High-definition PIV Analysis on Vortex Shedding in the Cylinder Wake

Article type: Research Article

Authors: Kim, W. | Sung, J. | Yoo, J.Y. | Lee, M.H.

Affiliations: School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea. E-mail: [email protected] | School of Mechanical and Automotive Engineering, Sunchon National University, Jeonnam 540-742, Korea | Department of Mechanical Engineering, Seoul National University of Technology, Seoul 139-743, Korea

Abstract: A high-definition analysis based on flow topology is made on the vortex motions under natural and lock-on conditions in the near-wake region of a circular cylinder, where two-dimensional flow fields in the wake-transition regime are measured by a time-resolved PIV system. The Reynolds stress distributions are examined in view of the mean separation streamline and the trajectory of the vortex center. It is shown that, by the lock-on, the Reynolds stresses become stronger and their dispositions match well with the shortened wake bubble, indicating perfect synchronization of shedding to the oscillatory forcing flow in the near field, which causes increased lift and drag forces.

Keywords: Time-Resolved PIV, Trajectory of Vortex Center, Wake Bubble, Lock-on

Journal: Journal of Visualization, vol. 7, no. 1, pp. 17-24, 2004