to be significant for: ground transportation, reducing fuel consumption and increasing high-speed stability; and for chemical reactors or combustors, where mixing controls efficiency, product quality and yield. Compact modelling and machine learning can contribute to the design of autonomous systems. Overall, this program thus offers a context for developing skills and training highly qualified personnel for emerging technologies.

在建筑物、地面车辆或暴露的管道的背风处，改变风的模式和阵风是湍流钝体尾流的例子。流动冲击在主体的前部上，并沿沿着侧分离或分离，从而导致反向流动区域。回流区动力学的特征是脉动速度和压力。脉动幅度取决于回流区中产生的运动涡的强度和相互作用。这些动力学在物体上引起有害的非定常力，增加阻力并增强下游的扩散。相比之下，钝体附件用于化学反应器或燃烧室中以增强混合并有利于更高的产物产率或更清洁的燃烧。因此，操纵钝体尾流以抑制或放大动力学的能力是工程上感兴趣的。 拟议的研究计划是一个框架，了解和操纵尾流。对尾流动力学的物理基础有一个基本的了解。为此，即将到来的流动和身体的形状上的涡流的强度和它们的相互作用的影响将被表征。从这一基线出发，将研究通过脉动射流沿着障碍物表面引入的局部强迫引起的尾流动力学变化。这些操作如何影响非定常力，阻力和下游混合的特点。这些调查是使开发的新技术来表示和模拟的涡的相互作用，紧凑的数学公式的基础上，预测响应当地强迫和优化的操纵参数，抑制或放大尾流波动。优化将基于机器学习原理。这些技术来自数学，信号处理和人工智能社区，突出了这项研究的跨学科性质。 该计划中开发的知识和模型适用于广泛的湍流分离流，因此对研究界具有根本意义。开发的建模技术与工业应用相关。这些产生了用于流量监测和早期检测的新技术，适用于难以接近或偏远环境的过程控制和损害缓解，例如化学反应器和暴露的管道。在尾流操纵方面获得的知识预计将对以下方面具有重要意义：地面运输、减少燃料消耗和提高高速稳定性;以及化学反应器或燃烧室，其中混合控制效率、产品质量和产量。紧凑的建模和机器学习有助于自主系统的设计。总的来说，该计划因此提供了一个背景下，发展技能和培训高素质的人才，为新兴技术。