Computational Study of Wing-Tip Effect for Flow-Control Authority of Dielectric-Barrier-Discharge Plasma Actuator

In the present study, large-eddy simulations of a three-dimensional flow around the NACA 0015 wing controlled by a dielectric-barrier-discharge (DBD) plasma actuator (PA) were conducted, and the influence of the wing tip on the flow was investigated. A half-span rectangular wing with an aspect ratio (AR) of two was selected. The Reynolds number was set to 63,000, and the angles of attack were 12 and 14 deg as the poststall condition. In both cases, the overall L/D significantly increased by the DBD-PA. The increment of the L/D was small around the wing tip, owing to the wing-tip vortex; whereas it increased substantially in the area from the wing root to the midspan, as reported in the previous study (Sato, M., Aono, H., Yakeno, A., Nonomura, T., Fujii, K., Okada, K., and Asada, K., "Multifactorial Effects of Operating Conditions of Dielectric-Barrier-Discharge Plasma Actuator on Laminar-Separated-Flow Control," AIAA Journal, Vol. 53, No. 9, 2015, pp. 2544-2559) of a two-dimensional airfoil (that is, three-dimensional simulation with a two-dimensional airfoil without tip and root). This study also focused on the effect of the spanwise length of the DBD-PA and compared aerodynamic performance between four DBD-PA lengths to investigate an effective installation length in the current setting. Through the results, the factors that affect flow-control capability around a three-dimensional (3-D) wing (both those common in a two-dimensional airfoil and those peculiar in a 3-D wing) were discussed.