内部循環流を誘発するキャビティ翼の空力特性

抄録

There is one of the advanced flow control technique called “Trapped vortex cell (TVC)” control. This technique requires a properly shaped cavity positioned along the spanwise direction on the upper surface of the airfoil. In this study, the final goal is to reveal how the cavity shape is related to the performance of the Cavity wing (referred to as CW). We focused on the two types CW: Closed CW and Opened CW. Between these two CWs, there is a difference in the shape of the trailing edge. We did flow visualization around the Opened CW. We confirmed recirculation flow in the cavity, but it was unsteady. Flow pattern in the cavity was almost same when increasing the angle of attack. We expected that CW has some lift force from 0 to deg based on this flow pattern. We obtained lift curves of these wings by wind tunnel testing. It shows that CWs can get higher lift coefficient than NACA0020 (referred to as NACA) that is the original shape of CWs when the angle of attack is 5 deg. And it was also revealed that there are almost no differences between NACA and CWs lift coefficients when the cavity is the lower surface of the airfoil. But these trends don’t agree with the result of the visualization. We suppose that a difference of Reynolds numbers between the investigation of lift curves and the visualization induced this mismatch. We performed the visualization with a lower Reynolds number because of limits of performance of visualization facilities.