In this paper, three-dimensional turbulent flow models based on the computational fluid dynamics (CFD) method are established to investigate the effects of different rolling conditions (θₘₐₓ = 5°, 10°, and 15°; T = 1 s) on the flow around single circular cylinder at subcritical Reynolds number. The analysis focuses on the lift and drag coefficients, the position of the stagnation point, and the vortex shedding process at a Reynolds number of Re = 3900. Results indicate that the Strouhal number under rolling conditions is smaller than that under stationary (non-rolling) conditions. The dominant frequency of the lift coefficient deviates from the rolling frequency, whereas the dominant frequency of the drag coefficient shifts,from twice the natural vortex shedding frequency under stationary conditions,to a value close to the vortex shedding frequency under rolling motion; moreover, its vortex shedding characteristics loses sinusoidal symmetry. The front stagnation point migrates in response to the rolling motion, and its minimum angular position coincides with the instant when the additional vertical force acting on the cylinder reaches its maximum magnitude in the negative direction. Vortex shedding exhibits pronounced geometric asymmetry: vortices shed from upper cylinder surface are weaker and smaller in size compared to those from the lower surface, and the upper vortices shape becomes increasingly ellipsoidal rather circular. This study indicates that rolling conditions induced by the marine environment exert a unique influence on the flow around cylinder and vortex-induced vibration, during the development of relevant equipment, particular attention should be given to the unique effects of rolling conditions on flow-induced vibration.This paper provides a valuable reference for further fluid dynamic analysis and flow-induced vibration characterization of marine and offshore engineering structures.

Flow around cylinder,Numerical simulation,Vortex shedding,Rolling motion