Hydrodynamic characteristics of hyperbolic cylinder under periodic pulsating flow at moderately high Reynolds number (Re=3900)

Abstract

In this paper, the hydrodynamic characteristics of a hyperbolic cylinder under periodic pulsating flow are studied. The non-uniform turbulent flow is formed by a periodically oscillating wing structure placed upstream of the hyperbolic cylinder. The influence of different oscillation velocities and oscillation amplitudes of the upstream wing structure and the horizontal distance between the wing structure and the hyperbolic cylinder on the hydrodynamic characteristics of the downstream hyperbolic cylinder is studied, and the results indicate that the hydrodynamic characteristics of the hyperbolic cylinder are mainly determined by leading-edge vortices and trailing-edge vortices of the upstream wing structure and the vortex shedding of cylinder itself. Further, the distance between the wing and cylinder has an obvious influence on the hydrodynamic characteristics of the cylinder owing to the difference in the diffusion range of the vortex. Also, the different oscillation velocities of the upstream wing lead to a difference in the attachment vortices on the hyperbolic cylinder, which indicates the positive or negative drag coefficient. Moreover, a critical value of the oscillation amplitude exists for each oscillation velocity value, so the hyperbolic cylinder is subjected to a minimum force under the periodic pulsating incoming flow.