247 3次元円盤翼に働く非定常流体力(S41-2 移動境界・連成(2),S41 移動境界・連成・振動と騒音問題)  [in Japanese] 247 Unsteady Forces on a 3-Dimensional Disc Type Airfoil  [in Japanese]

The unsteady forces act on the pitching and heaving airfoil. In this study, we measured unsteady forces on a moving 3-dimensional disc type airfoil using load cell and related to the vortices in the wake using PTV. We examined the relation among fluid forces, angle of attack, reduced frequency and vorticity. As a result, it was found that pitehing motion makes the angle of stall larger and lift coefficient depends on reduced frequency. These are same characteristics of 2-dimensional airfoil. We observed the shedding of vortices at the transition instant of pitching motion from up-stroke to down-stroke.