For obtaining the verification data of the numerical analysis of an unsteady flow, the wall surface pressures of an elliptic cylinder were measured under different rotational speeds.The elliptic cylinder, which rotated around the center of the cylinder, was placed in a uniform flow so that the flow separation points moved periodically.The experiments were performed with the Reynolds number equal to or less than 1.26xl05, and a peripheral speed coefficient equal to or less than 0.0443.The pressure fluctuation due to Karman vortices remained even after the periodical averaging operation of the measured data at every rotation.Therefore, it could be elucidated that the discharging vortices were synchronized with the rotation angle of the elliptic cylinder. In addition, hysteresis phenomena, wherein the flow separation point near the leading edge differed according to the rotational direction, occurred even if the rotating speed was low.
