Flow control with EHD actuators in middle post stall regime

Abstract

We analyze the modifications of the flow around a NACA 0015 airfoil when the flow is perturbed with an electrohydrodynamic (EHD) actuator. The device used consists of two bare electrodes flush mounted on the surface of the model operated in a discharge regime characterized by the formation of a plasma sheet contouring the body in the interelectrode space. In this study, we analyze the influence on the aerodynamic performance of the airfoil in the middle post stall regime (angle of attack<FONT FACE=Symbol>&raquo;</FONT>20º). The analysis is undertaken with measurements of the surface pressure distribution and of the flow fields with Particle Image Velocimetry technique. The experiments indicate that at moderate Reynolds numbers (150,000<Re<333,000), the actuator enables a reattachment of the flow and reveals an important sensitivity of the middle post stall regime to periodic excitation

Aerodynamic Flow Control

“…Recent decades have witnessed significant advances in zero and nonzero mass-flux devices including piezoelectric (Chen et al, 2000;Glezer and Amitay, 2002) valve-type (Seifert, Darabi and Wygnanski, 1996;Bachar, 2001;Seifert and Pack, 1999) and pulsed combustion or detonation-driven (Crittenden et al, 2001) devices. The same is true for surface-mounted actuators that include piezoelectric , plasma-based (Sosa et al, 2006;Post and Corke, 2004), arc filament (Samimy et al, 2004), shape memory alloys (Wlezien et al, 1998), and Lorentz force (Weier and Gerbeth, 2004) actuators. Perturbations produced by the actuators may be small relative to a characteristic velocity or vehicle dimension and thus exploit boundary layer instability; but they may also be much larger and hence "force" the flow, for example, by high-frequency alternating blowing and suction.…”