Grant: Discovery Grants Program - Individual

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.