Deflection-based flow field sensors - Examples and requirements

Abstract

The assessment of near-wall fluid motion, acoustic vibrations, or wall-shear stress is essential in many biological and engineering systems. This necessity is evidenced by a huge diversity of sensing devices in both fields. While nature shows a broad diversity of filiform hair-like fluid sensing devices1 which have been improved towards perfection over millions of years, researchers have recently attempted to copy and adapt these biological examples for technical applications. In particular the fish lateral line flow sensor and the filiform arthropod hairlike medium motion sensors have inspired researchers to develop artificial hair sensor arrays based on flexible cantilevers and micro-posts. Therefore, in this article, after a brief description of some examples of biological deflection-based sensor devices, recent man-made cantilever-based sensors for the detection of near-wall fluid motion and wall-shear stress will be discussed. Furthermore, the advantages and disadvantages of different designs and general fluid-mechanical and technical requirements for flow sensors will be outlined.