City Research Online

Abstract

This thesis presents a set of three follow on experimental papers carried out on NACA 0012 aerofoils either with active trailing edge flaplets or an array of sensing hairs. The experiments investigate using pneumatics for active flow control via trailing edge flaplets and then bio-inspired sensing flow hairs, including a new camera setup for sensing hair monitoring.

The pneumatic flaplets were inspired by the pop-up feathers that birds have, that aid them during different flight manoeuvres. The flaplets were designed and tested before being used as an upstream gust generator. The sensing hairs were a continuation of work already carried out at City, University of London but were adapted to be an integrated sensing array. The tips of the hairs were monitored via PIV and their ability to detect flow structures was analysed. Finally, an EBC was considered as a replacement for the high-speed camera for
the same setup with the sensing hairs and showed potential for future studies.

The first study was a fluid dynamics study via PIV into the effect that the flaplets had on the nearby and downstream flow in the water tunnel. It was found that, during the opening stages of the flaplet, fluid is drawn in from the boundary layer and then expelled during the closing stages, generating a vortex that travels downstream.

The second study used an integrated array of flow-sensing hairs, placed downstream of the gust generator. The movement of the tips of the hairs was monitored via a high-speed camera and was compared to PIV images taken at the same location, under the same tunnel conditions. It was found that the hairs can detect the arrival, size and structure of the flow disturbance, giving us a flow ’footprint’.

The third study was a feasibility study, into using an EBC in place of a high-speed camera with the sensing hairs. Comparative experiments were carried out in both air and water using both cameras and the sensing hairs under different flow conditions. The results demonstrate the ability that the EBCs have to detect large flow structures and show promise for real-time flow monitoring.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > T Technology (General) T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics
Departments:	Doctoral Theses Interdisciplinary Centres

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