Streamwise and spanwise plasma actuators for flow-induced cavity noise control

Abstract

Plasma actuators operating in atmospheric air can induce a body force through collisions between electrically charged particles and neutral air molecules by an externally applied electric field. The fast response and the simple structure make the plasma actuator a promising option in aerospace applications. In this work, experiments were performed with several alternative current excited plasma ͑streamwise and spanwise͒ actuators to control flow-induced noise from a cavity. It was found that the streamwise actuator induced three-dimensional variations in the shear layer. The spanwise actuator, however, has little influence on the global flow field. As a result, the streamwise actuator is more effective than the spanwise actuator in cavity noise attenuation.

On the formation of streamwise vortices by plasma vortex generators

“…Roth, Sherman & Wilkinson (2000) demonstrated that these actuators can cause significant changes in friction drag on a flat plate boundary layer. This has spurred a plethora of studies, particularly in low-Reynolds-number air flows, with the aim of drag reduction (Wilkinson 2003;Jukes et al 2006b;Choi, Jukes & Whalley 2011), lift enhancement (Little et al 2010;Feng et al 2012;Greenblatt, Schneider & Schule 2012), flow separation control (Post & Corke 2006;He, Corke & Patel 2009;Schatzman & Thomas 2010), vortex shedding control (Thomas, Kozlov & Corke 2008;Jukes & Choi 2009a,b,c), transition control (Grundmann & Tropea 2008;Hanson et al 2010) and noise control (Huang & Zhang 2008). Further information on operating principles and flow control applications can be found in the review articles by Moreau (2007), Corke, Post & Orlov (2009) and Wang et al (2013).…”

“…Chan, Zhang & Gabriel (2007) and Huang & Zhang (2008) used DBD-VGs for noise control upstream of a rectangular cavity. The streamwise vortices impeded development of organized structures within the cavity, which disrupted the fluidacoustic feedback mechanism to reduce the aerodynamic noise.…”

Role of longitudinal vortices induced by jets in upstream boundary layer on suppression of cavity tone

“…It was shown that longitudinal vortices were induced by the jets and cavity tone was suppressed effectively. As shown in the previous research [1][2][3][4], it is revealed that upstream flow control was effective to reduce the cavity tone. However, reduction mechanism of cavity tone and effects of spacing of jets on cavity flow has not been clarified.…”

“…There have been many attempts to reduce the cavity tone by various methods such as plasma actuators, synthetic jets and blowing jets [1,2]. Huang et al [3] attempted to control cavity tone by plasma actuators in the upstream boundary layer and investigated the effects of the direction of the plasma actuators on suppression of the cavity tone. It was shown that streamwise plasma actuators, which spanwisely induced flow, were more effective in the noise reduction than a spanmwise plasma actuator.…”

Turbulent boundary-layer control with plasma spanwise travelling waves

“…DBD plasma actuators have been used for separation control of aerofoils (Corke et al 2010(Corke et al , 2011Whalley et al 2013), vortex shedding control of bluff bodies (Munska and McLaughlin 2003;McLaughlin et al 2004;Jukes and Choi 2009), delaying laminar-to-turbulent transition (Grundmann and Tropea 2007) and noise reduction of cavity flows (Huang and Zhang 2008). Wilkinson (2003) created a spanwise flow oscillation in the turbulent boundary layer with DBD plasma actuators by applying a frequency modulating input to a pair of lower electrodes on either side of an upper electrode.…”