Investigation of vortical flow characteristics around a partially buried circular cylinder

• Published in: Ocean engineering 2012-10, Vol.52, p.35-51
• Main Author: Sami Akoz, M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buildings. Public works; Computation methods. Tables. Charts; Exact sciences and technology; Hydraulic constructions; Offshore structure (platforms, tanks, etc.); Partially buried cylinder; Particle image velocimetry; Reynolds stress; Separation; Steady flow; Structural analysis. Stresses; Turbulent kinetic energy; Velocity field
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2012.06.011

The interaction of vortical flow with a cylindrical structure is encountered in a variety of engineering applications. Determination of the affected flow structure in terms of its kinematics and related properties is important for the study of fluid-body interaction problems. In this study, the PIV technique is used to measure the velocity field of two-dimensional turbulent flow around a partially buried circular cylinder on a smooth plane boundary. Experiments are conducted in a closed-loop water channel for flow conditions with Reynolds numbers based on the cylinder diameter, ReD=1000, 3000, 5000 and 7000. Instantaneous and time-averaged patterns of velocity vectors, corresponding streamline topology, vorticity contours and distributions of turbulence statistical quantities are presented for the burial ratios, B/D=0.25 and B/D=0.50 to provide a detailed evaluation of the vortical flow characteristics. Moreover, the effect of burial ratio on the wall boundary-layer separation upstream and downstream of the circular cylinder and, the positions of the separation points on the cylinder surface are investigated. ► The velocity field around a partially buried cylinder was measured using the PIV system. ► The experiments were repeated with the burial ratios of B/D=0.25 and 0.50 for 1000≤ReD ≤7000. ► The vortical flow characteristics around the partially buried cylinder change with time. ► The lengths of the separation region upstream and downstream of the cylinder depend on B/D and ReD. ► The distributions of the turbulent intensity, kinetic energy and Reynolds stress depend on B/D and ReD.