Research>Flow Control> Synthetic Jet Actuators

Background

Synthetic Jet Actuators (SJAs) are a class of flow control devices that can be used to inject fluid momentum into a flow. The devices work by using an oscillating diaphragm or piston to force air in and out of a chamber via a sharp edged orifice. A train of fluid slugs is ejected from the orifice and these eventually coalesce to form a free jet of fluid. The device is known as a 'synthetic' because there is no net mass flow through the orifice. SJAs for flow control applications are often based on oscillating diaphragms driven by piezo ceramics. SJAs are of interest for flow control applications because they lend themselves to micro manufacture and are potentially a convenient and efficient way of locally generating fluid momentum flow control inputs from an electrical power source.

Whilst SJAs have been shown to produce interesting results in the laboratory, there are a number of outstanding issues that need to be addressed before the technology can be usefully applied. The two main issues are: Are they effective? and: At what cost in terms of weight, power and volume is this level of effectiveness achieved?

SJA Research topics

• Understanding of the fundamental fluid mechanics of SJAs
• Understanding of the interaction of multiple SJAs in actuator 'arrays'
• SJA systems and certification
• SJA geometric optimisation for peak velocity and power efficiency

Publications

Crook, A., Crowther, W.J., Wood, N.J. ‘A parametric study of a synthetic jet in a cross flow’, 22nd International Congress of Aeronautical Sciences, Harrogate, UK, 2000

Garcillan, L., Liddle, S., Sunneechura, K., Crowther, W.J., Zhong, S. and Wood, N.J., ‘PIV measurements of the effect of pitch and skew on a circular orifice synthetic jet in a turbulent boundary layer’, AIAA-2006-0318

Gomes, L., Crowther, W.J., and Wood, N.J., ‘Towards a practical piezoceramic diaphragm based synthetic jet actuator for high subsonic applications – effect of chamber and orifice depth on actuator peak velocity’, AIAA-2006-2859.

Gomes, L., D., Crowther, W., Wood, N., J., “Towards a practical synthetic jet actuator for industrial scale flow control applications,” IUTAM Proceedings on Flow control and MEMS, Kluwer Academic Publishers, (2006)

11 June, 2007