電磁型ミニアクチュエータを用いた対称翼の失速制御(流体工学,流体機械)  [in Japanese] Stall Control of a Symmetric Airfoil by Means of Miniature Electromagnetic Actuators(Fluids Engineering)  [in Japanese]

Lift and drag characteristics of a symmetric NACA 0012 airfoil in a low Reynolds number range have been investigated when miniature electromagnetic actuators attached on the airfoil have been operated in order to control the flow separation and the stall. Flow visualizations including PIV method have also been made to examine the flow separation structure of the airfoil. At a small attack angle just after the stall, the periodical actuation generates the vortex in phase. This induced vortex flows near the surface of the airfoil and noticeably decreases the dead water area so that the maximum lift coefficient increases by 25% and the angle of stall increases by 3 degree with the actuation. At a relative large attack angle, among the several types of the actuation patterns tried, only the in phase actuations with selective frequency can suppress the abrupt drop of the lift force owing to the generations of a large-scale vortex and its strong downward flow toward the airfoil near the trailing edge, although this large-scale vortex no longer contributes to reduce the dead water area.