ピッチング運動翼から発生する渦の挙動と非定常流体力

抄録

In the present study flow patterns around pitching airfoils such as a NACA 65-0910 and BTE have been visualized by three kinds of dyes in a water tunnel at low Reynolds number region, Re=4.0×10³.Moreover, the dynamic lift and drag acting on them have been measured by a six-axes sensor.At the angle of attack α=16±6 deg., where the separation occurs under the stationary condition, and at higher non-dimensional pitching rate, the vortex with clockwise rotation shed from the leading edge reattaches on the suction surface and the re-circulation region was formed on the suction surface. It interferes with the other vortex with counter clockwise rotation shed from the trailing edge. They form a cloud of vortices behind five chords length distant from the trailing edge.The dynamic lift is much higher than the stationary one because of the re-circulation region on the suction surface. The dynamic behavior of vortices on the suction surface influences the dynamic lift strongly.