Development of smart surfaces for flow management/re-arrangement

许多工业产品都含有流动系统，其性能会影响产品的整体性能，特别是与其运行相关的能源成本。能源成本的降低主要可以通过减少阻力来实现。目前的工作重点是开发智能表面，这将为有效管理/重新安排流动提供一种手段。寻找能够减少表面摩擦层流阻力、通过延迟/加速层流-湍流转变来影响阻力、通过重新布置主体流动来减少湍流阻力以及产生湍流的表面。 对固体界面流体力学的理解为智能曲面的开发奠定了基础。例如，表面形貌、微电子机械装置、合成射流、脉冲吹气、等离子体激励器、壁面蒸腾和加热都会影响流动动力学。所有这些效应都为流动强迫(控制驱动)的产生提供了手段。理解使用不同形式的强迫可以在流程中创造的变化形成了这项工作的核心。 流动性质的显著变化通常需要使用强强迫。在这项工作中，使用了大量简单、弱的致动器(成群的致动器)。这种致动器只需要很小的能量输入，但只有在它们形成图案时才能有效。正是这些模式(而不是单个执行器)的相互作用可能会产生所需的流动响应。这项工作的目的是研究哪些流型具有重要的水力意义，以及可以实现哪些类型的流动响应。这项工作的重点是基于简单致动器的模式创建智能表面，这一工作有别于任何其他竞争的方法。 智能表面具有广泛的应用，例如在航空航天、造船、制药和生物医疗等行业。

Many industrial products contain flow systems whose performance affects the overall product capabilities, especially the energy cost associated with their operation. Reduction of the energy cost may come primarily through the reduction of drag. The present work is focused on the development of smart surfaces that would provide a means for an effective management/re-arranging of flows. Surfaces that reduce the skin friction laminar drag, affect the drag by delaying/accelerating the laminar-turbulent transition and reduce the turbulent drag by re-arranging the bulk flow, as well as turbulence production, are sought. An understanding of the fluid mechanics at the solid interfaces provides a basis for the development of smart surfaces. The flow dynamics can be influenced by surface topography, micro-electro-mechanical devices, synthetic jets, pulsed-blowing, plasma actuators, wall transpiration and heating, for example. All these effects provide means for the creation of flow forcing (control actuation). An understanding of the changes that can be created in the flow using different forms of forcing forms the core of this work. A significant change of flow properties typically requires the use of strong forcing. The use of a large number of simple, weak actuators (a swarming of actuators) is pursued in this work. Such actuators require only a small energy input but can be effective only if they form patterns. It is the interaction of such patterns (rather than the individual actuators) that may produce the desired flow response. The objective of this work is to study what patterns are hydraulically significant and what kinds of flow response can be achieved. The focus on the creation of smart surfaces, based on patterns of simple actuators, differentiates this work from any other competing approaches. Smart surfaces have a wide range of applications, for example in the aerospace, ship-building, pharmaceutical and bio-medical industries, among others.