Smart skin for control of wall-bounded turbulent flows

用于控制壁面湍流的智能蒙皮

• 批准号: RGPIN-2020-07231
• 负责人: Ghaemi, Sina
• 金额: $ 3.35万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718741
• 关键词: Smart; skin; control; wall; bounded

A boundary layer is a thin layer of fluid in the immediate vicinity of a solid surface where fluid velocity transitions from the velocity of the solid surface to the bulk fluid velocity. The shear stress in the fluid generates this velocity gradient, and projects as skin-friction' on the surface. In most industrial situations, for example, the flow over an aircraft or inside a pipeline, the motions of fluid elements in the boundary layer are chaotic. Such a fluid layer is known as a turbulent boundary layer (TBL), and has a larger velocity gradient that generates greater skin-friction. In addition, when an increasing pressure gradient is imposed on a TBL, like in a diffuser or on an aircraft wing, the TBL may separate from the surface. This generates pressure drag' and strong fluid-structure interactions. As a result, the TBL is the chief source of high fuel consumption, pollution, and structural vibration in aircrafts, submersibles, ships, and pipelines. Due to this integral effect, any progress in the control of TBLs will have a profound impact on our socio-economic and environmental protection needs. The subject of this research program is the control of attached and separated TBLs using a novel smart skin'. To achieve this goal, we will first experimentally characterize the surface pressure of large-scale motions in attached and separated TBLs to develop a predictive model for turbulence control. In parallel, we will develop deformable surfaces that can generate on-demand local surface depression or protrusion. Linear actuators, with a frequency and displacement that matches the pressure footprint, will be integrated under a deformable skin. We will implement an array of active deformable panels and surface pressure sensors into a smart skin'. Finally, the performance of the smart skin' will be evaluated in a closed-loop system for active control of attached and separated TBLs. In the long-term, the proposed program will increase our fundamental knowledge of coherent motions in TBLs and provide guidelines on how to control TBLs. The developed smart skin' will make it possible to manipulate a variety of turbulent flows including TBLs. The smart skin will also become a test-bench for the application of advanced control algorithms, artificial intelligence, and machine learning. Such an approach can ultimately modernize how we handle turbulence. It can make a breakthrough by bringing turbulence control to a variety of industrial sectors to increase efficiency and reduce environmental footprints. In addition, the multidisciplinary nature of this research program will train highly qualified personnel who are trained in a variety of disciplines.

边界层是固体表面附近的薄层流体层，其中流体速度从固体表面速度到块状流体速度的速度过渡。液体中的剪切应力会产生这种速度梯度，并在表面上以皮肤摩擦的形式投射。例如，在大多数工业情况下，飞机上或管道内部的流量，边界层中流体元素的运动是混乱的。这样的流体层被称为湍流边界层（TBL），并且具有更大的速度梯度，可以产生更大的皮肤摩擦。另外，当将增加的压力梯度施加在TBL上，例如在扩散器或飞机机翼上时，TBL可能与表面分开。这会产生压力阻力和强烈的流体结构相互作用。结果，TBL是飞机，潜水员，船只和管道中高油耗，污染和结构振动的主要来源。由于这种整体效果，控制TBL的任何进展都将对我们的社会经济和环境保护需求产生深远的影响。 该研究计划的主题是使用新颖的智能皮肤控制附着和分离的TBL。为了实现这一目标，我们将首先在实验中表征附着和分离的TBL中大规模运动的表面压力，以开发用于湍流控制的预测模型。同时，我们将开发可变形的表面，这些表面可以产生按需局部表面抑郁或突出。线性执行器具有与压力足迹相匹配的频率和位移，将集成在可变形的皮肤下。我们将在智能皮肤中实现一系列主动可变形面板和表面压力传感器。最后，将在闭环系统中评估智能皮肤的性能，以积极控制附着和分离的TBL。 从长远来看，该计划将增加我们对TBL中连贯动作的基本知识，并提供有关如何控制TBL的指南。发达的智能皮肤将使操纵包括TBL在内的各种湍流。智能皮肤还将成为应用高级控制算法，人工智能和机器学习的测试台。这种方法最终可以使我们如何处理湍流现代化。它可以通过将湍流控制带入各种工业部门来提高效率并降低环境足迹来取得突破。此外，该研究计划的多学科性质将培训接受各种学科的高素质培训的人员。