A Biomimetic Smart Control of Viscous Drag Reduction

Viscous flow drag represents the largest contingent of the entire drag that aerodynamic and hydrodynamic devices are subject to. Inspired by the functions of sharks skins, riblet surfaces have been studied and applied to wall structures to reduce turbulent flow drag. However, whilst structural similarity has been obtained it lacks true mimicry. This paper presents an approach of drag reduction using “Smart Surface”, a new propose composite surface that combines the riblet with an elastic coating. The “smart surface”, inspired by the self-adjustable skin of marine animals such as the dolphin, is designed to modify the traditional riblet technique and enable it to “sense” and interact with the flow by adjusting the wall structure according to the flow condition. Considering the factors of manufacture feasibility, durability and drag reduction performance in previous studies, the physical model of “Smart Surface” is designed. The preliminary establishment of corresponding prediction model has been discussed and calculated. Further work in the aspects of experimental and numerical study of this research is prospected. Key words: Drag reduction; Elastic coating; Riblet; Self-adjustable; Smart Surfac

Microflow valve control system design

A design synthesis for a microflow control system is presented based on the interrogation of an analytical model, testing, and observation. The key issues relating to controlling a microflow using a variable geometry flow channel are explored through the implementation and testing of open and closed-loop control systems. The reliance of closed-loop systems on accurate flow measurement and the need for an open-loop strategy are covered. A valve and control system capable of accurately controlling flowrates between 0.09 and 400 ml/h and with a range of 900:1 is demonstrated